Protective effect of ebselen on aflatoxin B1-induced cytotoxicity in primary rat hepatocytes

Recent studies have shown that aflatoxin B1 enhances reactive oxygen species formation and causes oxidative damage, which may ultimately contribute to the cytotoxicity and carcinogenic effect of aflatoxin B1. Ebselen, 2-phenyl-1,2-benzoisoseleazol-3(H)-one, a synthetic seleno-organic compound has been shown to possess glutathione peroxidase-like activity and free radical scavenging ability. Thus present study was designed to investigate the protective effect of ebselen on aflatoxin B1-induced cytotoxicity in primary rat hepatocytes. Aflatoxin B1-induced cytotoxicity and lipid peroxidation were determined by lactate dehydrogenase leakage and malondialdehyde generation, respectively. Intracellular reactive oxygen species level was measured using the fluorescent probe 2',7'-dichlorofluorescin diacetate, and the intracellular reduced glutathione concentration was determined with a fluorometric method. Ebselen was found to display a dose-dependent protective effect on lactate dehydrogenase leakage and malondialdehyde generation caused by aflatoxin B1 exposure. The results also demonstrate that ebselen efficiently inhibits the intracellular reactive oxygen species formation in aflatoxin B1-treated hepatocytes in a dose and time-dependent manner. It was also noted that ebselen was able to increase the intracellular reduced glutathione concentration, both in the control and in aflatoxin B1-treated hepatocytes. The protection of ebselen against aflatoxin B1 cytotoxicity, however, was not affected by lowering the concentration of intracellular reduced glutathione. The overall data indicate that ebselen possesses a potent protective effect against aflatoxin B1-induced cytotoxicity, and the main mechanism involved in the protection may be its strong capability in inhibiting intracellular reactive oxygen species formation and preventing oxidative damage.     

Protective effect of Indigofera aspalathoides against CCl4-induced hepatic damage in rats

The alcoholic extract of stem of Indigofera aspalathoides was evaluated for its antihepatotoxic activity against CCl(4)-induced hepatic damage in rats. The activity was evaluated by using biochemical parameters, such as serum glutamate pyruvate transaminase (SGPT), serum glutamate oxaloacetate transaminase (SGOT), alkaline phosphatase (ALP), total bilirubin and gama glutamate transpeptidase (GGTP). The histopathological changes of liver sample were compared with respective control. The extract showed remarkable hepatoprotective effect.     

Bacterial lipopolysaccharide exposure augments aflatoxin B(1)-induced liver injury.

Bacterial endotoxin (lipopolysaccharide; LPS) given to animals in large doses results in pronounced, midzonal liver injury. Exposure to smaller, non-injurious doses of LPS augments the toxicity of certain hepatotoxicants. This study was conducted to delineate the development of injury in a rat model of augmentation of aflatoxin B(1) (AFB(1)) hepatotoxicity by LPS. At large doses (i.e., > 1 mg/kg, ip), AFB(1) administration resulted in pronounced injury to the periportal regions of the liver. Male, Sprague-Dawley rats (250-350 g) were treated with 1 mg AFB(1)/kg, ip or its vehicle (0.5% DMSO/saline) and 4 h later with either E. coli LPS (7.4 x 106 EU/kg, iv) or its saline vehicle. Liver injury was assessed 6, 12, 24, 48, 72, or 96 h after AFB(1) administration. Hepatic parenchymal cell injury was evaluated as increased alanine aminotransferase (ALT) and aspartate aminotransferase (AST) activities in serum and from histologic examination of liver sections. Biliary tract alterations were evaluated as increased concentration of serum bile acids and activities of gamma-glutamyltransferase (GGT), alkaline phosphatase (ALP), and 5'-nucleotidase (5'-ND) in serum. At all times and for all markers, injury in rats treated with either AFB(1) or LPS alone was absent or modest. In the AFB(1)/LPS cotreated group, hepatic parenchymal cell injury was pronounced by 24 h and had returned to control values by 72 h. The injury began in the periportal region and spread midzonally with time. Furthermore, changes in serum markers indicative of biliary tract alterations were evident by 12 h and had returned to control values by 72 h. Thus, the nature of the hepatic lesions suggested that LPS potentiated the effects of AFB(1) on both parenchymal and bile duct epithelial cells.     

