http://tih.sagepub.com/Toxicology and Industrial Health
http://tih.sagepub.com/content/early/2013/06/21/0748233713485887The online version of this article can be found at:
DOI: 10.1177/0748233713485887
published online 24 June 2013Toxicol Ind HealthTarek Mostafa Mohammed, Afrah F. Salama, Tarek M. El Nimr and Doaa M. El Gamal
Effects of phytate on thyroid gland of rats intoxicated with cadmium
Published by:
http://www.sagepublications.com
can be found at:Toxicology and Industrial HealthAdditional services and information for
http://tih.sagepub.com/cgi/alertsEmail Alerts:
http://tih.sagepub.com/subscriptionsSubscriptions:
http://www.sagepub.com/journalsReprints.navReprints:
http://www.sagepub.com/journalsPermissions.navPermissions:
What is This?
- Jun 24, 2013OnlineFirst Version of Record >>
at DONGGUK UNIV LIB on November 10, 2014tih.sagepub.comDownloaded from at DONGGUK UNIV LIB on November 10, 2014tih.sagepub.comDownloaded from
Article
Effects of phytate on thyroid gland ofrats intoxicated with cadmium
Tarek Mostafa Mohamed1, Afrah F Salama1,Tarek M El Nimr2 and Doaa M El Gamal1
AbstractCadmium (Cd) is one of the most dangerous occupational and environmental toxins. The objective of the presentstudy is to examine the potential prophylactic effects of phytic acid (PA) on thyroid hormones of male ratsintoxicated with Cd. The male albino rats were divided into five groups: group I (control) was fed with the basaldiet, group II was intoxicated with Cd in drinking water, groups III, IV, and V were intoxicated with Cd in drinkingwater and fed with the diet containing 3.5, 7, and 10 g of PA/kg, respectively. The results indicated that the serumcalcium, iron (Fe), and total Fe binding capacity levels and serum T3 and T4 in Cd-treated rats of group II weredecreased when compared with the control group, while PA-administered groups with Cd showed a significantimprovement when compared with the Cd-treated rats only. Serum thyroid stimulating hormone (TSH) level wassignificantly increased in Cd-treated rats compared with the control group, while the addition of PA in dietdecreased the high levels of TSH. These results indicated a prophylactic effect of PA against Cd-induced toxicityin rats.
KeywordsCadmium, phytic acid, thyroid, T3, T4, TSH, toxicity
Introduction
Cadmium (Cd) is a well-known environmental pollu-
tant. Cd usage has increased dramatically during the
last 40–50 years because of the metal’s high resistance
to corrosion and valuable electrochemical properties.
Humans are exposed to Cd through tobacco smoke,
food, industrial, occupational, and environmental pol-
lution (Mitra et al., 2012). Since biological half life
of Cd in humans is found to be more than 20 years and
Cd has the ability to induce severe alterations in vari-
ous organs and tissues following either acute or chronic
exposure, it has been recognized as one of the most
toxic environmental heavy metal pollutants (Mitra
et al., 2012 and Urani et al., 2007).
Cd toxicity causes renal damage, coronary artery dis-
ease, hypertension, emphysema, and other chronic pul-
monary diseases (Ahn et al., 1999; Hu, 2000 and
Shagirtha and Pari, 2011). Cd interacts with the metabo-
lism of four metals: zinc (Zn), iron (Fe), calcium (Ca),
and copper (Bremner and Campbell, 1978; Hayter,
1980 and Petering, 1978). Also, Cd toxicity leads to an
increase in brain deiodinase activity, and decrease in
serum T4 levels, and it also leads to impaired brain
development (Bianco et al., 2002).
The function of the thyroid hormones is stimulation
of heart contractions, maintenance of body weight,
stimulation of protein synthesis and carbohydrate
metabolism, and increase the synthesis and degrada-
tion of cholesterol and triglycerides, that is, regulation
of basal metabolic rate (Czajk-Narins, 1986).
Phytic acid (inositol hexaphosphate; IP6) or phytate
(PA; when its salt is formed) is the principal storage
form of phosphorus in many plant tissues, especially
bran and seeds (Minihan and Rimbach, 2002). It is found
1 Biochemistry Division, Chemistry Department, Faculty ofScience, Tanta University, Tanta, Egypt2 Biophysics Division, Physics Department, Faculty of Science,Tanta University, Tanta, Egypt
Corresponding author:Tarek Mostafa Mohamed, Biochemistry Division, ChemistryDepartment, Faculty of Science, Tanta University, El-Bahr Street,Tanta, El-Gharbia Governorate 31527, Egypt.Email: [email protected]
Toxicology and Industrial Health1–11© The Author(s) 2013Reprints and permissions:sagepub.co.uk/journalsPermissions.navDOI: 10.1177/0748233713485887tih.sagepub.com
at DONGGUK UNIV LIB on November 10, 2014tih.sagepub.comDownloaded from
in large amounts in unrefined cereals and legumes that
are consumed as staple foods in many countries (Gibson
et al., 2010). IP6 is regarded as an antinutritive factor.
The antinutritional effect of IP6 is primarily related to
the strong chelation associated with its six reactive phos-
phate groups (Urbano et al., 2000).
Potential beneficial effects of IP6 are to prevent over
mineralization of joints, blood vessels, and other parts
of the body. It prevents colon cancer by reducing oxi-
dative stress in the lumen of the intestinal tract, while
its negative effect contributes to mineral deficiencies,
especially in people with low intake of essential miner-
als. IP6 and Fe form insoluble complexes, which are
not available for absorption under the pH conditions
of the small intestine. In vitro studies indicated that
IP6 acts as an antioxidant through its Fe-chelating prop-
erties (Gibson et al., 2010; Minihan and Rimbach,
2002).
