Carbon Tetrachloride Hepatotoxicity Research Articles

Hepatoprotective effect of Mahonia oiwakensis stems against carbon tetrachloride hepatotoxicity

This study using in vitro and in vivo models investigates hepatoprotective activities of the ethanol extract of Mahonia oiwakensis stems (MOSEtOH). Anti-oxidative activity of MOSEtOH was evaluated by 2, 2-diphenlyl-1-picrylhydrazyl (DPPH) radical. Wistar rats were orally pretreated with MOSEtOH (20, 100 and 500mg/kg) and silymarin (200mg/kg) for three consecutive days with administration of carbon tetrachloride (CCl4) (1ml/kg, 50% CCl4 in olive oil). The results showed that MOSEtOH exhibited anti-oxidative activity in the DPPH (IC50, 0.743mg/mL) assay. Treatment with MOSEtOH (100 and 500mg/kg) or silymarin decreased the AST and ALT levels in serum when compared with CCl4-treated group. Histological analyses also show that MOSEtOH and silymarin reduced the incidence of liver lesions including vacuole formation, neutrophil infiltration and necrosis of hepatocytes induced by CCl4 in rats. Additionally, MOSEtOH and silymarin attenuated the decreased protein activities of superoxide dismutase (SOD), glutathione peroxidase (GPx) and glutathione reductase (GRd) and increased malondialdehyde (MDA) and nitric oxide (NO) contents in liver as compared with CCl4-treated group. In conclusion, the MOSEtOH (100 and 500mg/kg) has a strong hepatoprotective effect on CCl4-induced hepatic injury in rats and can be used as pharmacological agent for the prevention of liver disorders.

Long-Term Treatment with Shengmai San-Derived Herbal Supplement (Wei Kang Su) Enhances Antioxidant Response in Various Tissues of Rats with Protection Against Carbon Tetrachloride Hepatotoxicity

Wei Kang Su (WKS) is a commercial herbal product based on a Chinese herbal formula, Shengmai San. Here, we investigated the effects of long-term treatment with WKS on mitochondrial antioxidant status and functional ability, as well as heat shock protein (Hsp) 25/70 production, in various tissues of rats. WKS treatment enhanced mitochondrial antioxidant status and ATP generation capacity, as well as Hsp 25/70 production in various rat tissues. WKS treatment suppressed plasma reactive oxygen metabolite levels and protected against carbon tetrachloride hepatotoxicity in rats. Long-term WKS treatment may prevent diseases by enhancing the resistance of mitochondria to oxidative stress.

Insulin resistance induced by high-fructose diet potentiates carbon tetrachloride hepatotoxicity

Insulin resistance (IR) is recognized as a contributory factor for a variety of liver diseases. The present study investigates the susceptibility of liver to the toxic actions of carbon tetrachloride (CCl(4)) in a rat model of IR, induced by feeding a high-fructose diet (60 g/100 g) for 30 days. A sub-lethal dose of CCl(4) (2 mL/kg intraperitoneally [i.p.], in corn oil) was administered and the outcome of hepatotoxicity was assessed at 0 hour and at 6, 12, 24 and 36 hours after CCl(4) administration. After 30 days of fructose feeding, the rats showed IR, decline in liver antioxidant status and rise in lipid peroxidation. Liver dysfunction in fructose-fed rats was evident from a rise in transaminases, total bilirubin and a decrease in albumin/globulin ratio in plasma and decreases in nitrite, arginase and increase in protein carbonyl and nitrosothiol content in liver. Increased staining for 3-nitro tyrosine (3-NT) antibody was observed in fructose-fed rat liver as compared to control. CCl(4) (2 mL/kg) caused 100% mortality in fructose-fed rats within 48 hours, while no death of animals occurred in control. CCl(4) caused liver damage in both control and fructose-fed rats. Time-based studies showed that progressive liver injury occurred only in fructose-fed rats from 0, 6, 12, 24 hours, with a peak at 36 hours. In control diet-fed rats, the extent of damage was maximum at 24 hours, which declined at 36 hours. Thus, the toxic effects of CCl(4) are potentiated due to compromised liver function in the setting of IR.

