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published online 15 October 2012Toxicol Ind HealthMemisogullari and Ismail Hamdi Kara

Ayhan Saritas, Hayati Kandis, Davut Baltaci, Umran Yildirim, Halil Kaya, Ali Karakus, Serdar Colakoglu, RamazanN-Acetyl cysteine and erdosteine treatment in acetaminophen-induced liver damage

  

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Article

N-Acetyl cysteine and erdosteinetreatment in acetaminophen-inducedliver damage

Ayhan Saritas1, Hayati Kandis1, Davut Baltaci2,Umran Yildirim3, Halil Kaya4, Ali Karakus5,Serdar Colakoglu6, Ramazan Memisogullari7 andIsmail Hamdi Kara2

AbstractObjective: This study is aimed to investigate the efficacy of erdosteine usage in acetaminophen-induced liverdamage and to compare it with N-acetyl cysteine (NAC) in the treatment and prevention of liver toxicity dueto overdose of acetaminophen.

Methods: The rats were separated into the following six groups of seven rats each: control group;acetaminophen (1 g/kg, orally); acetaminophen (1 g/kg, orally) þ erdosteine (150 mg/kg/day, orally); acet-aminophen (1 g/kg, orally) þ NAC (140 mg/kg loading dose, followed by 70 mg/kg, orally); NAC (140 mg/kgloading dose, followed by 70 mg/kg, orally); erdosteine (150 mg/kg/kg, orally), subsequently. In all the groups,potential liver injuries were evaluated using biochemical and hematological analyses, oxidant–antioxidantparameters and histopathological parameters.

Results: In acetaminophen-treated group, levels of alanine aminotransferase (ALT), aspartate aminotrans-ferase (AST), total oxidant status (TOS) in the blood, prothrombin time (PT) and international normalizedratio (INR) were significantly increased when compared with controls. However, total antioxidant capacity(TAC) and glutathione (GSH) levels were decreased in group treated with acetaminophen, when comparedwith control group. Levels of AST, ALT and TOS, PT and INR were decreased in groups treated with NACand erdosteine after acetaminophen administration, but the levels of TAC and GSH were increased.Histopathological improvements were observed in the groups treated with NAC and erdosteine afteracetaminophen administration.

Conclusion: The present study demonstrated that, in the prevention of liver damage induced byacetaminophen intoxication, an early treatment with a single dose of erdosteine was beneficial instead of NACadministration.

KeywordsLiver toxicity, total oxidant status, total antioxidant capacity, poisoning, paracetamol

1 Department of Emergency Medicine, Duzce University School of Medicine, Duzce, Turkey2 Department of Family Medicine, Duzce University School of Medicine, Duzce, Turkey3 Department of Pathology, Duzce University School of Medicine, Duzce, Turkey4 Department of Emergency Medicine, Harran University School of Medicine, Sanliurfa, Turkey5 Department of Emergency Medicine, Mustafa Kemal University School of Medicine, Hatay, Turkey6 Department of Anatomy, Duzce University School of Medicine, Duzce, Turkey7 Department of Biochemistry, Duzce University School of Medicine, Duzce, Turkey

Corresponding author:Hayati Kandis, Department of Emergency Medicine, Duzce University School of Medicine, Duzce, TurkeyEmail: hayatikandis@yahoo.com

Toxicology and Industrial Health1–9© The Author(s) 2012Reprints and permissions:sagepub.co.uk/journalsPermissions.navDOI: 10.1177/0748233712463780tih.sagepub.com

Introduction

Acetaminophen is a commonly used analgesic and

antipyretic agent. However, when taken in overdose,

it can cause hepatic necrosis and even death in

humans and experimental animals (Bessems and Ver-

meulen, 2001; Maddrey, 2005). The intake of aceta-

minophen in therapeutic doses is safe, but more than

140 mg/kg in a single use or more than 7.5 g/day for

long-term use in adults can lead to intoxication.

Adults who take acetaminophen in overdose mostly

do so when attempting suicide, whereas acetamino-

phen overdose in children is primarily accidental

(Bartlett, 2004; Hung and Nelson, 2004; Mladenovic

et al., 2009).

Acetaminophen is easily absorbed and it peaks in

circulation within 2 h of therapeutic doses. Its

amounts of 20–46% and 40–67% are metabolized in

the liver by sulfation and glucorunidation, respec-

tively. At least 5% is absorbed through the kidneys.