High IP6 diets cause Zn deficiency (i.e. the PA con-
tent is negatively correlated to Zn absorption), while
IP6 does not inhibit copper absorption. It has a modest
inhibitory effect on manganese absorption (Brown
et al., 2009; Lonnerdal, 2002). IP6 decreases magnesium
absorption and Ca absorption (Rimbach and Pallauf,
1997). Cd accumulation was estimated in liver and kid-
ney and was increased by the addition of Ca. PA inhib-
ited the increase in tissue Cd promoted by supplements
but did not influence tissue Cd values (Rose and Quar-
terman, 1984). In case of high dietary Zn, IP6 has few
effects on tissue concentration of Cd (Brown et al.,
2010; Rimbach and Pallauf, 1997).
The aim of the present study was to investigate the
hazardous effects of Cd as a heavy metal and the pro-
phylactic effect of IP6 on the structure and function of
male rats’ thyroid gland intoxicated with Cd.
Materials and methods
Experimental animals
A total of 50 adult male Sprague Dawley rats, aged
about 3 months and weighing (180–220 g), purchased
from the breeding unit of Egyptian Organization for
Biological Products and Vaccines (Abbassia, Cairo,
Egypt) were used throughout the present work. The
animals were housed in steel mesh cages and main-
tained for 1 week acclimatization period on commercial
standard diet and drinking water ad libitum as shown in
Table 1 (NRC, 1995). The housing cycle was 12 h
light and 12 hdark cycle under controlled temperature
(20–22�C). The animals’ body weight was noted every
week throughout the entire period of experiment (Briet
et al., 2003; Madapallimattam et al., 2002).All the rats
were randomly divided into five groups with 10 rats in
each group. The groups were group I (control group),
animals were fed with normal diet free of sodium PA
and were allowed to Cd-free drinking water for 4 weeks;
group II, animals were intoxicated with 50 mg Cd/L as
cadmium chloride (81.69 mg) added to the drinking
water daily for 4 weeks; groups III, IV, and V, animals
were intoxicated with Cd as in group II and fed with the
diet containing 3.5, 7, and 10 g sodium PA/kg for 4
weeks, respectively.
Methods
At the end of the experiment (4 weeks), the rats were
killed under anesthesia with diethyl ether as approved
by the Ethical Committee of Tanta University. Blood
samples were collected from orbital venous plexus
and divided into two parts. The first part was collected
into a heparinized tube and mixed well to prevent any
clot formation, and the blood specimens were refri-
gerated (at 4�C) until assayed for blood Cd levels.
The second part was centrifuged at 3000 r/min for
10 min at room temperature; serum was separated and
kept at �20�C until assay. Serum was used for the
determination of biochemical parameters.
Determination of Cd concentration
Whole blood and liver and kidney tissues were
assayed according to the method of Razniewska and
Trzcinka-Ochocka (1995).
Determination of serum Ca, Fe, and Fe bindingcapacity concentrations
Serum Ca and Fe concentrations were assayed using
the commercial kits supplied by Human Co. (Wiesbaden,
Germany) (Callahan and Cook, 1982; Pollard and Marun,
1956). Total Fe binding capacity in serum was assayed
using the commercial kit supplied by ELI Tech Co. (ELI
Tech. Co., France) (Anderson and Cockayne, 1993).
Determination of serum T3, T4, and TSHhormone concentration
Serum triiodothyronine (T3) hormone concentration
and thyroxine (T4) hormone level in serum were assayed
using the commercial kit supplied by Coat-A-Count
(Los Angeles, California, USA) (Hollander et al.,
1972; Prince and Ramsden, 1977). Thyroid stimulating
hormone (TSH) concentration in serum was assayed
2 Toxicology and Industrial Health
at DONGGUK UNIV LIB on November 10, 2014tih.sagepub.comDownloaded from
using the commercial kit supplied by Coat-A-Count
TSH IRMA from the Institute of Isotopes Ltd, Budapest
(Beijing Atom High-Tech Co. Ltd, China).
Histopathological investigation
The thyroid gland from the rats was taken and fixed in
10% buffered formalin, embedded in pure paraffin
wax (melting point of 58�C), and then mounted into
blocks and left at 4�C until the time of use. The par-
affin blocks were sectioned using the microtome at
a thickness of 5 mm and mounted on clean glass slides
and then left in the oven at 40�C for drying. The slides
were deparaffinized in xylol and then immersed in the
descending series of alcohol (90%–50%). The ordi-
nary hematoxylin and eosin stain were used for stain-
ing (Drury and Wallington, 1980).
Statistical analysis
Data are presented as mean + SD. One-way analysis
of variance followed by Tukey’s multiple comparison
method was carried out to compare the mean value of
different groups using SPSS 7.5 student version 3.
Comparisons were made between groups I and II–V
and between groups II and III–V. A p < 0.05 was con-
sidered statistically significant.
Table 1. The body weight of male rats in different groups at the start and at the end of work and the percentage of bodyweight changes.
Parametersgroups
Body weight (g)Percentage of body
weight changesaAt start At the end
Group In 10 10 15.15% "Range 180–220 200–260Mean + SD 198 + 14.30 228 + 21.19
Group IICd intoxicated
n 10 10 �17.8% #Range 170–230 150–200Mean + SD 196 + 19.55 161 + 17.29p Value 0.0001
Group IIICd intoxicated þ 3.5 g sodium PA
n 10 10 4.5% "Range 190–247 200–260Mean + SD 214.70 + 23.78 230 + 19.44p Value NSp* Value <0.0001
Group IVCd intoxicated þ 7 g sodium PA
n 10 10 15.9% "Range 180–220 200–250Mean + SD 194 + 12.65 225 + 15.09p Value NSp* Value <0.0001
Group VCd intoxicated þ 10 g sodium PA
n 10 10 5.9% "Range 180–230 220–250Mean + SD 201 + 15.95 235 + 10p Value NSp* Value <0.0001
Cd: cadmium; PA: phytate; NS: not significant.aChange in weight between the start and end of experiment. The significance of difference was analyzed using one-way analysis of var-iance. p value: value versus control (Group I). p* value: value versus Cd group (II).
