Gel entrapment culture of rat hepatocytes for investigation of tetracycline-induced toxicity

This paper aimed to explore three-dimensionally cultured hepatocytes for testing drug-induced nonalcoholic steatohepatitis. Gel entrapped rat hepatocytes were applied for investigation of the tetracycline-induced steatohepatitis, while hepatocyte monolayer was set as a control. The toxic responses of hepatocytes were systematically evaluated by measuring cell viability, liver-specific function, lipid accumulation, oxidative stress, adenosine triphosphate content and mitochondrial membrane potential. The results suggested that gel entrapped hepatocytes showed cell death after 96 h of tetracycline treatment at 25 μM which is equivalent to toxic serum concentration in rats, while hepatocyte monolayer showed cell death at a high dose of 200 μM. The concentration-dependent accumulation of lipid as well as mitochondrial damage were regarded as two early events for tetracycline hepatotoxicity in gel entrapment culture due to their detectability ahead of subsequent increase of oxidative stress and a final cell death. Furthermore, the potent protection of fenofibrate and fructose-1,6-diphosphate were evidenced in only gel entrapment culture with higher expressions on the genes related to β-oxidation than hepatocyte monolayer, suggesting the mediation of lipid metabolism and mitochondrial damage in tetracycline toxicity. Overall, gel entrapped hepatocytes in three-dimension reflected more of the tetracycline toxicity in vivo than hepatocyte monolayer and thus was suggested as a more relevant system for evaluating steatogenic drugs.     

The course of CCl4 induced hepatotoxicity is altered in mGSTA4-4 null (-/-) mice

Glutathione S-transferases (GSTs) play a key role in cellular detoxification of environmental toxicants through their conjugation to glutathione (GSH). Recent studies have shown that the alpha-class GSTs also provide protection against oxidative stress and lipid peroxidation (LPO). GSTA4-4 is a member of a sub group of the alpha-class GSTs. It has been shown to metabolize 4-hydroxynonenal (4-HNE) with high catalytic efficiency through its conjugation to glutathione (GSH) and has been suggested to be a major component of cellular defense against toxic electrophiles such as 4-HNE generated during LPO. Since the hepatotoxicity of carbon tetrachloride (CCl(4)) has been suggested to be due to the generation of free radicals leading to membrane LPO, the present studies were designed to compare hepatotoxicity of CCl(4) in GSTA4-4 null (-/-) and wild type (+/+) mice. The results show that administration of a single dose of CCl(4) (1 ml/kg i.p.) resulted in time dependent hepatotoxicity in both -/- and +/+ mice; the extent of cellular damage by serum enzymes suggests that progression was more rapid in -/- mice, although injury was similar by 24 h. Histopathologic examination showed similar degrees of centrilobular necrosis by 24 h but much greater surrounding degenerative change, including cellular swelling, disarray, and vacuolization, in the liver of -/- mice. As expected -/- mice did not show any expression of mGSTA4-4; after CCl(4) a compensatory increase in the activities of total GST activity was noted at 24 h. Major alterations in other antioxidant enzymes was not observed. 4-HNE levels in the liver of -/- mice were about four-fold higher than in +/+ mice, suggesting a positive correlation between 4-HNE levels and the altered course of CCl(4) hepatotoxicity. These studies suggest that GSTA4-4 is an important component during the early stages (1-6 h) of cellular defense against oxidative stress and LPO although, it is not effective in protecting against the ultimate degree of overall cell injury.     

Evaluation of ambrein and epicoprostanol for their antioxidant properties: protection against adriamycin-induced free radical toxicity.