Exposure to Oscillating High Electrical Potential and the Associated Low Frequency Magnetic Field Enhances the Hepatoprotective Action of Schisandrin B in Vivo and in Vitro

The effect of electromagnetic manipulation (EM), consisting of an oscillating (50 Hz) high electrical potential (a maximum value of 20,000 V and an output current < 100 µA) and its associated alternating magnetic field (50-60 Guass), on the hepatoprotective action of schisandrin B (Sch B, an active ingredient isolated from the fruit of Schisandra chinensis) was examined in the mouse model of carbon tetrachloride (CCl4) hepatotoxicity and the AML12 cell model of menadione-induced toxicity. EM was found to enhance the Sch B-induced hepatoprotective action against CCl4 toxicity in mice and cytoprotective action against menadione toxicity in AML12 hepatocytes. The potentiating effect of EM on the pharmacological action of Sch B may be mediated by the increase in drug availability to tissues or cells and/or the pro-oxidant action of electromagnetic field in vivo.

Carbon tetrachloride-induced liver damage in asialoglycoprotein receptor-deficient mice

The asialoglycoprotein (ASGP) receptor is an abundant hepatocyte-specific receptor involved in receptor-mediated endocytosis. This receptor's abundance and function is decreased by chronic ethanol administration prior to the appearance of pathology such as necrosis or inflammation. Hence, this study aimed to determine if ASGP receptor function is required to protect against liver injury by utilizing a knockout mouse model lacking functional ASGP receptor in the setting of carbon tetrachloride (CCl 4) hepatotoxicity. Briefly, ASGP receptor-deficient (RD) mice and wild-type (WT) mice were injected with 1 ml/kg body weight of CCl 4. In the subsequent week, mice were monitored for liver damage and pathology (aspartate transaminase (AST), alanine transaminase (ALT) and light microscopy). The consequences of CCl 4 injection were examined by measuring α-smooth muscle actin (α-SMA) deposition, contents of malondialdehyde and the percentage of apoptotic hepatocytes. After CCl 4 injection, RD mice showed increased liver pathology together with significantly increased activities of AST and ALT compared to that in WT mice. There were also significantly more apoptotic bodies, lipid peroxidation and deposition of α-SMA in RD mice versus WT mice following CCl 4 injection. Since these two mouse strains only differ in whether or not they have the ASGP receptor, it can be concluded that proper ASGP receptor function exerted a protective effect against CCl 4 toxicity. Thus, receptor-mediated endocytosis by the ASGP receptor could represent a novel molecular mechanism that is responsible for subsequent liver health or injury.

Protection of Regenerating Liver After Partial Hepatectomy from Carbon Tetrachloride Hepatotoxicity in Rats: Roles of Mitochondrial Uncoupling Protein 2 and ATP Stores

Uncoupling protein 2 (UCP(2)), an inner mitochondrial membrane protein, can limit the generation of reactive oxygen species (ROS) and protect cells from injuries mediated by oxidative stress. We investigated the effect of upregulation of UCP(2) in the regenerating liver 96 h after 68% partial hepatectomy (PH) on the self-protection of regenerating liver against carbon tetrachloride (CCl(4)) poisoning. Hepatotoxicity was induced in vivo by administering CCl(4) to rats that had undergone PH. After CCl(4) poisoning, the regenerating liver appeared to have less histological damage and lower serum alanine aminotransferase (ALT) levels. Lower malondialdehyde production and higher glutathione contents were also observed in the regenerating liver compared with the sham-operated liver after CCl(4) poisoning. UCP(2) expression was markedly elevated in the regenerating liver, and further increased after CCl(4) intoxication. Mitochondrial membrane potential and adenosine triphosphate stores maintained higher levels in the regenerating liver than in sham-operated liver after CCl(4) intoxication. The results showed that the regenerating liver exhibited a potent ability to resist CCl(4) intoxication, and the autoprotection of regenerating liver might result from reduction of ROS by UCP(2) and maintenance of higher ATP stores.