Mohamed et al. 3
at DONGGUK UNIV LIB on November 10, 2014tih.sagepub.comDownloaded from
Results
The body weight of rats intoxicated with Cd only
(group II) showed a significant decrease as compared
to the normal rats (group I). On the other hand, there
were insignificant changes in the body weights of rats
in groups III, IV, and V as compared to the control
group; however, the body weight in rats intoxicated
with Cd and fed with different concentrations of
sodium PA was significantly elevated as compared
to Cd-intoxicated rats (group II; Table 1).
The blood Cd level of control male rats fed with
basal diet free of sodium PA (group I) was lower than
the detected limit, while the blood Cd level in rats
administrated with only Cd was 8.8 mg/L. The blood
Cd level in rats administrated with Cd and fed with the
diet containing 3.5, 7, and 10 g sodium PA/kg was sig-
nificantly decreased when compared with the Cd-
intoxicated rats. The Cd concentration in kidney was
higher than that in liver in all the five groups. There
were insignificant changes in the concentration of Cd
in the liver of rats administrated with Cd and fed with
the diet containing 3.5, 7, and 10 g sodium PA/kg com-
pared with the rats administrated with only Cd. How-
ever, the Cd concentration in kidney was not changed
from that of the rats administrated with Cd and fed with
the different concentrations of PA (Table 2).
Serum Ca levels in Cd-intoxicated rats were signif-
icantly decreased when compared with the control
rats, while serum Ca levels in rats administrated with
Cd and fed with the diet containing 3.5, 7, and 10 g
sodium PA/kg showed a significant increase when
compared with the Cd group (Table 2).
There was a significant decrease in serum Fe and total
Fe binding capacity levels in rats intoxicated with Cd
compared with the control group. In rats administrated
with Cd and fed with different concentrations of PA, the
serum Fe and total Fe binding capacity levels were
slightly increased but still insignificantly decreased
when compared with the control group (Table 3).
Serum T3 and T4 levels were reduced significantly
in male rats intoxicated with Cd compared with the
Table 2. Blood Cd concentration (in microgram per liter), Cd distribution in liver and kidney tissues (in microgramper gram) and serum Ca concentration (in milligram per deciliter) in the different groups.a
Parameters Groups Serum Cd (mg/L)
Cd Tissues
Serum Ca(mg/dL)Liver (mg/g)
Kidney(mg/g)
Group I (Control)Range – 0.09–0.2 0.2–0.3 10.48 – 12.27Means + SD 0.15 + 0.06 0.29 + 0.08 11.5 + 0.53
Group II (Cd intoxicated)Range 5-12 0.2-0.35 0.35-0.45 8.9–10.6Mean + SD 8.8 + 2 0.25 + 0.07 0.39 + 0.05 9.6 + 0.59p value – <0.01 <0.01 <0.001
Group III (Cd intoxicated þ 3.5 g sodium PA)Range 4.9–6.6 0.08–0.3 0.28–0.46 8.84–11.1Mean + SD 5.6 + 0.6 0.29 + 0.15 0.42 + 0.09 10.15 + 0.6p value – <0.05 <0.01 <0. 001p* value <0.05 NS NS <0.05
Group IV (Cd intoxicated þ 7 g sodium PA)Range 2.5–5.2 0.06–0.26 0.22–0.46 9.2–11.8Mean + SD 3.9 + 1 0.22 + 0.1 0.41 + 0.12 10.34 + 0.7p value – N.S. < 0.05 < 0. 001p* value <0.001 NS NS <0.02
Group V (Cd intoxicated þ 10 g sodium PA)Range 3.7–6 0.03–0.3 0.21–0.5 8.8–10.8Mean + SD 5.1 + 0. 7 0.24 + 0.16 0.39 + 0.15 9.5 + 7p value – NS <0.01 <0. 001p* value <0.001 NS NS NS
Cd: cadmium; PA: phytate; NS: not significant.aThe significance of difference was analyzed using one-way analysis of variance. p value: value versus control (group I). p*value: valueversus Cd group (II).
4 Toxicology and Industrial Health
at DONGGUK UNIV LIB on November 10, 2014tih.sagepub.comDownloaded from
control group, whereas the serum TSH level showed a
significant increase compared with the control rats. In
rats administrated with Cd and fed with the diet con-
taining 3.5, 7, and 10 g sodium PA/kg, the serum T3
and T4 levels were elevated nearer to the levels in the
control group and serum TSH level was reduced com-
pared to rats administrated with only Cd (Table 4).
In Cd-intoxicated rats and rats intoxicated with Cd
and fed with the diet containing 3.5, 7, and 10 g sodium
PA/kg, a significant negative correlation was detected
between serum T3 and blood Cd level. Also, serum
T4 had a significant negative correlation with blood
Cd level. In rats administrated with Cd and rats intoxi-
cated with Cd and fed with the diet containing 3.5, 7,
and 10 g sodium PA/kg, a significant positive correla-
tion was observed between serum TSH and blood Cd
level; also, the ratio of T3 and T4 had a significant pos-
itive correlation with blood Cd level (Table 5). In rats
intoxicated with Cd and rats intoxicated with Cd and
fed with the diet containing 3.5, 7, and 10 g sodium
PA/kg, insignificant correlation was observed between
T3/T4 ratio and serum T3 level. On the other hand, there
was a significant negative correlation between T3/T4
ratio and serum T4 level. However, there was an insig-
nificant correlation between T3/T4 ratio and TSH level
(Table 5).