Ambrein and epicoprostanol were evaluated for their antioxidant potential in vitro by chemiluminescence (CL), as well as in vivo using lipid peroxides and glutathione levels as indicators in liver tissue of rats treated with adriamycin (doxorubicin) a well known free radicals producing drug. In the in vitro test, the inhibition in CL by ambrein was dose dependent. Both the high concentrations of ambrein (20-40 microg/ml) inhibited CL response significantly (P<0.05 and P<0.01, respectively) when compared to control. Similarly two low concentrations (5-20 microg/ml) of epicoprostanol inhibited CL significantly (P<0.001 and P<0.01, respectively) in comparison of DMSO control. The high concentration (40 microg/ml) of epicoprostanol behaved exceptionally and caused an increase in CL response that was more than control and significantly (P<0.001) higher than both the low concentrations. In the in vivo studies adriamycin treatment significantly (P<0.05) increased malondialdehyde (MDA) and decreased non-protein sulfhydryl (NP-SH) contents in the liver tissue of mice after 5 days treatment. Ambrein (25 and 50 mg/kg) treatment as a solo therapy at both the dose levels significantly (P<0.001) decreased MDA contents in the liver tissue. On the other hand, in the combined treatment the high dose effectively prevented any rise in MDA contents and it remained around the levels of ambrein alone. In the same experiment, adriamycin declined NP-SH contents significantly (P<0.001). Ambrein alone at both the dose levels caused a decline (P<0.01) in NP-SH contents when compared to adriamycin group. But in the combined treatment this decline in NP-SH was significantly (P<0.05) different from adriamycin alone. In the experiments dealing with epicoprostanol, adriamycin treatment increased MDA contents significantly (P<0.05) that declined significantly (P<0.001) with epicoprostanol (10- or 20mg/kg) treatment. In the same experiment co-treatment with adriamycin prevented any rise in MDA contents significantly (P<0.001) as it was observed in adriamycin alone group. Although, this treatment failed to prevent any decline in NP-SH contents either alone or in combination with adriamycin. Epicoprostanol itself had the comparative declining effect on the contents of NP-SH as seen in adriamycin group. From the results of our experiments it seems that ambrein at all concentrations behaves like antioxidant in in vitro studies but the same time it decreased NP-SH contents in vivo accompanied by a decline in MDA contents. Whereas, epicoprostanol at two low concentrations had a decline in CL indicating a possible antioxidant potential but the high concentration increased CL showing a tendency towards oxidant prospective. However, in animal studies it has shown a clear protection against adriamycin induced free radical damage.     

Protective effect of aqueous extract of Perilla frutescens on tert-butyl hydroperoxide-induced oxidative hepatotoxicity in rats.

The leaves of perilla [Perilla frutescens (L.) Britt. var. japonica (Hassk.) Hara] are often used in Asian gourmet food. The object of this study was to evaluate the protective effects of an aqueous extract of perilla leaves on the tert-butyl hydroperoxide (t-BHP)-induced oxidative injury observed in rat livers. The treatment of the hepatocytes with the perilla leaf extract (PLE) significantly reversed the t-BHP-induced cell cytotoxicity and lipid peroxidation. In addition, PLE exhibited ferric-reducing antioxidant power and 2,2-diphenyl-1-picrylhydrazyl free radical scavenging activities. The in vivo study showed that the pretreatment with PLE (1000 or 3000 mg/kg) for 5 days before a single dose of t-BHP (i.p.; 0.2 mmol/kg) significantly lowered the serum levels of aspartate aminotransferase and alanine aminotransferase, reduced the indicators of oxidative stress in the liver, such as the glutathione disulfide content and lipid peroxidation level in a dose-dependent manner, and remarkably increased the activity of hepatic gamma-glutamylcysteine synthetase. Histopathological examination of the rat livers showed that PLE reduced the incidence of liver lesions induced by t-BHP. Based on the results described above, it is suggested that PLE has the potential to protect liver against t-BHP-induced hepatic damage in rats.     

Direct toxicity of Rose Bengal in MCF-7 cell line: Role of apoptosis

Current therapies for breast cancer are often limited by short-term efficacy due to the emergence of drug resistance. In view of this, there is much interest in the identification of new agents for the treatment of breast cancer. Rose Bengal (RB) has been used as a photosensitiser in photodynamic treatment. In the present study, we investigated the direct cytotoxic and proapoptotic effects of RB, not as a photosensitiser, in MCF-7 cells. Cell viability was quantitated by MTT assay. Apoptotic cells were determined using PI staining of DNA fragmentation by flow cytometry. Bax protein expression was studied by western blotting. ROS was measured using DCF-DA by flow cytometry analysis. The result showed RB decreased cell viability in MCF-7 cells in a concentration- and time-dependent manner. RB induced a sub-G1 peak in flow cytometry histogram of treated cells indicating apoptosis is involved in this toxicity. In Western blot analysis, Bax expression significantly increased in RB-treated cells. RB could also increase ROS production in MCF-7 cells but antioxidant GSH could not decrease the toxicity indicating this toxicity was independent of ROS production. Thus RB exerts proapoptotic effects in a MCF-7 cells and could be considered as a potential chemotherapeutic agent in breast cancer.     