A small amount of acetaminophen is oxidized to a

toxic reactive metabolite N-acetyl-p-benzoquinone

imine (NAPQI) by cytochrome P450 enzymes. This

metabolite is detoxified by glutathione (GSH) in the

liver, and then it is removed from the body through

conversion to nontoxic mercapturate (Hung and

Nelson, 2004; James et al., 2003). However, the

mechanisms of sulfation and glucorunidation become

insufficient in cases of overdose. A large amount of

acetaminophen is metabolized by cytochrome P450

enzymes, and eventually the source of GSH is

exhausted. Also, a large amount of reactive and toxic

metabolite NAPQI is produced from the overdose of

acetaminophen oxidized by cytochrome P450

enzymes, but it is not detoxified because the source

of GSH is exhausted (Hung and Nelson, 2004; James

et al., 2003; Kuvandik et al., 2008).

N-Acetyl cysteine (NAC) is used as a standard ther-

apy to prevent and decrease acetaminophen-induced

hepatotoxicity (Hung and Nelson, 2004; Prescott

et al., 1977; Rumack, 2002; Yagmurca et al., 2007).

There are only a few clinical and experimental studies

in the literature in which the use of erdosteine for

hepatotoxicity caused due to drugs or toxic agents was

noted (Selcoki et al., 2007; Yagmurca et al., 2007;

Yesildag et al., 2009).

In this study, we aimed to investigate the efficacy

of erdosteine usage in acetaminophen-induced liver

damage and to compare it with NAC usage in the

treatment and prevention of liver toxicity due to over-

dose of acetaminophen.

Materials and methods

Animals and experimental procedures

Experiments were performed on 42 adult female

Wistar albino rats (210–240 g). The rats were cared

for in accordance with the Guide for the Care and

Use of Laboratory Animals. They were housed in

silent rooms with a 12-hour light–dark cycle (7:00

a.m.–7:00 p.m.). The Ethics Committee of the Izzet

Baysal University approved the study protocols

(2011–2014).

In the present study, we used the methodology of

the previously published study of Kandis et al.

(2011). The rats were separated into the following six

groups of seven rats each:

Group 1: control group;

Group 2: acetaminophen group; acetaminophen

(1 g/kg, orally);

Group 3: erdosteine treatment group; erdosteine at

a loading dose (150 mg/kg, orally) is given 2 h

after acetaminophen (1 g/kg, orally), followed

by a single daily dose of erdosteine (150 mg/kg,

orally) for 3 days;

Group 4: NAC treatment group; NAC at a loading

dose (140 mg/kg, orally) is given 2 h after

acetaminophen (1 g/kg, orally), followed by a

maintenance dose of NAC (70 mg/kg, orally)

given 17 times, 4 h apart;

Group 5: NAC control group; NAC given at a

loading dose (140 mg/kg, orally), followed by

a maintenance dose of NAC (70 mg/kg, orally)

given 17 times, 4 h apart;

Group 6: erdosteine control group; erdosteine given

at a single dose (150 mg/kg, orally) daily for 3 days

Solutions of acetaminophen, NAC and erdos-

teine were distilled with water. Then, these solu-

tions were given orally via nasogastric tube.

Three days after treatment, all the rats were

anesthetized by administering ketamine hydro-

chloride (50 mg/kg, intramuscularly) (Ketalar;

Parke Davis, Eczacibasi, Istanbul, Turkey) and

xylazine hydrochloride (3 mg/kg, intramuscularly)

(Rompun; Bayer AG, Leverkusen, Germany). For

the operation procedure, rats were put into a supine

position. Laparotomy was performed through a

midline incision for each rat. Then, liver tissue

samples and blood samples were taken from all

rats. At the end of the process, all the rats were

killed via exsanguination method.

2 Toxicology and Industrial Health

Oxidant and antioxidant parameters

Blood samples were drawn into the tubes containing

gel without anticoagulants and were centrifuged at

2000g for 15 min. Serum was divided into portions

and kept in clean tubes.

Serum kept separately to carry out the GSH test

was deproteinated. For this step, 5 g of metaphospho-

ric acid was dissolved in 50 mL of water and vor-

texed, after which 200 mL of serum was mixed with

200 mL of metaphosphoric acid solution. This pre-

paration was kept at room temperature for 5 min and

then centrifuged at 2000g for 4 min. The deprotei-

nated and other serum portions were separated.