Histological results in rats administrated with Cd
showed damage in the structure of the follicular cells
of thyroid gland and sheets of mature lymphocytes
with acute inflammatory cellular infiltration in the
form of neutrophils (Figure 1(b)). Thyroid gland of
rats intoxicated with Cd and fed with the diet contain-
ing 3.5, 7, and 10 g sodium PA/kg (Figure 2(a) to (c),
respectively) showed dilated oval thyroid follicles
filled with colloid and lined by a single layer of flat
to cuboidal cells having bland small nuclei as an indi-
cation of the prophylactic effect of IP6 on the thyroid
gland of rats intoxicated with Cd.
Discussion
The accumulation and toxicity of Cd in human and
animals depend on various factors such as the daily
intake, the form of Cd in food and food stuffs, and its
multiple interactions with the dietary components
(Mitra et al., 2012 and Rambeck, 1994).
Table 3. Serum Fe concentration (in microgram per deciliter), total Fe-binding capacity (in microgram per deciliter) andblood hemoglobin concentration (in gram per deciliter) in different groups.a
Parameters Groups Fe (mg/dL)Total Fe-bindingcapacity (mg/dL) Hemoglobin (g/dL)
Group I (Control)Range 135.3–183.9 311–613 12.9–16.8Means + SD 152.7 + 16.6 487.3 + 90 14.7 + 1.1
Group II (Cd intoxicated)Range 97–140 264–474 7.5–9.9Mean + SD 114.3 + 14. 404.9 + 76.5 8.06 + 0.6p Value <0.001 <0.05 <0.001
Group III (Cd in toxicated þ 3.5 g sodium PA)Range 102–183 235.8–613.2 7.9–12.3Mean + SD 122.2 + 24.4 413.4 + 117 10.08 + 1.3p Value <0.01 NS <0.001p* Value NS NS <0.001
Group IV (Cd intoxicated þ 7 g sodium PA)Range 120–183 349–577.3 9.7–14.8Mean + SD 130 + 24.4 443.1 + 80 12.1 + 1.6p Value 0.004 NS <0.001p* Value NS NS < 0.001
Group V (Cd intoxicated þ 10 g sodium PA)Range 83–135 301.9–560.4 9–14.4Mean + SD 106.1 + 17.4 439.7 + 98 11.69 + 1.7p Value <0.001 NS <0.001p* Value NS NS <0.001
Cd: cadmium; PA: phytate; NS: not significant; Fe: iron.aThe significance of difference was analyzed using one-way analysis of variance. p: value versus control rats (group I). p*: value versus ratsfed with Cd (group II).
Mohamed et al. 5
at DONGGUK UNIV LIB on November 10, 2014tih.sagepub.comDownloaded from
IP6 is a natural plant compound with a unique struc-
ture that is responsible for its characteristic properties
(Gibson et al., 2010 and Tsao et al., 1997). In the pres-
ent study, it was shown that the body weight of male
rats fed with normal diet free of sodium PA increased
by 15.15% at the end of the experiment. Chronic
administration of Cd led to marked decrease in the
body weight of rats fed with diet free of sodium PA.
The decrease in body weight gain of rats exposed
to Cd could be the result of lowered food and water
intakes, since addition of Cd into drinking water
resulted in a significant decrease in its consumption
especially Cd has a bad taste (Brus et al., 1999; Gupta
and Gill, 2000 and Strbak et al., 1998). The lowered
body weight in the Cd-treated rats may indicate malnu-
trition due to Cd toxicity (Katsumi et al., 1984). On the
other hand, this study showed that the body weight of
rats administrated with Cd and fed with the diet con-
taining 3.5, 7, and 10 g sodium PA/kg was increased
The sodium PA may decrease the Cd absorption in rats
hence decreases the Cd effect on the body weight.
The different concentrations of sodium PA in Cd-
intoxicated groups reflected by the concentration of
Cd in the blood, liver, and kidney. The concentration
Table 4. Serum T3; (in nanogram per deciliter), T4(in microgram per deciliter), and TSH (in micro international units permilliliter) in different male rat groups.a
Parameters Groups T3 (ng/ dL) T4 (mg/ dL) T3/T4 ratio X 10�3 TSH (mIU/mL)
Group I (Control)Range 112–128 5.5–8.6 1.3620.36 0.06–0.11Means + SD 120.1 + 5.4 7.08 + 1.03 17.146 + 2.40 0.08 + 0.01
Group II (Cd intoxicated)Range 67.2–108 2.6–5.2 17.73–37.4 0.11–0.29Mean + SD 88.6 + 11.9 3.8 + 0.9 23.862 + 6.12 0.17 + 0.06p Value <0.001 <0. 001 <0.01 <0.001
Group III (Cd intoxicated þ 3.5 g sodium PA)Range 83–120 3.9–5.7 17.11–26.66 0.07–0.32Mean + SD 97.5 + 11.9 4.56 + 0.6 21.621 + 2.99 0.16 + 0.08p Value <0.001 <0.001 <0.01 <0.01p* Value NS NS NS NS
Group IV (Cd intoxicated þ 7 g sodium PA)Range 99–127 5–8 13.12–21.89 0.07–0.15Mean + SD 111.5 + 11.4 6.51 + 0.8 17.35 + 2.501 0.089 + 0.02p Value <0.05 NS NS NSp* Value <0.001 <0.001 <0.01 <0.001
Group V (Cd intoxicated þ 10 g sodium PA)Range 96–125 5–7.2 13.75–24.4 0.09–0.12Mean + SD 110.5 + 10.6 6.14 + 0.6 18.241 + 3.138 0.097 + 0.009p Value <0.05 NS NS <0.02p* Value <0.001 <0.001 <0.02 <0.01
Cd: cadmium; PA: phytate; NS: not significant; T3: triiodothyronin; T4: thyroxine; TSH: thyroid stimulating hormone.aThe significance of difference was analyzed by one-way analysis of variance. p: value versus control rats (group I). p*: value versus ratsfed with Cd (group II).