Iron supplementation at high altitudes induces inflammation and oxidative injury to lung tissues in rats

Exposure to high altitudes is associated with hypoxia and increased vulnerability to oxidative stress. Polycythemia (increased number of circulating erythrocytes) develops to compensate the high altitude associated hypoxia. Iron supplementation is, thus, recommended to meet the demand for the physiological polycythemia. Iron is a major player in redox reactions and may exacerbate the high altitudes-associated oxidative stress. The aim of this study was to explore the potential iron-induced oxidative lung tissue injury in rats at high altitudes (6000 ft above the sea level). Iron supplementation (2 mg elemental iron/kg, once daily for 15 days) induced histopathological changes to lung tissues that include severe congestion, dilatation of the blood vessels, emphysema in the air alveoli, and peribronchial inflammatory cell infiltration. The levels of pro-inflammatory cytokines (IL-1β, IL-6, and TNF-α), lipid peroxidation product and protein carbonyl content in lung tissues were significantly elevated. Moreover, the levels of reduced glutathione and total antioxidant capacity were significantly reduced. Co-administration of trolox, a water soluble vitamin E analog (25 mg/kg, once daily for the last 7 days of iron supplementation), alleviated the lung histological impairments, significantly decreased the pro-inflammatory cytokines, and restored the oxidative stress markers. Together, our findings indicate that iron supplementation at high altitudes induces lung tissue injury in rats. This injury could be mediated through excessive production of reactive oxygen species and induction of inflammatory responses. The study highlights the tissue injury induced by iron supplementation at high altitudes and suggests the co-administration of antioxidants such as trolox as protective measures.     

DNA damage in organs of mice treated acutely with patulin, a known mycotoxin

Patulin, a known mycotoxin, is considered a significant contaminant in apples, apple-derived products and feeds. This study investigated the genotoxic effects of patulin in multiple organs (brain, kidney, liver and urinary bladder) of mice using an in vivo comet assay. We assessed the mechanism underlying this genotoxicity by measuring the GSH content and the thiobarbituric acid-reactive species (TBARS) level. Male CF-1 mice were given 1.0-3.75mg/kg patulin intraperitoneally. The effect of patulin was dose-dependent and the highest patulin dose induced DNA strand breaks in the brain (damage index, DI, in hippocampus increased from 36.2 in control animals to 127.5), liver (44.3-138.4) and kidneys (31.5-99); decreased levels of GSH (hippocampus - from 46.9 to 18.4nmol/mg protein); and an increase in lipid peroxidation (hippocampus - from 5.8 to 20.3 MDA equivalents/mg protein). This finding establishes an interrelationship between the pro-oxidant and genotoxic effects of patulin. Pre-treatment administration of N-acetyl-cysteine reduced patulin-induced DNA damage (hippocampus - DI from 127.5 to 39.8) and lipid peroxidation (hippocampus - 20.3 to 12.8 MDA equivalents/mg protein) by restoring cellular GSH levels, reinforcing the positive relationship between patulin-induced GSH depletion and DNA damage caused by systemic administration of this mycotoxin.     

