Protective Effect of Oral Ascorbic Acid (Vitamin C) Against Acetaminophen-Induced Hepatic Injury in Rats

The incidence of acetaminophen-induced hepatotoxicity is reported to be on the increase, with limited therapeutic or chemoprophylactic options. In the present in vivo study, single daily oral doses (100 - 500 mg/kg) of ascorbic acid (ASC) were investigated for their protective effects against acetaminophen (APAP)-induced hepatotoxicity in 4 groups of rats made up of 6 rats per group for 14 days. Also, effects of the doses on body weights taken on the 1st, 7th and 15th day of the experiment were also investigated. On the 15th day, blood samples for serum ALT, AST and FBG assay were collected through cardiac puncture under inhaled diethyl ether anaesthesia. Rat livers were also studied for histopathology. Results showed that treatment with APAP intraperitoneal injection induced significant (P<0.001) elevation in the serum levels of ALT and AST while inducing significant (P<0.05) decrease in the serum FBG. The hepatotoxicity was also corroborated by the histopathological lesion of lipid peroxidation characterized by diffuse ballooning degeneration with lymphocytic infiltration. Significant (P<0.01) weight loss and hypoglycaemia were also associated with APAP-induced hepatotoxicity. However, these alterations were attenuated in ASC pretreated rats dose dependently. Also, APAP-induced hypoglycaemia and weight loss were significantly (P<0.01, P<0.001) enhanced by ASC in dose related pattern. Thus, results of this study showed that 100 - 500 mg/kg/day was protective against APAP-induced hepatotoxicity, effect which could have been mediated via its inherent free radical scavenging and/or free radicals generation inhibiting activities

Metformin: An effective attenuator of risperidone-induced insulin resistance hyperglycemia and dyslipidemia in rats

332-338The use of atypical antipsychotics in the clinical management of schizophrenia and schizoaffective disorders has been associated with the development of insulin resistance. The present study evaluates the possible individual ameliorating effect of single daily oral treatments with 20 mg/kg/day of metformin and 0.1 mg/kg of glibenclamide in two groups of Wistar rats pretreated with 0.2 mg/kg of risperidone for 60 days. Two additional groups of rats were only treated with 0.2 mg/kg of risperidone and 10 mL/kg of distilled water, respectively, also for 60 days. Results showed that oral pre-treatment with metformin significantly attenuated increases in the weight gain pattern, fasting glucose, fasting plasma insulin, serum triglyceride and total cholesterol levels that were elevated by risperidone treatment. Metformin also significantly reduced glycosylated hemoglobin concentration, fasting insulin-glucose ratio and fasting insulin resistance index. Conversely, oral pre-treatment with glibenclamide for 60 days did not significantly reduce any of the measured parameters except for glycosylated hemoglobin concentrations. Thus, results of this study showed that 20 mg/kg of metformin effectively ameliorated the development of risperidone-induced insulin resistance and dyslipidemia which was mediated via improvement in insulin resistance. This study provides insight into the therapeutic potential of metformin in preventing risperidone-induced insulin resistance diabetes mellitus and dyslipidaemia