Table 5. Correlation between of thyroid hormones (T3 and T4) and TSH with Cd in Cd-intoxicated rats with and withoutsodium PA.a
Parameter
T3 T4 TSH T3/T4 ratio
r p r p r p r p
Cd �0.342 <0.05 0.537 <0.001 0.508 <0.01 0.522 <0.01T3/T4 ratio �0.131 NS �0.810 <0.001 0.208 NS – –
Cd: cadmium; PA: phytate; NS: not significant; T3: triiodothyronin; T4: thyroxine; TSH: thyroid stimulating hormone.ap Value less than <0.05 is significant.
6 Toxicology and Industrial Health
at DONGGUK UNIV LIB on November 10, 2014tih.sagepub.comDownloaded from
of blood Cd in rats administrated with only Cd (group
II) was elevated as compared with the rats admini-
strated with Cd and fed with different concentrations
of sodium PA. Insignificant decrease was observed in
liver and kidney Cd concentration of rats admini-
strated with Cd and fed with different concentrations
of PA. In agreement with our result, Rimbach et al.
(1996) showed that kidney Cd concentration was
moderately increased in the PA groups. Cd represents
a dangerous environmental and industrial pollutant. It
is generally known that Cd is mainly accumulated in
the kidneys and liver of animals and humans (Toman
et al., 2005). Also, the present study showed higher
concentrations of Cd in the kidneys than in the liver.
The difference in the concentrations of Cd in these tis-
sues is explained according to the fact that Cd mostly
makes complexes with metallothionein, a protein that
binds to heavy metals for reducing their toxicity,
which separates in kidneys and accumulates in kidney
cortex. Therefore, renal damage is believed to be the
result of free Cd, which does not bind to metallothio-
nein due to localization or an excessive concentration
of Cd. The binding capacity of kidney metallothionein
is lower than that of liver metallothionein (Goyer, 1989
and Klassen, 1978). According to the results of these
authors, this tissue specific difference in binding capac-
ity may account for the sensitivity of the kidney to Cd,
and this is in agreement with the present study that
showed elevation in both liver and kidney and
increased in the kidney tissues, which in turn showed
that PA cannot chelate Cd from the liver and kidney tis-
sues. This is in agreement with the previous results of
Jarup et al. (1998) who reported that the elimination
half life of Cd is 10–30 years in the kidney and approx-
imately 5–10 years in the liver. This may be the reason
that PA ameliorates the toxic effects of Cd by a
mechanism other than metal chelation. Also, the pres-
ent results are in agreement with our previous work,
which showed that curcumin attenuated hepatorenal
toxicity induced by Cd in male rats (Afrah, 2010).
Cd-exposed rats fed with a low Ca diet exhibited a
higher liver and kidney Cd retention than Cd-exposed
rats fed with an adequate amount of Ca (Washko and
Cousins, 1977). It has been shown that the binding affi-
nity of the Ca-binding protein (CaBP) for Cd is almost
as strong as that for Ca (Bredderman and Wasser-
mann, 1974). Thus, a possible explanation could be
expected for the moderately enhanced kidney Cd reten-
tion when PA-containing diets were fed with the
slightly reduced Ca bioavailability owing to PA might
be an increase in the CaBP activity. This could be
accompanied by an increase in the mucosal Cd uptake
(Rimbach, et al., 1996).
In the previous experiment with rats (Rimbach et al.,
1995, 1996), little has been reported concerning the
influence of IP6 on Cd retention. In another study on
Japanese quails and chickens (Guillot et al., 1994,
Rambeck, 1994 and Rambeck and Walther, 1993), it
was demonstrated that IP6 enhanced Cd concentration
in the liver and kidneys. In the present study, serum Ca
concentration in rats administrated with Cd and rats
administrated with Cd and fed with different concen-
tration of sodium PA were decreased as compared to
the control rats.
Serum Fe concentration and total Fe binding capac-
ity level in rats intoxicated with Cd or rats admini-
strated with Cd and different concentrations of
sodium PA showed a significant decrease as compared
to the control rats. Small intestinal mucosal cells are
Figure 1. Control of thyroid gland in rats fed with basaldiet free of (a) sodium PA and (b) Cd-intoxicated rats(H&E, 100�). Cd: cadmium; PA: phytate; H&E: hematoxylinand eosin.
Mohamed et al. 7
at DONGGUK UNIV LIB on November 10, 2014tih.sagepub.comDownloaded from
the major sites of Fe absorption, and serum transferrin
is the major Fe carrier protein (Gibson et al., 2010;
Macgillivray et al., 1983). Fe-transferring complex
binds to the transferrin receptor at the plasma mem-
brane and gets internalized to the cells, where it is used
for heme synthesis. Cd may compete with Fe for the
same binding sites on the transferrin molecules. Ceru-
loplasmin, a copper-containing protein, plays an
important role in oxidation of Fe (II) to Fe (III) in the
cells. Cd may interfere with one of the steps of Fe
metabolism and cause anemia (Wada et al., 1979).