Species-specific toxicity of troglitazone on rats and human by gel entrapped hepatocytes

Troglitazone, despite passing preclinical trials on animals, was shortly withdrawn from market due to its severe hepatotoxicity in clinic. As rat hepatocyte monolayer consistently showed sensitive troglitazone toxicity as human hepatocyte monolayer in contrast to the species-specific toxicity in vivo, this paper utilized both hepatocytes in three-dimensional culture of gel entrapment to reflect the species difference on hepatotoxicity. Rat hepatocytes in gel entrapment did not show obvious cellular damage even under a long-term exposure for 21 days while gel entrapped human hepatocytes significantly displayed oxidative stress, steatosis, mitochondrial damage and cell death at a short exposure for 4 days. As a result, the detected species-specific toxicity of troglitazone between gel entrapped rat and human hepatocytes consisted well with the situation in vivo but was in a sharp contrast to the performance of two hepatocytes by monolayer culture. Such contradictory toxicity of rat hepatocytes between monolayer and gel entrapment culture could be explained by the fact that troglitazone was cleared more rapidly in gel entrapment than in monolayer culture. Similarly, the differential clearance of troglitazone in rat and human might also explain its species-specific toxicity. Therefore, gel entrapment of hepatocytes might serve as a platform for evaluation of drug toxicity at early stage of drug development by reducing costs, increasing the likelihood of clinical success and limiting human exposure to unsafe drugs.     

Elevated glutathione level does not protect against chronic alcohol mediated apoptosis in recombinant human hepatoma cell line VL-17A over-expressing alcohol metabolizing enzymes - Alcohol dehydrogenase and Cytochrome P450 2E1

Chronic consumption of alcohol leads to liver injury. Ethanol-inducible Cytochrome P450 2E1 (CYP2E1) plays a critical role in alcohol mediated oxidative stress due to its ability to metabolize ethanol. In the present study, using the recombinant human hepatoma cell line VL-17A that over-expresses the alcohol metabolizing enzymes - alcohol dehydrogenase (ADH) and CYP2E1; and control HepG2 cells, the mechanism and mode of cell death due to chronic ethanol exposure were studied. Untreated VL-17A cells exhibited apoptosis and oxidative stress when compared with untreated HepG2 cells. Chronic alcohol exposure, i.e., 100 mM ethanol treatment for 72 h caused a significant decrease in viability (47%) in VL-17A cells but not in HepG2 cells. Chronic ethanol mediated cell death in VL-17A cells was predominantly apoptotic, with increased oxidative stress as the underlying mechanism. Chronic ethanol exposure of VL-17A cells resulted in 1.1- to 2.5-fold increased levels of ADH and CYP2E1. Interestingly, the level of the antioxidant GSH was found to be 3-fold upregulated in VL-17A cells treated with ethanol, which may be a metabolic adaptation to the persistent and over-whelming oxidative stress. In conclusion, the increased GSH level may not be sufficient enough to protect VL-17A cells from chronic alcohol mediated oxidative stress and resultant apoptosis.     

Ameliorative role of conjugated linolenic acid isomers against oxidative DNA damage induced by sodium arsenite in rat model

The present study was undertaken to evaluate the ameliorative role of α-eleostearic acid and punicic acid, isomers of conjugated linolenic (CLnA) acid, against oxidative stress induced DNA damage. Male albino rats were divided into six groups. Group 1 and 2 were normal control and sodium arsenite treated (Sa; 10 mg/kg BW) control respectively. Group 3–6 were orally treated with different doses of two fatty acids (0.5% and 1.0% of total lipid given for each isomer) along with sodium arsenite (Sa; 10 mg/kg BW). Comet assay of blood leukocytes showed that administration of CLnA reduced DNA damage significantly (P < 0.05) which was determined by tail DNA percent and olive tail moment. Results showed that activity of antioxidant enzymes viz. catalase, superoxide dismutase (SOD), glutathione peroxidase (GPx) and reduced glutathione (GSH) in plasma, liver and erythrocyte lysate decreased and activity of nitric oxide synthase in plasma and liver increased significantly due to oxidative stress generated by sodium arsenite. Administration of CLnA isomers restored all the altered parameters and also reduced lipid peroxidation and leakage of transaminase enzymes from liver to blood due to liver injury. α-Eleostearic acid was more efficient antioxidant than punicic acid against oxidative DNA damage.     