Is Serum Gamma-Glutamyltransferase a Biomarker of Xenobiotics, Which Are Conjugated by Glutathione?

A meta-analysis of 10 prospective cohort studies,1 including our own,2 reported that serum γ-glutamyltransferase (GGT) predicted incident vascular events. This meta-analysis posed one important, but unsolved question: why does serum GGT predict incident vascular events? In addition to vascular events, serum GGT predicts various important clinical outcomes including type 2 diabetes, metabolic syndrome, and renal problems.3–5 Serum GGT has traditionally been used as a marker of alcohol consumption; however, alcohol consumption cannot explain the disease relationships with serum GGT because these associations have been observed among nondrinkers as well as drinkers. The other prevailing interpretations are that serum GGT predicts clinical outcomes as a marker of nonalcoholic fatty liver disease (NAFLD) or oxidative stress.6–8 Although both of these explanations have some merit, each also has problems. Although not clearly stated in many of the reports,1–5 most associations of serum GGT with clinical outcomes were dose-response relations within the normal range of serum GGT; we submit that this aspect of the association is critical to interpretation. First, even though NAFLD may partially explain the associations among subjects with a relatively high serum GGT activity and NAFLD can present even among subjects with low normal serum GGT, NAFLD is unlikely to fully explain the graded associations with clinical outcomes which were observed among subjects with serum GGT in the low part of its normal range, less than 20 or 30 U/L. However, it is worthwhile to note that serum GGT may be a predictor of the future risk of NAFLD. In a prospective study by our group,9 serum GGT within its normal range strongly predicted the future risk of chronic elevation of serum alanine aminotransferase (ALT), but serum ALT within its normal range did not predict the future risk of chronic elevation of serum GGT. The …

Hepatocyte-Specific Deletion of Heme Oxygenase-1 Disrupts Redox Homeostasis in Basal and Oxidative Environments

Heme oxygenase-1 (HO-1) is the rate-limiting enzyme of heme catabolism and has been assumed to be important in cellular response against oxidative stress through modification of the pro-oxidant heme into less toxic catabolites that behave as antioxidants. However, the precise mechanisms involved and the physiological significance of such activity remain to be clarified. To elucidate roles HO-1 plays in vivo, hepatocyte-specific conditional knockout (CKO) mice of HO-1 gene were generated by site-specific recombination using albumin-promoter-driven Cre-loxP system. In livers of HO-1 CKO mice HO-1 protein level decreased to approximately 30% of control mouse livers. The HO-1 CKO mice are viable, exhibit normal growth curves over six months, and show no histological and serological abnormalities. We found that several cytoprotective genes, such as NAD(P)H dehydrogenase quinone 1 and glutathione S-transferase P1, showed markedly elevated expression, suggesting the increase of oxidative stress in HO-1 CKO mice even under quiescent conditions. In vivo electron paramagnetic resonance studies demonstrated that signal decay times of nitroxyl radicals were significantly longer in livers of HO-1 CKO mice than that of control mice, indicating that radical scavenging activity was significantly compromised in the mutant liver. HO-1 CKO mice were susceptible to carbon tetrachloride hepatotoxicity. These results provide the first in vivo evidence that HO-1 acts to protect cells against the oxidative stress in both basal conditions and upon chemical insult.