Exposure to Cd caused disorder in Fe metabolism
reflected changes in its bioavalability and concentra-
tion in serum and tissues as well as in its urinary excre-
tion. These observations suggest an antinutritive effect
of Cd on this bioelement (Brown et al., 2009; Moshta-
ghie et al., 1994). On the other hand, renal failure that
develops under the influence of Cd results in
erythropoietin deficiency, which may cause normo-
chromic and normocytic anemia without a proportional
increase in the reticulocytes (Hiratsuka et al., 1996;
Mackova et al., 1996 and Shagirtha and Pari, 2011).
Serum levels of T3 and T4 showed a significant
decrease and serum level of TSH and T3/T4 ratio
showed a significant increase in rats administrated with
Cd compared with the control rats. In rats admini-
strated with Cd and fed with the diet containing 3.5 g
sodium PA/kg, the serum levels of T3, T4, TSH, and
T3/T4 ratio showed significant changes compared with
the Cd group (group II), while in rats administrated
with Cd and fed with the diet containing 7 and 10 g
sodium PA/kg, serum T3 level is increased compared
with the control rats. Similarly, serum T4 and TSH lev-
els and T3/T4 ratio showed insignificant changes com-
pared with the control rats. In agreement with our
results, it was reported that serum T3 and T4 levels
Figure 2. The thyroid gland of rats intoxicated with Cd and fed with the diet containing (a) 3.5 g, (b) 7 g, and (c) 10 gsodium PA/kg(H&E, 100�). Cd: cadmium; PA: phytate; H&E: hematoxylin and eosin.
8 Toxicology and Industrial Health
at DONGGUK UNIV LIB on November 10, 2014tih.sagepub.comDownloaded from
were lowered in rats administrated with Cd (Gupta and
Kar, 1999; Nishijo et al., 1994, Pavia et al., 1997), and
the study by Curcic et al. (2011) showed lower dose of
Cd affects thyroid toxicity.
In rats administrated with Cd and rats intoxicated
with Cd and fed with the different concentrations of
PA in diet, a significant negative correlation was
detected between serum T3, serum T4, and blood Cd
concentration. A significant positive correlation was
observed between serum TSH level, T3/T4 ratio, and
blood Cd level. Increasing serum TSH level that is
observed when exposed to Cd is a response to
decreased serum T4 and T3 levels. The lack of signifi-
cant response of TSH to decreased serum T4 and T3
levels may suggest Cd interference with pituitary reg-
ulation of thyroid hormones production and secretion
(Pavia et al., 1997). Yoshizuka et al. (1991) have
speculated that the metal accumulated in the mitochon-
dria of thyroid follicular epithelial cells can inhibit the
synthesis and release of thyroid hormones influencing
the oxidative phosphorylation of these organelles.
Cd causes both structural and functional damage of
the thyroid follicular cells. Declined concentration of
serum T3 in Cd-administrated rats might be due to the
decrease in transformation rate from T4 to T3 according
to inhibition of type 1 iodothyronine 50-monodeiodi-
nase (50-D) activity, being a selenoenzyme containing
a selenocysteine residue as its active site (Chaurasia
et al., 1996; Shyam et al., 1997). Also, the probability
of Cd interference in the synthesis and/or secretion of
T4 by the thyroid follicular cells are supported by the
results of histpathological examinations. These
revealed a damaging effect of Cd on the structure of
follicular cells of the thyroid gland (Yousif and Ahmed,
2009).
In conclusion, sodium PA could reduce the hazar-
dous effects of Cd on thyroid gland. The best concen-
tration of sodium PA is 7 g/kg diet that can allow the
absorption of important inorganic metal and
decreased the hazardous effects of Cd.
Acknowledgment
Authors show their profound gratitude to Prof. Ehab M
Toson, Department of Zoology, Faculty of Science, Tanta
University, Egypt, for his assessment in the histopathologi-
cal studies of thyroid gland.
Funding
This research received no specific grant from any funding
agency in the public, commercial, or not-for-profit sectors.
References
Afrah FS (2010) Curcumin attenuated hepato-renal toxicity
induced by cadmiun in male rats. Journal of Biochemis-
try and Biotechnology 2: 73–81.
Ahn DW, Kim MY, Kim KR, and Park PS (1999) Cad-
mium binding and sodium dependent solute transport
in renal brush border membrane vesicles. Toxicology
and Applied Pharmacology 54: 212–218.
Anderson SC, Cockayne S (1993) Anderson SC, Cockayne S,
and Saunders WB (eds) Electrolytes concepts and applica-
tions. Philadelphia, PA: W.B. Saunders, pp. 397.
Bianco AC, Salvatore D, Gereben B, Berry MJ, and Larsen
PR (2002) Biochemistry, cellular and molecular biology
and physiological roles of the iodothyronine selenodeio-
dinase. Endocrine Reviews 23: 38–89.
Bredderman PJ, Wassermann RH (1974) Chemical compo-
sition, affinity for calcium, and some related properties
of the vitamin D dependent calcium-binding protein.
Biochemistry 13: 1687–1694.
Bremner I, Campbell JK (1978) Effect of copper and zinc
status on susceptibility to cadmium intoxication. Envi-
ronmental Health Perspectives 25: 125–128.
Briet F, Twomey C, and Jeejeebhoy KN (2003) Effect of
malnutrition and short-term refeeding on peripheral blood
mononuclear cell mitochondrial complex I activity.
American Journal of Clinical Nutrition 77: 1304–1311.
Brown KH, Hambidge KM, and Ranum P (2010) Zinc for-
tification of cereal flours: current recommendations and
research needs. Food and Nutrition Bulletin 31:
S62–S74.