Lupeol protects against acetaminophen-induced oxidative stress and cell death in rat primary hepatocytes

Drug induced hepatotoxicity is a major problem where phytochemicals hold promise for its abrogation. This study was carried out to explore cytoprotective potential of lupeol, a triterpene, against acetaminophen (AAP)-induced toxicity in rat hepatocytes. AAP exposure significantly (p < 0.05) reduced cell viability, disturbed Bcl-2 family pro/anti-apoptotic protein balance, increased ROS production and altered redox homeostasis. It also induced mitochondria-mediated hepatocellular injury by significant mitochondrial depolarization, caspase-9/3 activation and subsequent DNA fragmentation. Our results suggest that lupeol pre-treatment effectively restored antioxidant enzyme levels, decreased lipid peroxidation, inhibited ROS generation and depolarization of mitochondria. Lupeol also attenuated mitochondria-mediated signaling pathway and DNA damage as evident from TUNEL assay and cell cycle studies leading to prevention of cytotoxicity. This study confirms the efficacy of lupeol, a food derived antioxidant, in abrogating ROS generation, maintaining redox balance and providing significant protection against mitochondria-mediated cell death during AAP-induced toxicity.     

Inhibition of bleomycin-induced cell death in rat alveolar macrophages and human lung epithelial cells by ambroxol

The mitochondrial permeability transition is recognized to be involved in toxic and oxidative forms of cell injury. In the present study, we investigated the effect of ambroxol against the cytotoxicity of bleomycin (BLM) by looking at the effect on the mitochondrial membrane permeability in alveolar macrophages and lung epithelial cells. Alveolar macrophages or lung epithelial cells exposed to BLM revealed the loss of cell viability and increase in caspase-3 activity. Ambroxol (10-100 microM) reduced the 75 mU/mL BLM-induced cell death and activation of caspase-3 in macrophages or epithelial cells. It reduced the condensation and fragmentation of nuclei caused by BLM in macrophages. Ambroxol alone did not significantly cause cell death. Treatment of alveolar macrophages with BLM resulted in the decrease in transmembrane potential in mitochondria, cytosolic accumulation of cytochrome c, increase in formation of reactive oxygen species (ROS) and depletion of GSH. Ambroxol (10-100 microM) inhibited the increase in mitochondrial membrane permeability, ROS formation and decrease in GSH contents due to BLM in macrophages. Ambroxol exerted a scavenging effect on hydroxyl radicals and nitric oxide and reduced the iron-mediated formation of malondialdehyde and carbonyls in liver mitochondria. It prevented cell death due to SIN-1 in lung epithelial cells. The results demonstrate that ambroxol attenuates the BLM-induced viability loss in alveolar macrophages or lung epithelial cells. This effect may be due to inhibition of mitochondrial damage and due to the scavenging action on free radicals.     

Naringin alleviates cognitive impairment,mitochondrial dysfunction and oxidative stress induced by d-galactose in mice

Role of mitochondrial dysfunction and oxidative stress has been well documented in aging and related disorders such as Alzheimer’s disease. Bioflavonoids have been reported to have a therapeutic potential against several age related processes. Bioflavonoids are being used as a neuroprotectants in the treatment of various neurological disorders including aging. Therefore, present study has been conducted in order to explore the possible role of naringin against d-galactose induced cognitive dysfunction, oxidative damage and mitochondrial dysfunction in mice. Chronic administration of d-galactose (100 mg/kg) for 6 weeks significantly impaired cognitive performance (both in Morris water maze and elevated plus maze), locomotor activity, oxidative defense and mitochondrial complex (I, II and III) enzymes activities as compared to sham group. Six weeks naringin (40 and 80 mg/kg) treatment significantly improved cognitive performance, oxidative defense and restored mitochondria complex enzyme activities as compared to control (d-galactose). Naringin treatment significantly attenuated acetylcholine esterase activity in d-galactose treated mice. In conclusion, present study highlights the potential role of naringin against d-galactose induced cognitive impairment, biochemical and mitochondrial dysfunction in mice.     