Deproteinated portions were assayed with GSH,

whereas other serum portions were used for oxidants

and antioxidants assay. All the other serum portions

were kept at �80�C until the test time.

The GSH test was performed with the commercial

enzymatic assay method (Cayman Inc., Ann Arbor,

Michigan, USA) using GSH reductase for the quantifi-

cation of GSH. In this method, the sulfhydryl group of

GSH reacted with 5,50-dithio-bis-2-nitrobenzoic acid

(DTNB) and produced a yellow 5-thio-2-nitrobenzoic

acid (TNB). The rate of TNB production was directly

proportional to the GSH concentration in the sample.

Triethanolamine solution (4 M) of 10 mL was prepared

on the day of assay was added to the 200-mL samples

and then was vortexed. After the samples were diluted

with MES (0.4 M 2-(N-morpholino) ethanesulphonic

acid, 0.1 M phosphate, 2 mM EDTA, pH 6.0) buffer

in a 1:3 proportion, the standards were prepared accord-

ing to the directions of standard prospectus. To the

wells, 50-mL standards or 50-mL samples were added,

and the plate was covered with a cover that accompanies

the kit. In this step, an assay mixture containing MES

buffer (11.25 mL), GSH cofactor mixture (0.45 mL),

GSH enzyme mixture (2.1 mL), water (2.3 mL) and

GSH DTNB (0.45 mL) was prepared according to the

directions of prospectus. Fresh assay mixture of

150 mL was placed in each well, and the plate was cov-

ered and incubated on an orbital shaker in the dark for 25

min. At the 25th minute, an assay was performed at 414

nm with a Bio-Rad 680 Microplate Reader (Bio-Rad

Laboratories, Inc., USA).

A total oxidant status (TOS) assay was performed

with the Rell Assay kits (Rell-Assay kits, Gaziantep,

Turkey) developed by Erel (2005). In this assay method,

oxidants present in the sample oxidized the ferrous ion

to ferric ion. The ferric ion made a colored complex with

chromogen in an acidic medium. The color intensity,

which can be measured spectrophotometrically, was

related to the total amount of oxidant molecules present

in the sample. After the stabilized stock solution was

diluted, it was deionized with water 40 times and

1000 mL of reagent-1 was mixed with 150 mL of stan-

dard or sample. First, the absorbance was read at 530

nm. Prochromogen solution of 50 mL was added and

incubated at room temperature for 10 min. After this

process, a second absorbance was read at 530 nm.

The following formulae were used for calculation

TOS ¼ D Absorbance sample=D Absorbance standardð Þ� standardvalue

D Absorbance sample ¼ second absorbance sample

� first absorbance sample

D Absorbance standard ¼ second absorbance standard

� first absorbance standard

Standard value: 20 mmol hydrogen peroxide

Equiv./L

Total antioxidant capacity (TAC) was based on the

inhibition of 2,20-azino-di-(3-ethylbenzthiazolin

sulphonate) (ABTS) oxidation to ABTS by metmyo-

globin, using the Cayman kit (Cayman Inc.). On assay

day, samples were dissolved and diluted in 1:20 ratio

with assay buffer. Resulted standards were prepared

according to the prospectus. Trolox standard of

10 mL or samples of 10-mL were put into wells, and

10 mL metmyoglobin and 150 mL chromogen solu-

tions were added. Without delay, 40-mL of 441-mM

antioxidant assay hydrogen peroxide was added for

the reaction to run. The plate was covered and

incubated for 5 min on mixture. It was measured at

405 nm by using a Bio-Rad 680 Microplate Reader.

Biochemical and hematological analyses

Alanine aminotransferase (ALT) and aspartate ami-

notransferase (AST) were measured with an Abbott

Architect C8000 (Abbott Diagnostics, Japan) clinical

chemistry auto analyzer using a kinetic method.

Prothrombin time (PT) and international normal-

ized ratio (INR) were assayed in a compact automatic

coagulation analyzer, and complete blood count was

performed with a CELL-DYN 3700 SL analyzer

(Abbott Diagnostics, Chicago, Illinois, USA).