Protective effects of N‐acetyl‐L‐cysteine against acute carbon tetrachloride hepatotoxicity in rats

In recent years, N-acetyl-L-cysteine (NAC) has been widely investigated as a potentially useful protective and antioxidative agent to be applied in many pathological states. The aim of the present work was further evaluation of the mechanisms of the NAC protective effect under carbon tetrachloride-induced acute liver injuries in rats. The rat treatment with CCl4 (4 g/kg, intragastrically) caused pronounced hepatolysis observed as an increase in blood plasma bilirubin levels and hepatic enzyme activities, which agreed with numerous previous observations. The rat intoxication was accompanied by an enhancement of membrane lipid peroxidation (1.4-fold) and protein oxidative damage (protein carbonyl group and mixed protein-glutathione disulphide formations) in the rat liver. The levels of nitric oxide in blood plasma and liver tissue significantly increased (5.3- and 1.5-fold, respectively) as blood plasma triacylglycerols decreased (1.6-fold). The NAC administration to control and intoxicated animals (three times at doses of 150 mg/kg) elevated low-molecular-weight thiols in the liver. The NAC administration under CCl4-induced intoxication prevented oxidative damage of liver cells, decreased membrane lipid peroxidation, protein carbonyls and mixed protein-glutathione disulphides formation, and partially normalized plasma triacylglycerols. At the same time the NAC treatment of intoxicated animals did not produce a marked decrease of the elevated levels of blood plasma ALT and AST activities and bilirubin. The in vitro exposure of human red blood cells to NAC increased the cellular low-molecular-weight thiol levels and retarded tert-butylhydroperoxide-induced cellular thiol depletion and membrane lipid peroxidation as well as effectively inhibited hypochlorous acid-induced erythrocyte lysis. Thus, NAC can replenish non-protein cellular thiols and protect membrane lipids and proteins due to its direct radical-scavenging properties, but it did not attenuate hepatotoxicity in the acute rat CCl4-intoxication model.

Schisandrin B Decreases the Sensitivity of Mitochondria to Calcium Ion-Induced Permeability Transition and Protects against Carbon Tetrachloride Toxicity in Mouse Livers

Schisandrin B (Sch B), a dibenzocyclooctadiene derivative isolated from the fruit of Schisandra chinensis, has been shown to protect against carbon tetrachloride (CCl4) hepatotoxicity in mice. In order to elucidate the molecular mechanism underlying the hepatoprotection afforded by Sch B, the effect of Sch B treatment on the sensitivity of mitochondria to Ca2+-stimulated permeability transition (PT) was investigated in mouse livers under normal and CCl4-intoxicated conditions. CCl4 hepatotoxicity caused an increase in the sensitivity of mitochondria to Ca2+-stimulated PT in vitro. The enhanced sensitivity to mitochondrial PT was associated with increases in mitochondrial Ca2+ content as well as the extent of reactive oxidant species (ROS) production and cytochrome c release. The hepatoprotection afforded by Sch B pretreatment against CCl4 toxicity was paralleled by the decrease in the sensitivity of hepatic mitochondria to Ca2+-stimulated PT as well as the attenuations of mitochondrial Ca2+ loading, ROS production and cytochrome c release under CCl4-intoxicated condition. In conclusion, the results suggest that the hepatoprotection afforded by Sch B pretreatment against CCl4 toxicity may be related to the increase in the resistance of hepatic mitochondria to Ca2+-stimulated PT.

One-Day Dietary Restriction Changes Hepatic Metabolism and Potentiates the Hepatotoxicity of Carbon Tetrachloride and Chloroform in Rats

Although dietary restriction (DR) is common in modern society, research about hepatic metabolism and the hepatotoxicity induced by DR has been conducted less intensively than that induced by fasting. In the present study, we fed male Wistar rats at five levels of food intake for one day, including conventional feeding (60 kcal), three of DR (45, 30, and 15 kcal), and fasting (0 kcal), and observed the metabolic changes of hepatic cytochrome P450 2E1(CYP2E1) and the hepatotoxicity of chloroform (CHCl(3)) and carbon tetrachloride (CCl(4)). The CYP2E1 content was significantly increased in 15 kcal-food and fasting groups. The hepatic glutathione (GSH) content, which protects the liver from hepatotoxic agents, was depleted in 15 kcal-food and fasting groups. After the challenge by CHCl(3) and CCl(4), the activities of aspartate aminotransferase and alanine aminotransferase, marker enzymes for liver damage, were elevated remarkably at all food groups. Moreover, their activities increased significantly in DR groups, in comparison to the corresponding 60 kcal-food group. After the challenge, the hepatic GSH content was also depleted significantly in 15 kcal-food and fasting groups. CHCl(3) was cleared by hepatic metabolism about 8-10 times faster than that of CCl(4). Similarly, the areas under the blood concentration-time curve of CCl(4) was as much as twice that of the corresponding CHCl(3). In conclusion, when food was restricted to less than half of conventional amount, hepatic metabolism was affected and the hepatotoxicity induced by CCl(4) or CHCl(3) was augmented by, at least in part, CYP2E1 induction and GSH depletion.