Iron exclusion from aflatoxin B1-induced hepatocellular carcinoma in rats

Mixed-cell hepatocellular adenocarcinomas, induced by aflatoxin B1 (AFB1) in weanling rats, were allowed to develop for 18 months; age- and sex-matched controls were maintained. After 18 months, treated and control rats were administered iron dextran (ID), intraperitoneally (i.p.) as Nonemic. No gross or microscopic lesions were observed in control animals, while hepatic tumors were observed grossly in all AFB1-treated rats. Areas of apparently normal tissue, in histologic sections from control animals and in non-tumor sites of sections from AFB1-treated animals, were deeply stained for iron, both in endothelial cells and in hepatocytes, as visualized by Perls iron stain. Varying degrees of exclusion of stainable iron material were noted in histologic sections of lesions from AFB1-treated rats, as were alterations in endothelial cell staining characteristics. Iron staining clearly demonstrates the presence of varying cell populations within the induced mixed cell hepatocellular adenocarcinoma.     

Effect of caloric restriction on hepatic nuclear DNA damage in male Fischer 344 rats treated with aflatoxin B1.

Caloric restriction is known to reduce chemically-induced tumor incidence in laboratory animals. The effect is believed to be mediated in part by modification of hepatic drug metabolism, including both phase I and phase II enzymes. Using aflatoxin B1 (AFB1) as a model carcinogen, we studied the effect of caloric restriction on the modification of rat liver nuclear DNA by AFB1 and DNA damage due to the formation of apurinic sites from the AFB1-DNA adduct removal process. Caloric restriction reduced the metabolic activation of AFB1 which resulted in a decrease of AFB1-DNA binding by more than 50%. The results of the study of the effect of caloric restriction on the AFB1-induced DNA strand breakage assayed by the alkaline unwinding technique showed that caloric restriction protected the formation of apurinic sites from the AFB1-DNA adducts and reduced the double strand DNA breakages by 1.3-2.5-fold. Thus, the lower initial AFB1-DNA binding and less DNA damage, presumably by the less apurinic sites formed during the depurination process of AFB1-DNA adducts, contributed to the protective effect of caloric restriction.     

Genome-wide miRNA-profiling of aflatoxin B1-induced hepatic injury using deep sequencing

Aflatoxin B1 is a potent carcinogen which can induce** hepatocellular carcinoma (HCC) in mammals. Though microRNAs are known to play important roles in tumorigenesis, the functional complexity of microRNAs in AFB1-induced hepatocellular tumorigenesis has not yet been elucidated. Here, we applied Illumina deep sequencing technology for high-throughput profiling of microRNA in rat liver tissue before and after treatment with aflatoxin B1. Analysis of mature miRNAs from different arms of pre-miRNAs allowed us to identify the predominant form of miRNA. We studied the differential expression profile of miRNAs in two libraries, identifying several cancer-related microRNAs which exhibit abnormal expression. KEGG analysis indicated that predicted target genes of differentially expressed miRNAs are involved in cancer-related pathways. Bioinformatic analysis predicted 16 potential novel miRNAs. Our work provides new insights at the miRNA level into AFB1-induced hepatic injury which may lead to HCC.     

Inhibitory effect of CDA-II, a urinary preparation, on aflatoxin B(1)-induced oxidative stress and DNA damage in primary cultured rat hepatocytes.

The effects of CDA-II (cell differentiation agent II; a urinary preparation) on both aflatoxin B(1) (AFB(1))-induced cell injury and DNA damage were investigated using cultured rat hepatocytes. CDA-II was able to suppress both the lipid peroxidation and lactate dehydrogenase leakage induced by AFB(1). Glutathione (GSH) depletion by AFB(1) was replenished by CDA-II treatment. Under these experimental conditions, CDA-II enhanced the activity of GSH peroxidase, but not GSH S-transferase. By evaluation of unscheduled DNA synthesis, CDA-II reduced AFB(1)-induced DNA damage in hepatocyte cultures. These findings suggest that CDA-II can inhibit cytotoxicity of AFB(1) through enhancing the activity of GSH peroxidase and preventing GSH depletion.     