Saritas et al. 3

Histopathological evaluation

For histopathological evaluation, the liver tissues

were dissected and fixed in Zenker solution for

24 h, dehydrated in ethanol series, cleared and

embedded in paraffin. The paraffin sections were cut

into 5-mm-thick slices and stained with hematoxylin

and eosin for light microscopic evaluation. The sec-

tions were viewed and photographed using an Olympus

light microscope (Olympus BX51, Olympus Optical

Co. Ltd, Tokyo, Japan) with an attached photograph

machine (Olympus E-330, Olympus Optical Co. Ltd,

Tokyo, Japan). A total of 10 slides were prepared from

each liver. All the sections were evaluated for the

degree of portal inflammation, necrosis, vacuolar

degeneration, sinusoidal dilatation and vascular con-

gestion. Each liver slide was examined, and the sever-

ity of the changes observed was scored using a

damage-rating scale of ‘none’ (�), ‘mild’ (þ), ‘mod-

erate’ (þþ) and ‘severe’ (þþþ). An experienced

pathologist made the histopathological evaluation.

Statistical analysis

Whole measured information was uploaded and

assessed with SPSS 15.0 software (SPSS Inc., Chicago,

Illinois, USA). All the groups showed normal distribu-

tion, so parametric statistical methods were used to ana-

lyze the data. A one-way analysis of variance test was

performed, and post hoc multiple comparisons were

done with the Bonferroni method. The chi-square (Fish-

er’s exact) test was used to categorize the data analysis.

The Spearman’s rho test was used for the correlation

analysis. Results were presented as means + SEM. A

p < 0.05 was considered to be statistically significant.

Results

Oxidant and antioxidant parameters

The level of serum TOS was found to be significantly

higher in group 2 (acetaminophen group) when com-

pared with the other groups (p < 0.0001). The TOS level

was markedly decreased in group 3 (erdosteine treat-

ment group) and group 4 (NAC treatment group), but

no significant differences were noted between these

groups. The levels of GSH and TAC were significantly

lower in group 2 when compared with other groups

(Table 1). There were no significant differences in TAC

levels in groups 3 or 4, and these levels were similar in

both the groups. However, although significant differ-

ences in the GSH levels were not detected between

groups 3 and 4, the GSH level in group 4 was found to

be increased (p < 0.77) when compared with group 3.

Serum AST, ALT and platelet levels

Levels of serum AST and ALT along with INR and

PT values were found to be significantly higher and

longer, respectively, in group 2 compared with other

groups (p < 0.0001; Table 1), but they were

Table 1. Results of biochemical and hematological analyses

Parameters

Groups

p valuebGroup 1 Group 2 Group 3a Group 4a Group 5 Group 6

AST (IU/L) 50.9 + 3.4 409.1 + 136.2 77.4 + 10.3 63.1 + 4.7 57.4 + 9.5 56.6 + 10.0 <0.0001ALT(IU/L) 41.9 + 5.0 266.9 + 60.5 58.1 + 6.6 52.0 + 6.6 52.3 + 6.9 48.1 + 7.5 <0.0001PLT (�1000/

mm3)322.3 + 713 306.9 + 84.4 322.7 + 70.4 341.1 + 70.0 331.9 + 60.9 337.1 + 72.7 >0.05

INR 0.91 + 0.44 2.74 + 0.6 1.15 + 0.14 1.08 + 0.96 0.97 + 0.36 0.95 + 0.30 <0.0001PT (s) 12.4 + 0.4 28.0 + 4.8 14.8 + 1.3 14.1 + 1.0 13.0 + 0.4 12.8 + 0.3 <0.0001TOSc (mmol/L) 3.16 + 1.23 17.54 + 2.6 6.83 + 1.45 6.91 + 1.91 3.3 + 1.18 3.2 + 1.89 <0.0001TACd (mmol/L) 1.13 + 0.15 0.77 + 0.40 0.92 + 0.48 0.90 + 0.67 1.18 + 0.35 1.14 + 0.20 <0.0001GSHe (mmol/L) 1.22 + 0.22 0.76 + 0.06 0.99 + 0.16 1.13 + 0.15 1.22 + 0.32 1.23 + 0.39 0.004

AST: aspartate aminotransferase; ALT: alanine aminotransferase; PLT: platelet; INR: international normalized ratio; PT: prothrombintime; TOS: total oxidant status; TAC: total antioxidant capacity; GSH: glutathione.aComparison of group 3 vs. group 4, there were no statistically significant difference in any parameter (p > 0.05).bComparison of group 2 vs. other groups, there were statistically significant difference (p < 0.0001) in all the parameters except PLT(p > 0.05).cComparisons of group 2 vs. group 1 (p ¼ 0.007); group 2 vs. group 5 (p ¼ 0.002) and group 2 vs. group 6 (p ¼ 0.006).dComparisons of group 2 vs. group 1 (p ¼ 0.004); group 2 vs. group 5 (p ¼ 0.006) and group 2 vs. group 6 (p ¼ 0.001).eComparisons of group 2 vs. group 1 (p ¼ 0.018); group 2 vs. group 5 (p ¼ 0.008) and group 2 vs. group 6 (p ¼ 0.014).