Nonalcoholic fatty liver sensitizes rats to carbon tetrachloride hepatotoxicity

This study tested whether hepatic steatosis sensitizes liver to toxicant-induced injury and investigated the potential mechanisms of hepatotoxic sensitivity. Male Sprague-Dawley rats were fed a methionine- and choline-deficient diet for 31 days to induce steatosis. On the 32nd day, administration of a nonlethal dose of CCl4 (2 mL/kg, intraperitoneally) yielded 70% mortality in steatotic rats 12-72 hours after CCl4 administration, whereas all nonsteatotic rats survived. Neither CYP2E1 levels nor covalent binding of [14C] CCl4-derived radio-label differed between the groups, suggesting that increased bioactivation is not the mechanism for this amplified toxicity. Cell division and tissue repair, assessed by [3H]thymidine incorporation and proliferative cell nuclear antigen assay, were inhibited in the steatotic livers after CCl4 administration and led to progressive expansion of liver injury culminating in mortality. The hypothesis that fatty hepatocytes undergo cell cycle arrest due to (1) an inability to replenish ATP due to overexpressed uncoupling protein-2 (UCP-2) or (2) induction of growth inhibitor p21 leading to G1/S phase arrest was tested. Steatotic livers showed 10-fold lower ATP levels due to upregulated UCP-2 throughout the time course after CCl4 administration, leading to sustained inhibition of cell division. Western blot analysis revealed an up-regulation of p21 due to overexpression of TGF beta1 and p53 and down-regulation of transcription factor Foxm 1b in steatotic livers leading to lower phosphorylated retinoblastoma protein. Thus, fatty hepatocytes fail to undergo compensatory cell division, rendering the liver susceptible to progression of liver injury. Impaired tissue repair sensitizes the steatotic livers to hepatotoxicity.

Antioxidative and In Vitro hepatoprotective activity of Bupleurum kaoi leaf infusion

The roots of Bupleurus spp. have been used in traditional Chinese herbal medicine for curing liver diseases. Although bioactive saikosaponins have been detected in the leaves as well as in the roots, the aerial parts of the plants are discarded as waste. In the present study, a leaf infusion of B. kaoi Liu, Chao et Chuang, an indigenous Bupleurus species in Taiwan, was prepared and the antioxidant properties and in vitro hepatoprotective activity were demonstrated. The results show that the leaf infusion exerted DPPH free radical scavenging activity, inhibitory capacity on superoxide anion formation and superoxide anion scavenging activity. The hepatotoxicity of acetaminophen (APAP) and carbon tetrachloride (CCl4) on the rat liver cells were also decreased by the leaf infusion.

The course of CCl 4 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 α-class GSTs also provide protection against oxidative stress and lipid peroxidation (LPO). GSTA4-4 is a member of a sub group of the α-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.