Effects of intermittent exposures of aflatoxin B(1) on hepatic and testicular glutathione S-transferase in rats

Glutathione S-transferase (GST) plays a major role in the detoxification of the potent hepatocarcinogen aflatoxin B(1) (AFB(1)). This study evaluated the effects of intermittent exposures to AFB(1) on hepatic and testicular GST in rats. Male Fischer 344 rats were fed diets containing AFB(1) (0, 0.01, 0.04, 0.4 and 1.6 ppm) intermittently at 4-week intervals up to 20 weeks. The control animals were fed an AFB(1)-free NIH-31 diet. Rats consuming diets with 0.01 ppm AFB(1) did not show the induction of hepatic or testicular GST activity. Intermittent exposures to AFB(1) at concentrations of 0.04-1.6 ppm significantly increased the GST activities. The increase of the enzyme activity was proportional to the dose and length of AFB(1) exposure.     

Protective effects of baicalein and wogonin against benzo[a]pyrene- and aflatoxin B(1)-induced genotoxicities.

To evaluate the protective effects of baicalein and wogonin against benzo[a]pyrene- and aflatoxin (AF) B(1)-induced toxicities, the effects of these flavonoids on the genotoxicities and oxidation of benzo[a]pyrene and AFB(1) were studied in C57BL/6J mice. Baicalein and wogonin reduced benzo[a]pyrene and AFB(1) genotoxicities as monitored by the umuC gene expression response in Salmonella typhimurium TA1535/pSK1002. Baicalein added in vitro decreased liver microsomal benzo[a]pyrene hydroxylation (AHH) activity with an ic(50) of 33.9 +/- 1.4 microM at 100 microM benzo[a]pyrene. Baicalein also inhibited AFQ(1) and AFB(1)-epoxide formation from AFB(1) (50 microM) oxidation (AFO) with ic(50) values of 22.8 +/- 1.4 and 5.3 +/- 0.8 microM, respectively. However, the in vitro inhibitory effects of wogonin on AHH and AFO activities in liver microsomes were less than those of baicalein as inhibition by 500 microM wogonin was only about 51-65%. Treatment of mice with liquid diets containing 5 mM baicalein and wogonin resulted in 22 and 49% decreases in hepatic AHH activities, respectively. Baicalein treatment resulted in 39 and 32% decreases in AFQ(1) and AFB(1)-epoxide formation from liver microsomal AFO, respectively. Wogonin treatment resulted in 39 and 47% decreases in AFQ(1) and AFB(1)-epoxide formation, respectively. A 1-week pretreatment with wogonin significantly decreased hepatic DNA adduct formation in mice treated with 200 mg/kg of benzo[a]pyrene via gastrogavage. These in vitro and in vivo effects suggested that baicalein and wogonin might have beneficial effects against benzo[a]pyrene- and AFB(1)-induced hepatic toxicities and that wogonin had a stronger protective effect in vivo.     

Spermatotoxic effect of aflatoxin B(1) in the albino mouse.

With the background that the foodborne mycotoxin aflatoxin B(1) (AFB(1)) could be toxic to the male reproductive mechanism in man as well as wild and domestic animals, the present study was aimed at finding the effect of AFB(1) on sperm. The Swiss albino mouse was the test animal. AFB(1,) suspended in corn oil and ethanol (95:5, v/v), was administered intraperitoneally to 90-day-old mice at a daily dose of 50 microg/kg body weight for 7, 15, 35 and 45 days. The analysis consisted of fertility testing and counts, motility and abnormalities of the cauda epididymidal sperm, adopting light- as well as electron-microscopy. The fertility of the treated mice was reduced drastically. Sperm concentration in the epididymis and sperm motility decreased whereas sperm abnormalities increased. In particular, sperm abnormalities like two axonemes in a common cytoplasm, sticking together of heads/tails, etc., were noted. A higher percentage of cauda epididymidal spermatozoa than in the control mice retained the cytoplasmic droplet (CD) and such retention was dependent on the duration of the treatment. Spermatozoa retaining the CD were inhibited in motility. Sperm CD of AFB(1)-treated mice contained electron-dense spherical inclusions, which are hypothesized as lipid inclusions produced from the lamellae through the spherical vesicles of the CD. The results indicate disruption of the spermatogenic as well as androgenic compartments of the testis by AFB(1). The results also reflect an alteration of epididymal function towards the post-testicular sperm maturation process by AFB(1).     