4 Toxicology and Industrial Health

Figure 1. Histopathological appearance in hepatocytes. (a) Group 1: Normal histopathological appearance in hepatocytesand zone 3 area (HE: �200). (b) Group 2: Vacuolar degeneration in hepatocytes (bold black arrow), zone 3 area and focalnecrosis in liver parenchyma (red arrow). Mild inflammation in portal area (thin black arrow), sinusoidal dilatation (bluearrow) and vascular congestion (green arrow) (HE: �400–�200). (c) Group 3: Vacuolar degeneration in hepatocytes(bold black arrow), focal necrosis in hepatocytes (red arrow) and vascular congestion (thin black arrow) (HE: �200).(d) Group 4: Mild vacuolar degeneration (black arrow) and vascular congestion (red arrow) (HE:�400). (e) and (f) Groups5 and 6: Normal histopathological appearance in hepatocytes in zone 3 and portal area (HE: �200). HE: hematoxylin andeosin.

Saritas et al. 5

significantly decreased in groups 3 and 4 (p < 0.0001).

However, significant differences between groups 3

and 4 were not detected (p > 0.05). Besides being sta-

tistically nonsignificant, the levels of ALT and AST

from group 4 were closer to those from group 1 when

compared with such levels from group 3. No signifi-

cant differences were observed for platelet levels

among the groups.

Histopathological findings

On histopathological evaluation of the liver with a light

microscope, morphological changes such as portal

inflammation, necrosis, vacuolar degeneration, sinusoi-

dal dilatation and vascular congestion were observed in

group 2 compared with group 1 (Figure 1(a) and (b) and

Table 2). Although portal inflammation, necrosis,

vacuolar degeneration, sinusoidal dilatation and vascu-

lar congestion were observed in group 3, those morpho-

logical changes were significantly declined when

compared with group 2 (p < 0.0001; Figure 1(c)). In

group 4, mild vacuolar degeneration and vascular con-

gestion were observed, and cellular injury was scant and

almost similar with group 1 (Figure 1(d)). Hepatocytes

in group 4 displayed better morphological changes

when compared with group 2 (p < 0.0001). Group 5

(NAC control group) and group 6 (erdosteine control

group) displayed well-defined hepatocytes and par-

enchymal morphology (Figure 1(e) and (f)).

Discussion

NAC is a precursor for cysteine and is the most common

agent used in the prevention of liver damage in patients

who have ingested a potentially toxic dose of acetami-

nophen (Isik et al., 2006; Rumack, 2002; Yagmurca

et al., 2007). NAC prevents NAPQI from early binding

to hepatic macromolecules, but it is suggested that NAC

decreases neutrophil infiltration and increases microcir-

culation and oxygen transportation to tissues, thus

removing acetaminophen from tissues (Hung and Nel-

son, 2004). NAC has been tried in the treatment of var-

ious liver injuries because of its known antioxidant

properties (Baniasadi et al., 2010; Cetinkaya et al.,

2006; Ji et al., 2009; Zwingmann and Bilodeau, 2006).

Initially, it is given either orally or intravenously at a

Table 2. Results of histopathological examination

Parameter Degree

Groups

p valueaGroup 1 Group 2a Group 3 Group 4 Group 5 Group 6

Vascular congestionb None 7 0 2 4 7 7 <0.0001Mild 0 0 5 3 0 0Moderate 0 5 0 0 0 0Severe 0 2 0 0 0 0

Sinusoidal dilatationb None 7 0 1 3 7 7 <0.0001Mild 0 0 6 4 0 0Moderate 0 2 0 0 0 0Severe 0 5 0 0 0 0

Vacuolar degenerationb None 7 0 2 3 7 7 <0.0001Mild 0 0 5 4 0 0Moderate 0 5 0 0 0 0Severe 0 2 0 0 0 0

Necrosisb None 7 0 3 5 7 7 <0.0001Mild 0 0 4 2 0 0Moderate 0 0 0 0 0 0Severe 0 7 0 0 0 0

Portal inflammationb None 7 0 2 3 7 7 <0.0001Mild 0 0 5 4 0 0Moderate 0 2 0 0 0 0Severe 0 5 0 0 0 0

Total None 7 7 7 7 7 42

aComparison of group 2 vs. other groups; statistically significant difference in portal inflammation, necrosis, vacuolar degeneration,sinusoidal dilatation and vascular congestion (p < 0.0001).bComparison of group 3 vs. group 4; no statistically significant difference in portal inflammation, necrosis, vacuolar degeneration,sinusoidal dilatation and vascular congestion (p > 0.05).