Suppression of oxidative stress and pro-inflammatory mediators by Cymbopogon citratus D. Stapf extract in lipopolysaccharide stimulated murine alveolar macrophages

Exploration of antioxidants of plant origin and their scientific validation for their immense pharmacological potential is emerging as an issue of intense research now-a-days.The effect of Cymbopogon citratus extract was seen on cell viability, oxidative stress markers i.e. ROS production, SOD activity, lipid peroxidation and GSH content of murine alveolar macrophages stressed with lipopolysaccharide. Modulation in release of NO and pro-inflammatory cytokine TNF-α along with alterations in mitochondrial membrane potential under stress were compared with known plant derived antioxidant quercetin. The extract was not found to be cytotoxic at any of the selected doses. At 5 and 10 μg the extract showed significant increase in SOD activity, GSH content (p < 0.001), decrease in ROS production as seen by fluorescent dye DCFH-DA and also MDA formation (lipid peroxidation marker) significantly. The extract also showed reduction in the release of pro-inflammatory mediators TNF-α and NO significantly indicating an anti-inflammatory effect. The extract was able to restore mitochondrial membrane potential as estimated by spectrofluorimetry using the fluorescent dye Rhodamine 123. The results suggest potential use of the cytoprotective, antioxidant and anti-inflammatory property of C. citratus in the form of dietary component and also in formulations against lung inflammatory diseases where oxidative stress plays an important role.     

Evaluation of cytotoxicity and oxidative DNA damaging effects of di(2-ethylhexyl)-phthalate (DEHP) and mono(2-ethylhexyl)-phthalate (MEHP) on MA-10 Leydig cells and protection by selenium

Di(2-ethylhexyl)-phthalate (DEHP) is the most abundantly used phthalate derivative, inevitable environmental exposure of which is suspected to contribute to the increasing incidence of testicular dysgenesis syndrome in humans. Oxidative stress and mitochondrial dysfunction in germ cells are suggested to contribute to phthalate-induced disruption of spermatogenesis in rodents, and Leydig cells are one of the main targets of phthalates’ testicular toxicity. Selenium is known to be involved in the modulation of intracellular redox equilibrium, and plays a critical role in testis, sperm, and reproduction. This study was aimed to investigate the oxidative stress potential of DEHP and its consequences in testicular cells, and examine the possible protective effects of selenium using the MA-10 mouse Leydig tumor cell line as a model. In the presence and absence of selenium compounds [30 nM sodium selenite (SS), and 10 μM selenomethionine (SM)], the effects of exposure to DEHP and its main metabolite mono(2-ethylhexyl)-phthalate (MEHP) on the cell viability, enzymatic and non-enzymatic antioxidant status, ROS production, p53 expression, and DNA damage by alkaline Comet assay were investigated. The overall results of this study demonstrated the cytotoxicity and genotoxicity potential of DEHP, where MEHP was found to be more potent than the parent compound. SS and SM produced almost the same level of protection against antioxidant status modifying effects, ROS and p53 inducing potentials, and DNA damaging effects of the two phthalate derivatives. It was thus shown that DEHP produced oxidative stress in MA-10 cells, and selenium supplementation appeared to be an effective redox regulator in the experimental conditions used in this study, emphasizing the critical importance of the appropriate selenium status.     

The neuroprotective action of pyrroloquinoline quinone against glutamate-induced apoptosis in hippocampal neurons is mediated through the activation of PI3K/Akt pathway

Pyrroloquinoline quinone (PQQ), a cofactor in several enzyme-catalyzed redox reactions, possesses a potential capability of scavenging reactive oxygen species (ROS) and inhibiting cell apoptosis. In this study, we investigated the effects of PQQ on glutamate-induced cell death in primary cultured hippocampal neurons and the possible underlying mechanisms. We found that glutamate-induced apoptosis in cultured hippocampal neurons was significantly attenuated by the ensuing PQQ treatment, which also inhibited the glutamate-induced increase in Ca2+ influx, caspase-3 activity, and ROS production, and reversed the glutamate-induced decrease in Bcl-2/Bax ratio. The examination of signaling pathways revealed that PQQ treatment activated the phosphorylation of Akt and suppressed the glutamate-induced phosphorylation of c-Jun N-terminal protein kinase (JNK). And inhibition of phosphatidylinositol-3-kinase (PI3K)/Akt cascade by LY294002 and wortmannin significantly blocked the protective effects of PQQ, and alleviated the increase in Bcl-2/Bax ratio. Taken together, our results indicated that PQQ could protect primary cultured hippocampal neurons against glutamate-induced cell damage by scavenging ROS, reducing Ca2+ influx, and caspase-3 activity, and suggested that PQQ-activated PI3K/Akt signaling might be responsible for its neuroprotective action through modulation of glutamate-induced imbalance between Bcl-2 and Bax.     