Comparative effects of curcumin and resveratrol on aflatoxin B1-induced liver injury in rats

Aflatoxin B₁ is a potent hepatotoxic and hepatocarcinogenic mycotoxin. Lipid peroxidation and oxidative DNA damage are the principal manifestations of aflatoxin B₁-induced toxicity that could be counteracted by antioxidants. Many plant constituents have been reported to prevent liver damage associated with lipid peroxidation. In this study, curcumin (polyphenolic antioxidant purified from turmeric) and resveratrol (polyphenol obtained from grapes) were evaluated for possible protection against liver injury induced by aflatoxin B₁ in rats. Adult male Fischer rats were divided into six groups including untreated control, curcumin control (200 mg/kg BW), resveratrol control (10 mg/kg BW) and aflatoxin B₁ (25 μg/kg BW). Other two groups were administered either curcumin or resveratrol along with aflatoxin B₁. The study was carried out for 90 days. At the end of the experiment period, blood and tissue samples were collected from the animals before they were killed. Livers were collected for histopathologic studies and fixed in 10% buffered formalin solution. Serum was used for estimation of alanine aminotransferase (ALT), aspartate aminotransferase (AST) and γ-glutamyl transferase (γ-GT) enzymes. The lipid peroxidation, reduced glutathione (GSH), superoxide dismutase (SOD), catalase (CAT) and glutathione peroxidase (GSH-Px) were estimated in liver homogenates. The results revealed that aflatoxin B₁ administration caused liver damage as indicated by statistically significant (P < 0.05) increase in serum ALT, AST and γ-GT levels. In addition, there were general statistically significant reductions in the activities of GSH, SOD, CAT, GSH-Px, and an increase in lipid peroxidation in the liver of aflatoxin B₁-treated group compared to the untreated control group. Curcumin showed a significant hepatoprotective activity by lowering the levels of serum marker enzymes, lipid peroxidation and elevating the levels of GSH, SOD, CAT and GSH-Px. However, resveratrol failed to protect from the aflatoxin B₁-induced liver injury. These findings suggest that curcumin but not resveratrol has a hepatoprotective effect against aflatoxin B₁-induced liver injury.     

Effect of ethanol on hepatotoxicity and hepatic DNA-binding of aflatoxin B1 in rats

The hepatocarcinogen aflatoxin B1 is converted to reactive metabolites that bind covalently to cellular macromolecules. These metabolites may also react with glutathione, resulting in the formation of glutathione conjugates and detoxication of the reactive metabolite. When rats were pretreated with ethanol by gastric intubation at a dose of 100 mmol/kg, 6 hr (the time of maximal GSH depletion) before the administration of aflatoxin B1, the covalent binding of 8,9-epoxide-aflatoxin B1 to DNA in vivo was increased by 47% and the hepatotoxicity was also potentiated. However, the covalent binding was not increased by pretreatment with ethanol 18 hr (time with approximately normal GSH levels) before administration of the toxin, and no potentiation of hepatotoxicity was observed. Pretreatment with a non-toxic dose of ethanol had no effects on the activity of glutathione S-transferase and glutathione peroxidase. These results suggest that the depletion of GSH and the increased formation of DNA-adduct from the liver constitute an important mechanism for the potentiation of aflatoxin B1-induced hepatotoxicity by ethanol.     

Lipopolysaccharide augments aflatoxin B(1)-induced liver injury through neutrophil-dependent and -independent mechanisms.