Effects of Callophyllis japonica powder on carbon tetrachloride-induced liver injury in rats

A limited number of studies have been conducted on the bioactivity of Callophyllis japonica (C. japonica), which is a red seaweed that is traditional in the oriental diet. In this report, the hepatoprotective effect of C. japonica was studied in a carbon tetrachloride hepatotoxicity model in rats. A single intraperitoneal injection of 1.25 ml/kg of 20% in olive oil produced an elevated level of serum glutamic pyruvic transaminase (SGPT) and increased enzyme activity of serum glutamic oxaloacetic transaminase (SGOT). Pre-treatment with C. japonica (150 mg/kg/d) for 3 days in rats reduced the levels of SGPT and SGOT compared with control levels (P injection in rats was ineffective at reducing SGPT and SGOT. The histopathological findings in each group largely agreed with the biochemical data. The results of this study support the suggestion that C. japonica has a hepatoprotective effect on chemical-induced liver injury.

Cholestasis induced by model organic anions protects from acetaminophen hepatotoxicity in male CD-1 mice

Administration of the non-metabolizable organic anion indocyanine green (ICG) prior to a toxic dose of acetaminophen (4-acetamidophenol; APAP) reduces liver injury 24 h after dosing. ICG also produces a dose-dependent decrease in bile flow in mice and rats. Studies in bile duct-cannulated rats suggest that cholestasis can play a role in this protection. This study was conducted to determine if the ability of model organic anions to produce cholestasis is relevant to the protection against APAP hepatotoxicity afforded by ICG. In these studies, overnight fasted male CD-1 mice were dosed ( i.v.) with the cholestatic dyes bromcresol green (BCG, 30 μmol/kg) and rose bengal (RB, 60 μmol/kg) immediately prior APAP administration (500 mg/kg, i.p.). Other groups of mice received the non-cholestatic dyes dibromosulphthalein (DBSP, 150 μmol/kg) and amaranth (AM, 300 μmol/kg) prior to APAP. Controls were given vehicle only. Hepatocellular necrosis was evident at 24 h in control mice receiving APAP. Pretreatment with the cholestatic dyes BCG and RB decreased the severity of hepatocellular necrosis induced by APAP. However, administration of the non-cholestatic dyes DBSP and AM did not alter APAP-induced liver damage. Glutathione replenishment was not altered by pretreatment with any of these dyes. Furthermore, ICG protected mice against carbon tetrachloride (CCl 4) hepatotoxicity. Since CCl 4 undergoes minimal biliary excretion and does not compete for biliary transport fuction, this finding supports the notion that cholestasis itself rather than competition for canalicular transporters is central to the hepatoprotection by ICG and other cholephilic dyes.

Voglibose potentiates the hepatotoxicity of carbon tetrachloride and acetaminophen by inducing CYP2E1 in rats

: Voglibose is an alpha-glucosidase inhibitor used to decrease postprandial hyperglycemia in diabetic patients. Although clinical concern has not yet been raised, hepatic dysfunction has been reported in a few patients taking this drug. : In the present study, we studied the effects of voglibose on the hepatotoxicity of carbon tetrachloride (CCl(4)) and acetaminophen (APAP) in rats, since both of these agents exert their effects through isoforms of cytochrome P450. Male Sprague-Dawley rats were given a daily ration (20g) of powdered chow diet containing 0, 2.5, 5.0 or 10.0mg/100g of voglibose. Three weeks later, the rats were challenged with either 0.50g/kg CCl(4) orally or 0.75g/kg APAP intraperitoneally for biochemical examinations or killed for an in vivo metabolism study. : Voglibose at these three experimental doses potentiated CCl(4) and APAP hepatotoxicity, as evidenced by significantly increased levels of both plasma asparate transaminase (AST) and alanine transaminae (ALT). The glutathione (GSH) content was decreased while malondialdehyde (MDA) increased in the liver after CCl(4) or APAP administration. Hepatic cytochrome P450 2E1 (CYP2E1) concentration was increased at doses of 5.0 and 10.0mg/100g of voglibose and its activity increased in the three voglibose dosage groups, while hepatic cytochrome P450 3A (CYP3A) and cytochrome P450 1A2 (CYP1A2) were only slightly changed at any dose. : Our study demonstrated that voglibose can potentiate CCl(4) and APAP hepatotoxicity in rats by inducing hepatic CYP2E1.