6 Toxicology and Industrial Health

dose of 70 mg/kg per 4 h for 17 times, following its load-

ing dose of 10 mg/kg (Dienstag, 2008; Hung and Nel-

son, 2004).

Erdosteine, like NAC, is a mucolytic and antioxi-

dant drug. It contains two blocked thiol groups (Isik

et al., 2006; Koc et al., 2005; Kuvandik et al., 2008;

Moretti and Marchioni, 2007). Erdosteine probably

protects from acetaminophen-induced hepatotoxicity

by preventing free-radical–damaging cascades and

oxidant-radical release and through its prevention of

proinflammatory processes (Dechant and Noble,

1996; Fadillioglu et al., 2003; Gazzani et al., 1989).

Several studies have addressed the antioxidant effects

of erdosteine (Fadillioglu et al., 2003; Gazzani et al.,

1989; Sogut et al., 2004; Terzi et al., 2004). In differ-

ent animal experiments, erdosteine was studied in dif-

ferent doses (Isik et al., 2006; Kuvandik et al., 2008;

Selcoki et al., 2007).

In the literature, the only study that has addressed

the usage of erdosteine in the prevention of

acetaminophen-induced liver damage is an animal

experimental study conducted by Kuvandik et al.

(2008). A literature search did not reveal any study

that has compared the efficacy between NAC and

erdosteine in the decrease of acetaminophen-

induced liver damage. Several animal studies and

case reports have addressed liver toxicity due to a

high dose of acetaminophen (Kuvandik et al., 2008;

Newsome et al., 2010).

Reactive oxygen and nitrogen species play an

important role in the development of

acetaminophen-induced hepatotoxicity (James et al.,

2003; Michael et al., 1999; Nakae et al., 1990). The

initial step of this toxicity is the cytochrome P450

enzymes’ metabolism of acetaminophen to the reac-

tive intermediate NAPQI (Dahlin et al., 1984). When

the source of hepatic GSH falls under 30%, NAPQI

begins to bind to hepatic macromolecules. Liver dam-

age then develops and eventually leads to hepatic

necrosis. Injured hepatocytes secrete liver enzymes

such as AST and ALT into circulation. The measure-

ment of liver enzymes is a reliable indicator for clin-

ical status of the patient (Blakely and McDonald,

1995; Hung and Nelson, 2004). In our study, the

increase in the levels of AST and ALT and the INR

and the development of centrilobular necrosis upon

histopathological evaluation after toxic acetamino-

phen administration were the indicators of liver

damage.

Several studies have demonstrated that acetamino-

phen may induce oxidative injury, including tissue

lipid peroxidation, enzyme inactivation, changes in

the nonenzymatic and enzymatic antioxidant defense

system of cells as well as changes in GSH status

(Hung and Nelson, 2004; Isik et al., 2006; Kuvandik

et al., 2008; Mladenovic et al., 2009). GSH is an

important protective molecule and its sulfhydryl part

conjugates with electrophilic and highly reactive

NAPQI to be detoxified. In the event of overdose of

a toxic substance, GSH is depleted and detoxification

is limited (Geiger and Howard, 2007; Josephy, 2005).

Because of its antioxidant properties, NAC has

been suggested to decrease liver damage by reducing

reactive metabolites that have been raised due to the

overdose of acetaminophen, although these metabo-

lites’ actions are not clearly known in acetaminophen

intoxication. Moreover, it is known that NAC restores

the GSH source (Hung and Nelson, 2004; Kandis

et al., 2011; Mladenovic et al., 2009).

In the present study, the GSH level declined signif-

icantly in group 2 but was increased in group 4. This

indicated that NAC had a positive effect on the GSH

level. When compared with group 2, the restoration of

the GSH level in group 3 demonstrated that the source

of GSH was less used because of the antioxidant

effect of erdosteine.