Exposure to small, noninjurious doses of the inflammagen, bacterial endotoxin (lipopolysaccharide, LPS) augments the toxicity of certain hepatotoxicants including aflatoxin B(1) (AFB(1)). Mediators of inflammation, in particular neutrophils (PMNs), are responsible for tissue injury in a variety of animal models. This study was conducted to examine the role of PMNs in the pathogenesis of hepatic injury after AFB(1)/LPS cotreatment. Male, Sprague-Dawley rats (250-350 g) were treated with either 1 mg AFB(1)/kg, ip or its vehicle (0.5% DMSO/saline), and 4 h later with either E. coli LPS (7. 4 x 10(6) EU/kg, iv) or its saline vehicle. Over a course of 6 to 96 h after AFB(1) administration, rats were killed and livers were stained immunohistochemically for PMNs. LPS resulted in an increase in PMN accumulation in the liver that preceded the onset of liver injury. To assess if PMNs contributed to the pathogenesis, an anti-PMN antibody was administered to reduce PMN numbers in blood and liver, and injury was evaluated. Hepatic parenchymal cell injury was evaluated as increased alanine aminotransferase (ALT) and aspartate aminotransferase (AST) activities in serum and from histologic examination of liver sections. Biliary tract alterations were evaluated as increased concentration of serum bile acids and activities of gamma-glutamyltransferase (GGT), alkaline phosphatase (ALP), and 5'-nucleotidase (5'-ND) in serum. Neutrophil depletion protected against hepatic parenchymal cell injury caused by AFB(1)/LPS cotreatment but not against markers of biliary tract injury. This suggests that LPS augments AFB(1) hepatotoxicity through two mechanisms: one of which is PMN-dependent, and another that is not.     

Protective effects of coffee diterpenes against aflatoxin B1-induced genotoxicity: mechanisms in rat and human cells.

The coffee-specific diterpenes cafestol and kahweol (C + K) have been reported to be anticarcinogenic in several animal models. Proposed mechanisms involve a co-ordinated modulation of several enzymes responsible for carcinogen detoxification, thus preventing reactive agents interacting with critical target sites. To address the human relevance of the chemoprotective effects of C + K against aflatoxin B(1) (AFB1) genotoxicity observed in rat liver, and to compare the mechanisms of protection involved in both species, animal and human hepatic in vitro test systems were applied. In rat primary hepatocytes, C + K reduced the expression of cytochrome P450 CYP 2C11 and CYP 3A2, the key enzymes responsible for AFB1 activation to the genotoxic metabolite aflatoxin B1-8,9 epoxide (AFBO). In addition, these diterpenes induced significantly GST Yc2, the most efficient rat GST subunit involved in AFBO detoxification. These effects of C + K resulted in a marked dose-dependent inhibition of AFB1-DNA binding in this rat in vitro culture system. Their relevance in humans was addressed using liver epithelial cell lines (THLE) stably transfected to express AFB1 metabolising cytochrome P450s. In these cells, C + K also produced a significant inhibition of AFB1-DNA adducts formation linked with an induction of the human glutathione S-transferase GST-mu. Altogether, these results suggest that C + K may have chemoprotective activity against AFB1 genotoxicity in both rats and humans.     

Effect of aflatoxin B1 on hepatic drug-metabolizing enzymes in female rats. Interaction with a contraceptive agent

1. The effect of a contraceptive on aflatoxin B1 toxicity has been studied in female rats treated for 15 consecutive days with repeated doses of aflatoxin (0.40 mg/kg/day), norethindrone (0.60 mg/kg/day) and ethynylestradiol (0.012 mg/kg/day). 2. Increases occurred in hepatic microsomal cytochrome P-450 content (31%), and in the activities of epoxide hydrase (77%), UDP-glucuronyltransferase (67%) and gamma-glutamyltransferase (78%). 3. Aflatoxin alone caused a 22% increase in GSH S-epoxide transferase activity, whereas the contraceptive given alone or combined with aflatoxin increased the hepatic reduced glutathione. 4. The effect of aflatoxin plus contraceptive was not additive. 5. The effects caused by aflatoxin and the contraceptive were similar, and the contraceptive (depending on its progestogen/estrogen ratio), may modify aflatoxin toxicity by increasing the drug-metabolizing enzyme activities and the concentration of hepatic glutathione.     

Modulating role of Semecarpus anacardium L. nut milk extract on aflatoxin B(1) biotransformation.