Methiocarb-induced oxidative damage following subacute exposure and the protective effects of vitamin E and taurine in rats

Methiocarb, is used worldwide in agriculture and health programs. Besides its advantages in the agriculture, it causes several toxic effects. In this study, we aimed to investigate subacute effects of methiocarb on lipid peroxidation, reduced glutathione (GSH), antioxidant enzymes such as superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GSH-Px) and glutathione reductase (GSH-Rd) and histopathological changes in rat tissues. Moreover, we examined the possible protective effects of vitamin E and taurine on methiocarb-induced oxidative damage in rat tissues. Rats were randomly divided into six groups as follows; I-control group; II-methiocarb group; III-vitamin E group; IV-vitamin E + methiocarb group; V-taurine group and VI-taurine + methiocarb group. Methiocarb significantly increased lipid peroxidation in liver and kidney when compared to control groups. Levels of GSH and activities of SOD, CAT and GSH-Px were found to be decreased, while GSH-Rd remained unchanged in rat liver and kidney treated with methiocarb. Pretreatment of vitamin E and taurine resulted in a significant decrease on lipid peroxidation, alleviating effects on GSH and antioxidant enzymes. The degenerative histological changes were less in liver than kidney of rats treated with methiocarb. Pretreatment of vitamin E and taurine showed a protective effect on the histological changes in kidney comparing to the liver of rats treated with methiocarb.     

Hepatotoxicity of tubers of Indian Kudzu (Pueraria tuberosa) in rats

Methanolic extract of tubers of Pueraria tuberosa Linn. (Fabaceae) (PTME) has been tested for hepatoxicity in rats. In acute study, PTME (100–400 mg/100 g BW, given orally) showed LD₅₀ at 227.5 mg. For sub-chronic study, its repeated doses (5–100 mg/100 g BW, for 30 days), significantly increased hepatic enzymes in blood, sinusoidal congestion, disruption of central vein, inflammatory cell infiltration and hepatocellular necrosis in liver in dose dependent manner, with increase in NO, iNOS and ROS levels. In a kinetic study (single dose 227.5 mg/100 g BW), there was sequential decrease in GSH and enhanced NO suggesting free-radical generation as the primary cause of cell damage. It is concluded that the higher dosing of PTME or its continuous use for longer period (even in low doses) is hepatotoxicity by inducing oxidative stress.     

Antioxidative function and biodistribution of [Gd@C82(OH)22]n nanoparticles in tumor-bearing mice

Oxidative stress is considered to be one of the important mechanisms involved in carcinogenesis. In our previous study, gadolinium endohedral metallofullerenol ([Gd@C82(OH)22]n nanoparticles) have shown high inhibitory activity on hepatoma cell (H22) growth in mice. To explore the antioxidative functions of nanoparticles, we investigated the biodistribution of [Gd@C82(OH)22]n nanoparticles, the changes of blood coagulation profiles, the metabolism of reactive oxygen species (ROS) in the tumor-bearing mice as well as the possible relationships between nanoparticles treatment and ROS production in this paper. The activities of hepatic superoxide dismutase (SOD), glutathione peroxidase (GSH-Px), glutathione S-transferase (GST) and catalase (CAT) as well as the levels of reduced glutathione (GSH), protein-bound thiols and malondialdehyde (MDA) were compared between the tumor-bearing mice and normal mice. Transplanted tumors were grown in mice by subcutaneous injection of murine hepatoma cells in the mice. The comparison of the above parameters between nanoparticles and cyclophosphamide (CTX) therapy were also investigated. [Gd@C82(OH)22]n administration can efficiently restore the damaged liver and kidney of the tumor-bearing mice. All the activities of enzymes and other parameters related to oxidative stress were reduced after [Gd@C82(OH)22]n treatment and tended closely to the normal levels. The results suggest that [Gd@C82(OH)22]n nanoparticle treatment could regulate ROS production in vivo.