Brown KH, Peerson JM, Baker SK, and Hess SY (2009)
Preventive zinc supplementation among infants, pre-
schoolers, and older prepubertal children. Food and
Nutrition Bulletin 30: S12–S40.
Brus R, Szkilnik R, Nowak P, Oswiecimska J, Kasperska
A, Sawczuk K, et al. (1999) Effect of lead and ethanol,
consumed by pregnant rats, on behavior of their grown
offsprings. Pharmacology Reviews and Communica-
tions 10: 175–186.
Callahan JH, Cook KO (1982) Modified CMB methods of
iron estimation in serum. Analytical Chemistry 54: 59–62.
Chaurasia S, Gupta P, Kar A, and Maiti PK (1996) Free
radical mediated membrane perturbation and inhibition
of type-I iodothyronine 50- monodeiodinase activity by
lead and cadmium in rat liver homogenate. Biochemistry
and Molecular Biology International 39: 765–770.
Curcic M, Jacevic V, Stankovic S, Jankovic S, Durgo K,
Vucinic S, et al. (2011) Effects of BDE 209 and cad-
mium mixture on thyroid hormone levels in rats. Toxi-
cology Letters 205: S180–S300.
Mohamed et al. 9
at DONGGUK UNIV LIB on November 10, 2014tih.sagepub.comDownloaded from
Czajk-Narins DM (1986) Nutrition, vitamins and trace ele-
ment. In: Tietz NW (ed) Text Book of Clinical Chemis-
try. Philadelphia, PA: W.B. Saunders, pp. 1116.
Drury RAB, Wallington EA (1980) Preparation and Fixa-
tion of Tissues in Carleton’s Histological Technique. 4th
ed. New York, NY: Oxford University Press, pp. 36–56.
Gibson RS, Bailey KB, Gibbs M, and Ferguson EL (2010)
A review of phytate, iron, zinc, and calcium concentra-
tions in plant-based complementary foods used in low-
income countries and implications for bioavailability.
Food and Nutrition Bulletin 31: S134–S146.
Goyer RA (1989) Non-metallothionein-bound cadmium in
the Pathogenesis of cadmium nephrotoxicity in the rat.
Toxicology and Applied Pharmacology 101: 232–244.
Guillot I, Birzer D, and Rambeck WA (1994) The enzyme
phytase and its influence on the retention of cadmium in
rats and in Japanese quails. Revue de Medecine Veteri-
naire 145: 387–398.
Gupta P, Kar A (1999) Cadmium induced thyroid dysfunction
in Chicken: hepatic type 1 iodothyronine 5’-monodeiodi-
nase activity and role of lipid peroxidation-India. Com-
parative Biochemistry and Physiology Part A 123: 39–44.
Gupta V, Gill KD (2000) Influence of ethanol on lead dis-
tribution and biochemical changes in rats exposed to
lead. Alcohol 20: 9–17.
Hayter J (1980) Trace element implications for nursing.
Journal of Advanced Nursing 5: 91–101.
Hiratsuka H, Katsuta O, Toyota N, Tsuchitani M, Ume-
mura T, and Marumo F (1996) Chronic cadmium
exposure-induced renal anemia in ovariectomized rats.
Toxicology and Applied Pharmacology 137: 228–236.
Hollander CS, Nihei N, Burday SZ, Mitsuma T, Shenkman
L, and Blum M (1972) Clinical and laboratory observa-
tions in cases of triiodothyronine toxicosis confirmed by
radioimmunoassay. Lancet 1: 609–611.
Hu H (2000) Exposure to metals. Primary Care 27:
983–996.
Jarup L, Berglund M, Elinder CG, Nordberg G, and Vahter
M (1998) Health effects of cadmium exposure: a review
of the literature and risk estimate. Scandinavian Journal
of work, Environmental and Health 24: 1–51.
Katsumi Y, Naoko S, Michiko S, Toshiro S, Shintaro S,
Kaoru Y, et al. (1984) Effect of cadmium on outer ring
monodeiodination by rat liver. Environment Research
42: 400–405.
Klassen CD (1978) Effect of metallothionein on hepatic
disposition of metals. American Journal of Physiology
234(1978): E47–E53.
Lonnerdal B (2002) Phytic acid–trace element (Zn, Cu,
Mn) interactions. International Journal of Food Science
and Technology 37(7): 749–758.
Macgillivray RTA, Mendez E, Shewale JG, Sinha SK,
Lineback ZSJ, and Brew K (1983) The primary structure
of human serum transferrin. Journal of Biological
Chemistry 258: 3545–3553.
Mackova NO, Lenikova S, Fedorocko P, and Brezani P
(1996) Effects of cadmium on haemopoiesis in irra-
diated and nonirradiated mice: relationship to the num-
ber of circulating blood cells and haemopoiesis.
Physiological Research 45: 101–106.
Madapallimattam AG, Jeejeebhoy KN, and Law L (2002)
Effect of hypoenergetic feeding on muscle oxidative
phosphorylation and mitochondrial complex I-IV
activities in rats. Journal of Clinical Nutrition 76:
1031–1039.
Minihan AM, Rimbach G (2002) Iron absorption and the
iron binding and antioxidant properties of IP6. Interna-
tional Journal of Food Science and Technology 37:
741–748.
Mitra E, Ghosh AK, Ghosh D, Mukherjee D, Chattopad-
hyay A, Dutta S, et al. (2012) Protective effect of aqu-
eous Curry leaf (Murraya koenigii) extract against
cadmium-induced oxidative stress in rat heart. Food and
Chemical Toxicology 50: 1340–1353.
Moshtaghie AA, Taghikhani M, and Sandughchin M
(1994) Cadmium interaction with iron metabolism, in
vitro and in vivo studies. Journal of Islamic Academy
of Sciences 7(3): 145–150.