As part of a substantial effort to curtail the adverse health effects posed by aflatoxin B(1), studies have been conducted to elucidate the possible mechanism for the anticarcinogenic action of Semecarpus anacardium nut extract against aflatoxin B(1)-induced hepatocellular carcinoma. Rats are monitored for levels of urinary, serum and liver biomarkers, namely, unmetabolised aflatoxin B(1), and its metabolites aflatoxin M(1), and aflatoxin Q(1), over the course of 2 weeks with nut extract therapy following a single-exposure to aflatoxin B(1). Due to the administration of nut extract, the excretion of unmetabolised aflatoxin B(1) was increased in day 1 urine when compared with rats without drug treatment. In serum and liver which were collected on day 16 and the rest of periodical urine samples showed aflatoxin B(1) and its metabolites in undetectable levels. The nut extract administration induced cytochrome P(450), glutathione, and glutathione-S-transferase levels in liver homogenates of aflatoxin B(1)-treated rats. These data seem to indicate that anticarcinogenic action by Semecarpus anacardium nut extract is possibly via suppression of aflatoxin B(1)activation and through interaction with microsomal-activating components. Previous evidence from this laboratory about the potency of Semecarpus anacardium nut extract against aflatoxin B(1)-induced hepatocellular carcinoma together with the present results suggest that extremely effective therapeutic protection can be achieved by this drug against aflatoxin B(1)-mediated ill effects.     

Protective activity of different hepatic cytosolic glutathione S-transferases against DNA-binding metabolites of aflatoxin B1

To evaluate the role of glutathione S-transferase (GST) isoenzymes in induced resistance of hepatocytes to aflatoxin B1 (AFB1), we compared DNA protective activities of different hepatic cytosol preparations and purified GSTs from normal rats, rats exposed to different polychlorinated biphenyls (PCBs), and rats with carcinogen-induced hepatocellular neoplasms, with cytosols or purified GSTs from mouse, rainbow trout, and human livers. These comparisons were performed in an in vitro assay for [3H]AFB1-DNA binding after activation by rat liver microsomes. Cytosol and S-hexylglutathione-affinity-purified GST preparations from livers of mice consistently had strong protective activity against AFB1-DNA binding. The majority of this activity was dependent on the presence of reduced glutathione (GSH) but some GSH-independent protection was observed in mouse hepatic cytosol, but not in purified GST preparations. We found that all of the GSH-dependent DNA-protective activity in mouse liver eluted as a single GST isoenzyme by hydroxyapatite chromatography. Preparations of cytosol and purified GSTs from normal rat liver, rainbow trout liver, and human liver had much less AFB1-specific DNA protective activity than GSTs found in mouse liver preparations. Cytosol from rats with carcinogen-generated liver neoplasms and livers induced with 3,3',4,4'-tetrachlorobiphenyl and 2,2',4,4',5,5'-hexachlorobiphenyl had more GST activity toward CDNB than cytosol from normal rat liver. When equivalent units of GST activity (CDNB) were compared, there was little difference observed between the DNA-protective activities of PCB-induced and normal rat liver cytosols, yet cytosol from rat liver neoplasms was more protective. Purified GST-P (7-7), the GST isoenzyme most induced in carcinogen-generated rat liver neoplasms, was not protective when added at protein concentrations found to be protective for total GSTs isolated from these neoplasms. These studies demonstrate that the resistance of mouse liver to AFB1 can be explained primarily by a single constitutive GST isoenzyme (YaYa or 4-4) with a relatively high activity toward DNA-binding metabolites of AFB1. GST isoenzymes with such high specific DNA protective activity against AFB1 metabolites were not evident in human, rat, or rainbow trout liver or in PCB-induced or neoplastic rat liver preparations.     