Several studies have demonstrated that antioxidant

parameters were reduced and oxidant parameters

were increased after oxidative injury from acetamino-

phen intoxication (Isik et al., 2006; Kuvandik et al.,

2008; Mladenovic et al., 2009). In our study, the TOS

level was significantly increased, but the TAC level

was decreased in group 2 when compared with group

1, which indicated oxidative injury. The increase in

the TAC level and the decrease in the TOS level in

groups 3 and 4 indicated that erdosteine and NAC

increase antioxidants but decrease oxidant capacity.

Acetaminophen-induced liver damage increases

the levels of liver enzymes such as AST and ALT.

Also, an elevation in bilirubin and INR levels can

be seen in addition to metabolic acidosis, coagulopa-

thy, jaundice, renal insufficiency, hepatic encephalo-

pathy, myocardial pathology and coma. In our

study, a marked increase in AST, ALT and INR levels

in group 2 compared with group 1 demonstrated a sig-

nificant correlation to liver damage. The decline in

AST, ALT and INR levels in groups 3 and 4 in con-

trast to group 2 was an important indicator that erdos-

teine and NAC were effective in treating

acetaminophen-induced hepatotoxicity. Besides no

significant difference has been noted between groups

3 and 4, it was noteworthy that the levels of ALT,

Saritas et al. 7

AST and INR were similar to those in group 1. How-

ever, no changes in the number of platelets among

groups were considered because platelet numbers

were not influenced in the early period.

In the study by Kuvandik et al. (2008) in rats with

acetaminophen-induced liver damage, they used 150

and 300 mg/kg of erdosteine in the treatment and

demonstrated that the liver status improved to a similar

degree at both the doses. In our study, a dosage of 150

mg/kg of erdosteine led to a decrease in liver damage.

Studies have also reported that acetaminophen

causes liver damage characterized by hemorrhagic

centrilobular necrosis in both people and animals (Isik

et al., 2006; Kuvandik et al., 2008; Valentovic et al.,

2004). In the event of an acetaminophen overdose,

hepatic GSH falls under 30%. Then, NAPQI starts

binding to other hepatocytes, and the hepatic necrosis

eventually develops. In the hepatic lobule, cyto-

chrome P450 enzymes are usually found in hepato-

cytes around the hepatic vein and also in small

amounts in hepatocytes around the portal vein

(Kuvandik et al., 2008; Valentovic et al., 2004).

Therefore, acetaminophen-induced liver damage

displays characteristic centrilobular necrosis. Our

results were consistent with those from studies that

have reported the development of characteristic cen-

trilobular necrosis in liver damage after administering

1 mg/kg of acetaminophen (Bauer et al., 2000;

Kuvandik et al., 2008).

In our study, portal inflammation, necrosis, vacuo-

lar degeneration, sinusoidal dilatation and vascular

congestion were more marked in group 2. Also, cen-

trilobular necrosis caused cytoplasmic changes and

sinusoidal narrowing around the central vein. Marked

inflammation in group 2 could be a result of chemo-

tactic factors secreted from hepatocytes (Kuvandik

et al., 2008). In addition, fewer microscopic changes

were observed in groups 3 and 4 when compared with

group 2. Erdosteine and NAC significantly sup-

pressed the inflammatory response due to acetamino-

phen. Notwithstanding, portal inflammation, necrosis,

vacuolar degeneration, sinusoidal dilatation and vas-

cular congestion in group 4 were more similar to

group 1. No significant differences were observed

between groups 3 and 4 in the prevention of liver

damage. However, treatment with NAC is still first-

line therapy because there are several similarities with

group 1 regarding biochemical parameters and histo-

pathological findings.

The limitations of our study include (1) it reflects

results of short-term duration, such as 3 days of

investigation, and (2) it lacks results of long-term fol-

low-up.

In conclusion, the present study demonstrated that,

in the prevention of liver damage induced by acetami-

nophen intoxication, early treatment with a single

dose of erdosteine was beneficial instead of NAC

administration. Because of the usefulness of erdos-

teine and its consistency among patients, we consider

it an alternative treatment in liver damage. However,

as previously mentioned, our study did not cover data

for long-term treatment. Therefore, further investiga-

tions regarding those subjects are needed.

Funding

The authors thank the Emergency Physicians Association

of Turkey for the financial support and its valued

contribution.

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