Effect of Aerva lanata against hepatotoxicity of carbon tetrachloride in rats

The partially purified petroleum ether extractable fraction of the whole plant Aerva lanata (PF) was evaluated for the protective effect against liver damage induced by carbon tetra chloride (CCl 4) in Sprague Dawley rats. Rats were orally administered with PF (50 and 100 mg/kg body weight) for 14 days before CCl 4 challenge and 100 mg of PF alone for toxicity analysis without CCl 4 administration. The results showed that CCl 4 administration significantly damaged the liver as evident from histopathology and very high activity of serum and liver marker enzymes. It also reduced the antioxidant enzyme status of the animals. PF administration significantly reversed the histopathological changes and restored the elevated activities of liver marker enzymes and also enhanced the antioxidant enzyme activities. The extract also reduced hepatic lipid peroxidation and increased the serum total protein and albumin/globulin (A/G) ratio. Preliminary phytochemical analysis of PF showed the presence of alkaloids. These observations clearly indicate that PF contains antioxidant alkaloids capable of ameliorating the CCl 4-induced hepatic injury by virtue of its antioxidant activity.

Apoptosis initiated by carbon tetrachloride in mitochondria of rat primary cultured hepatocytes

To investigate the mitochondria-initiated apoptosis pathway involved in Carbon tetrachloride (CCl4) hepatotoxicity in vitro. Several cytotoxicity endpoints, including WST-8 metabolism, lactate dehydrogenase leakage and morphological changes, were examined. The 5,5'-dithio-bis(2-nitrobenzoic acid) reaction was used to measure reduced glutathione level, and the malondialdehyde level was determined using the thiobarbituric acid assay. The release of cytochrome c and Bcl-X(L) was detected by Western blot. Caspase-3 activity was measured using the fluorogenic substrate Ac-DEVD-AMC. DNA fragmentation was used to evaluate cell apoptosis. A time- and dose-dependent decrease in cellular glutathione content was observed, along with a concomitant increase in malondialdehyde levels following the application of CCl4. Caspase 3 activity was stimulated at all doses of CCl4, with the most significant activation at 3 mmol/L. Cytochrome c was released obviously after CCl4 treatment. A time-dependent decrease in Bcl-X(L) expression was observed. DNA fragmentation results revealed apoptosis and necrosis following CCl4 treatment. Oxidative damage is one of the essential mechanisms of CCl4 hepatotoxicity, which triggers apoptosis via the mitochondria-initiated pathway.

Amendments to Indian drugs and cosmetics act and rules pertaining to blood banks in armed forces

Cynomorium songaricum, which is an herbal tonic for treating impotence in Chinese medicine, serves as a popular health-promoting or invigorating food in China, particularly in the Inner Mongolia Province. Recent studies have shown that HCY2, an active fraction of C. songaricum, and its major ingredient ursolic acid (UA), protect against myocardial ischemia/reperfusion injury in rats. In the present study, we further investigated the effects of HCY2 or UA on carbon tetrachloride (CCl4) hepatotoxicity and gentamicin nephrotoxicity in rats. The results indicated that HCY2 pretreatment protected against CCl4 hepatotoxicity and gentamicin nephrotoxicity, as evidenced by the significant inhibition of plasma aspartate aminotransferase and alanine aminotransferases activities as well as decreases in plasma creatinine and blood urea nitrogen levels, respectively. The hepatoprotection and nephroprotection were associated with the improvement in mitochondrial functional ability, as assessed by the measurement of ATP generation capacity, as well as the enhancement in glutathione redox status, possibly through the induction of mitochondrial uncoupling in rat liver and kidney tissues. However, UA pretreatment at doses equivalent to those of HCY2 was found to protect against CCl4 hepatotoxicity but not gentamicin nephrotoxicity in rats. The discrepancy between HCY2 and UA may be related to the bioavailability of UA to kidney tissue in rats.