四味肝泰纳米颗粒对黄曲霉毒素B1诱发大鼠肝癌的影响

目的:探讨四味肝泰纳米颗粒对黄曲霉毒素B1诱发大鼠肝癌模型的药效作用及其作用机理。方法:采用血清常规肝功检测、抗氧化实验、Bax/Bcl-2和TNF-α免疫组织化学分析以及HE染色方法对黄曲霉毒素B1诱发大鼠肝癌模型进行检测。结果:各剂量四味肝泰纳米颗粒(2.03,1.01,0.5 mg.kg-1,ig)均可有效降低大鼠肝脏损伤程度,并能通过提高抗氧化酶表达来降低过氧化脂质水解物丙二醛含量;同时可以促使Bax过量表达,导致大鼠体内TNF-α含量升高,促使癌细胞凋亡,从而发挥抗肝癌作用。结论:四味肝泰纳米颗粒对黄曲霉毒素B1诱发的大鼠肝癌具有显著疗效,这与其抗氧化作用有关。     

Du-Zhong (Eucommia ulmoides Oliv.) leaves inhibits CCl4-induced hepatic damage in rats.

The protective effects of water extract of Du-Zhong (Eucommia ulmoides Oliv.) leaves (WEDZ) and its active compound (protocatechuic acid; PCA) on liver damage were evaluated by carbon tetrachloride (CCl4)-induced chronic hepatotoxicity in rats. Wistar rats were orally treated with WEDZ (0.1, 0.5, and 1.0 g/kg bw) or PCA (0.1 g/kg bw) with administration of CCl4 (0.5 ml/rat, 20% CCl4 in olive oil) for 28 consecutive days. It showed that CCl4-treated rats increased the relative organ weights of liver and kidney. CCl4-induced rats liver damage and significantly (p<0.05) increased the GOT, GPT, LDH and ALP levels in serum as compared with the control group. Treatment with WEDZ or PCA could decrease the GOT, GPT, LDH and ALP levels in serum when compared with CCl4-treated group. CCl4-treated rats also significantly (p<0.05) decreased the GSH content in liver and trolox equivalent antioxidant capacity (TEAC) in serum whereas increased (p<0.05) MDA content in liver as compared with the control group. Treatment with WEDZ or PCA also significantly (p<0.05) increased the GSH content and significantly (p<0.05) decreased the MDA content in liver. Administration of WEDZ or PCA could increase the activities of GPx, GRd and GST in liver. Liver histopathology showed that WEDZ or PCA reduced the incidence of liver lesions including hepatic cells cloudy swelling, lymphocytes infiltration, cytoplasmic vacuolization, hepatic necrosis and fibrous connective tissue proliferated induced by CCl4 in rats. The data suggest that oral administration with WEDZ for 28 consecutive days significantly decrease the intensity of hepatic damage induced by CCl4 in rats.     

Protective effect of N-acetylcysteine against radiation induced DNA damage and hepatic toxicity in rats

The present study was designed to evaluate the radioprotective effect of N- acetylcysteine (NAC) on gamma-radiation induced toxicity in hepatic tissue in rat. The cellular changes were estimated using malondialdehyde (MDA, an index of lipid peroxidation), superoxide dismutase (SOD), glutathione peroxidase (GSHPx), reduced glutathione (GSH), and total nitrate/nitrite (NO(x)) as markers of hepatic oxidative stress in rats following gamma-irradiation. The DNA damage was determined by agarose gel electrophoresis. To achieve the ultimate goal of this study, 40 adult rats were randomly divided into 4 groups of 10 animals each. Group I was injected intraperitoneally with saline solution for 7 consecutive days and served as control group. Group II was irradiated with a single dose of 6Gy gamma-radiation. Group III was daily injected with NAC (1g/kg, i.p.) for 7 consecutive days. Group IV received a daily i.p. injection of NAC (1g/kg, i.p.) for 7 consecutive days and 1h after the last dose, rats were irradiated with a single dose (6Gy) gamma-radiation. The animals were sacrificed after 24h. DNA damage was observed in tissue after total body irradiation with a single dose of 6Gy. Malondialdehyde and total nitrate/nitrite were increased significantly whereas the levels of GSH and antioxidant enzymes were significantly decreased in gamma-irradiated group. Pretreatment with NAC showed a significant decrease in the levels of MDA, NO(x) and DNA damage. The antioxidant enzymes increased significantly along with the levels of GSH. Moreover, histopathological examination of liver tissues confirmed the biochemical data. Thus, our results show that pretreatment with N-acetylcysteine offers protection against gamma-radiation induced cellular damage.