National Research Council (NRC) (1995) Nutrient
Requirements of Laboratory Animals. 4th ed. Washing-
ton DC: National Academy press.
Nishijo M, Nakagawa H, Morikawa Y, Tabata M, Senma
M, Miura K, et al. (1994) Study of thyroid hormone lev-
els of inhabitants of the cadmium-polluted Kakehashi
river-Department of Public Health, Kanazawa Medical
University, Ishikawa, Japan. Nippon Eiseigaku Zasshi
49: 598–605.
Pavia MAJr, Paier B, Noli MI, Hagmuller K, and Zanino-
vich AA (1997) Evidence suggesting that cadmium
induced anon-thyroidal illness syndrome in the rat.
Journal of Endocrinology 154(1): 113–117.
Petering HG (1978) Some observations on the interaction
of zinc, copper, and iron metabolism in lead and cad-
mium toxicity. Environmental Health Perspectives 25:
141–145.
Pollard FH, Marun JV (1956) The spectrophotometric
determination of the alkaline-earth metals with murex-
ide, eriochrome black T and with o-cresolphthalein
complexone. Analyst 81: 348.
Prince HP, Ramsden DB (1977) A new theoretical descrip-
tion of the binding of thyroid hormones by serum pro-
teins. Clinical Endocrinology 7: 307–324.
10 Toxicology and Industrial Health
at DONGGUK UNIV LIB on November 10, 2014tih.sagepub.comDownloaded from
Rambeck WA (1994) Beeinflussung des carry overs von
cadmium in der Nahrungskette. Proceedings of the
Nutrition Society 2: 23–29.
Rambeck WA, Walther P (1993) Nutritional significance
of phytic acid and phytase In: Enzymes in animal Nutri-
tion, Proceedings of the 1st International Symposium,
Kartause, Ittingen, Switzerland, pp. 199–201.
Razniewska G, Trzcinka-Ochocka M (1995) The use of fla-
meless ASS for determining lead and cadmium in blood
and cadmium, copper, nickel and chromium in urine.
Medycyna Pracy 46: 347–358.
Rimbach G, Pallauf J (1997) Cadmium accumulation, zinc
status, and mineral bioavailability of growing rats fed
diets high in zinc with increasing amounts of phytic
acid. Biological Trace Element Research 57: 59–70.
Rimbach G, Pallauf J, Brandt K, and Most E (1995) Effect
of phytic acid and microbial phytase on Cd accumula-
tion, Zn status and apparent absorption of Ca, P, Mg,
Fe, Zn, Cu and Mn in growing rats. Annals of Nutrition
and Metabolism 39: 361–370.
Rimbach G, Pallauf J, and Walz OP (1996) Effect of micro-
bial phytase on cadmium accumulation in pigs. Archives
of Animal Nutrition 49: 279–286.
Rose HE, Quarterman J (1984) Effects of dietary phytic
acid on lead and cadmium uptake and depletion in rats.
Environment Research 35(2): 482–489.
Shagirtha K, Pari L (2011) Hesperetin, a citrus flavonone,
attenuates cadmium-induced nephrotoxicity in rat. Bio-
medicine and Preventive Nutrition 1: 139–145.
Shyam SC, Sunanda P, and Kar A (1997) Lead inhibits type-
I iodothyronine 50-monodeiodinase in the Indian rock
pigeon Columba livia: a possible involvement of essential
thiol groups. Journal of Bioscience 22: 247–254.
Strbak V, Benicky J, Macho L, Jezova D, and Nikodemova
M (1998) Four week ethanol intake decreases food
intake and body weight but does not affect plasma lep-
tin, corticosterone and insulin levels in pubertal rats.
Metabolism 47: 1269–1273.
Toman R, Massanyi P, Lukac N, Ducsay L, and Golian J
(2005) Fertility and content of cadmium in Pheasant
(Phasianus colchicus) following cadmium intake in
drinking water. Exotoxicology and Environmental
Safety 62: 112–117.
Tsao GT, Zheng Y, Lu J, and Gong CS (1997) Adsorp-
tion of heavy metal ions by immobilized phytic acid.
Applied Biochemistry and Biotechnology 63:
731–741.
Urani C, Melchioretto P, Canevali C, Morazzoni F, and
Gribaldo L (2007) Metallothionein and hsp70 expres-
sion in HepG2 cells after prolonged cadmium exposure.
Toxicology In Vitro 21: 314–319.
Urbano G, Lpez-Jurado M, Aranda P, Vidal-Valverde C,
Tenorio E, and Porres J (2000) The role of phytic acid
in legumes: antinutrient or beneficial function? Journal
of Physiology and Biochemistry 56: 283–294.
Wada HG, Hass PH, and Sussman HH (1979) Transfer-
rin receptor in human placental brush border mem-
branes. Journal of Biological Chemistry 254:
12629–12635.
Washko PW, Cousins R (1977) Role of dietary calcium and
calcium-binding protein in cadmium toxicity in rats.
Journal of Nutrition 107: 920–928.
Yoshizuka M, Mori N, Hamasakik Y, Harak M, Doi Y,
Umezu Y, et al. (1991) Cadmium toxicity in the thyroid
gland of pregnant rats. Experimental and Molecular
Pathology 55: 97–104.
Yousif AS, Ahmed AA (2009) Effects of cadmium (Cd)
and lead (Pb) on the structure and function of thyroid
gland. African Journal of Environmental Science and
Technology 3: 78–85.
Mohamed et al. 11
at DONGGUK UNIV LIB on November 10, 2014tih.sagepub.comDownloaded from
Top Related