Oxidative stress produced by free radicals has been implicated in the pathogenesis of acute liver injury. The aim of our study was to investigate whether melatonin, a potent antioxidant, could attenuate acute and chronic hepatic injury in rats. Acute liver injury was induced by two consecutive intra peritoneal (i.p.) injections of thioacetamide (TAA; 300 mg/kg, i.p.) at 24 h intervals. Chronic liver injury was induced by (TAA, i.p. injections for 6 weeks twice weekly, 50 mg/kg). Treatment with melatonin (3 mg/kg/daily, i.p.) was initiated 24 h prior to and for 6 weeks post TAA intake. Rats in normal control group received intra-peritoneal injections of normal saline at the same dose and frequency as those in treatment groups. At the end of experiment, animals were sacrificed, liver was removed and weighed, and ratio to body weight was calculated. Serum activities of alanine aminotransferase (ALT), aspartate aminotransferase (AST), reduced glutathione (GSH) and malondialdehyde (MDA) concentration in liver homogenates were assessed. We found that the acute and chronic experiments, liver weight, as well as liver weight/body weight ratio, ALT, AST, GSH and MDA concentration were lower in rats treated with TAA + melatonin compared to acute and chronic TAA groups. Liver histology was significantly improved and the mortality in the melatonin-treated rats was decreased indicating decreased oxidative stress and inflammation. In conclusion both models results suggest that melatonin may be utilized to reduce liver injury associated with oxidative stress.

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The aim was to study the influence of albumin supplementation on the changes of the kidney function and structure in cirrhotic rats induced by common bile duct ligation (BDL). Twenty-four male albino rats weighing 200-250 g were divided into Group I: 6 rats underwent laparotomy alone, and the bile duct was only dissected from the surrounding tissue; Group II: 6 rats underwent a sham operation and received 2% albumin in their drinking water; Group III: 6 rats were subjected to bile duct ligation only; and Group IV: 6 rats were subjected to bile duct ligation and received a daily albumin 2% in drinking water. All rats were sacrificed after 4 weeks. We measured the liver and kidney functions and oxidative stress markers in the renal tissue and conducted a histological evaluation of the liver and kidney. The liver enzymes were decreased, but there was no significant difference in the bilirubin levels in group IV compared to group III. There was a significant elevation of serum creatinine in group III compared to group II, and serum creatinine was attenuated in group IV. The renal tissue catalase activity and reduced glutathione, as well as the nitric oxide levels, were significantly increased in group IV and were elevated in group III. Histologically, the livers of group IV showed degeneration and inflammatory cell infiltration with regeneration areas in which normal hepatocytes appeared. The kidneys of group IV showed recovery as well as areas of inflammatory cell infiltration. Some tubules appeared with normal epithelial lining. In conclusion, the results suggest that albumin partially improves the renal functions and structures after their disturbances as a result of BDL.

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