Search

Abstract: This study examined the effects and possible mechanisms of rifampin against acetaminophen-induced hepatotoxicity in mice. Rifampin significantly enhanced the biotransformation of acetaminophen, evidenced by the increase in p-aminophenol formation in rifampin-treated microsomes and the increase in plasma clearance rate of acetaminophen. Pretreatment with rifampin significantly decreased serum alanine transaminase (ALT) activities, aspartate transaminase (AST) activities and prevented severe liver necrosis following acetaminophen overdose. The contents and activities of microsomal drug-metabolizing enzyme were less affected in rifampin-pretreated mice in comparison to the animals treated with acetaminophen alone. Rifampin was capable of increasing glutathione (GSH) level and GSH reductase activity and reducing GSH depletion and the decrease in GSH reductase activity by acetaminophen in mice. In addition, it was found that the microsomal Ca2+-ATPase activity was not directly related to acetaminophen toxic species generated in the P450 enzyme system in vitro. These findings suggest that rifampin has species-specific effects on the liver against acetaminophen-induced hepatotoxicity in mice, which increase the level of GSH by promoting GSH regeneration. [Copyright &y& Elsevier]

Abstract: In this study, rats were orally treated with the total saponins of Taraphochlamys affinis (TSTA) daily with administration of CCl4 twice a week for 8weeks. Compared to the normal control, CCl4 induced liver damage significantly increased the activities of alanine aminotransferase (ALT), aspartate aminotransferase (AST) and alkaline phosphatase (ALP) in serum and decreased the activities of superoxide dismutase (SOD), catalase, glutathione peroxidase (GSH-Px), and glutathione reductase (GSH-Rd) in liver. Meanwhile content of hepatic malondialdehyde (MDA), which was oxidative stress marker, was increased. Histological finding also confirmed the hepatotoxic characterization in rats. Furthermore, proinflammatory mediators including tumor necrosis factor-α(TNF-α) in serum, prostaglandin E2 (PGE2), inducible enitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2) in liver were detected with elevated contents, while expression of xenobiotic metabolizing enzyme – cytochrome P4502E1 (CYP2E1) was inhibited. The results revealed that TSTA not only significantly reversed CCl4 originated changes in serum toxicity and hepatotoxic characterization, but also altered expression of hepatic oxidative stress markers and proinflammatory mediators, combined with restoring liver CYP2E1 level. The results indicated that protective effect of TSTA against CCl4-induced hepatic injury may rely on its effect on reducing oxidative stress, suppressing inflammatory responses and improving drug-metabolizing enzyme activity in liver. [Copyright &y& Elsevier]

Abstract: This study was designed to investigate the protective effects of the methyl helicterate (MH) isolated from Helicteres angustifolia L. against CCl4-induced hepatotoxicities in rats. Liver injury was induced in rats by the administration of CCl4 twice a week for 8weeks. Compared with the CCl4 group, MH significantly decreased the activities of ALT, AST and ALP in the serum and increased the activities of SOD, GSH-Px and GSH-Rd in the liver. Moreover, the content of hepatic MDA was reduced. Histological findings also confirmed the anti-hepatotoxic characterisation. In addition, MH significantly inhibited the proinflammatory mediators, such as PGE2, iNOS, COX-2, IL-6, TNF-α and myeloperoxidase (MPO). Further investigation showed that the inhibitory effect of MH on the proinflammatory cytokines was associated with the downregulation of NF-κB. Besides, MH also markedly decreased the levels of Fas/FasL protein expression and the activities of caspase-3/8, as well as the activity of cytochrome P4502E1 (CYP2E1). In brief, the protective effect of MH against CCl4-induced hepatic injury may rely on its ability to reduce oxidative stress, suppress inflammatory responses, protect against Fas/FasL-mediated apoptosis and block CYP2El-mediated CCl4 bioactivation. [Copyright &y& Elsevier]

Abstract: This study was designed to evaluate the potential effects of puerarin (PR), an effective isoflavonoid compound purified from Pueraria lobata, in treating hepatic fibrosis (HF) rats induced by carbon tetrachloride (CCl4, 2mLkg−1 d−1). Compared to model control, PR treatment effectively lowered the serum levels of alanine aminotransferase (ALT), aspartate aminotransferase (AST), albumin (Alb), total protein (TP) in HF rats. Masson stained analysis showed that the condition of HF rats was mitigated. Meanwhile, the tumor necrosis factor alpha (TNF-α), nuclear factor-kappa B (NF-κB) expressions were significantly down-regulated at protein level by PR intervention. Additionally, the activity of superoxide dismutase (SOD) was elevated, while the content of malondialdehyde (MDA) was lessened in liver tissue. As revealed by immunohistochemistry assay, PR therapy resulted in reduced production of transforming growth factor-βl (TGF-βl). Moreover, it also was attributed to decreased mRNA level of inducible nitric oxide synthase (iNOS) using RT-PCR analysis. These findings demonstrate that puerarin successfully reverses hepatotoxicity in CCl4-induced HF rats via the underlying mechanisms of regulating serum enzymes and attenuating TNF-α/NF-κB pathway for anti-inflammation response, as well as improving metabolic function in liver tissue. [Copyright &y& Elsevier]

Abstract: This study was designed to investigate the potential effects of 14days’ intragastrically given of cinnamon polyphenols (CPS) in treating diabetic mice induced by intraperitoneal injection of streptozotocin (150mgkg−1) and fed high-sugar, high-fat diet. The diabetic mice model was successfully established through determining on fasting blood-glucose (FBG) test. As revealed by glucose oxidase (GOD) and radioimmunoassay (RIA), both dimethyldiguanide (DC, 0.6gkg−1 d−1) and CPS (0.3, 0.6, 1.2gkg−1 d−1) treatments significantly resulted in down-regulation of blood glucose and insulin levels in serum, while the levels of oxidative stress markers were markedly lowered through ELISA assay. Meanwhile, the pathological damage in islet with pancreatic beta cells was ameliorated by treatment of CPS at different doses, as shown in HE stain. At the same time, the treatments also caused notable reduction of iNOS, NF-κB expressions showing in Western blot analysis. These findings demonstrate that cinnamon polyphenols can exert the hypoglycemic and hypolipidemic effects through the mechanisms that may be associated with repairing pancreatic beta cells in diabetic mice and improving its anti-oxidative capacity, as well as attenuating cytotoxicity via inhibition of iNOS, NF-κB activation. [Copyright &y& Elsevier]