Protective effects of ascorbic acid on hepatotoxicity and oxidative stress caused by carbon tetrachloride in the liver of Wistar rats.

This study was planned to investigate the protective effect of l(+)-ascorbic acid (Vit C) on CCl(4)-induced hepatotoxicity and oxidative stress in the liver of Wistar rats (Rattus Norvegicus, strain Wistar). Twenty-four adult male Wistar rats were fed with standard rat chow diet for 10 days and randomly were divided into four groups of six each as follows: (1) control, (2) CCl(4), (3) "CCl(4) + Vit C", (4) Vit C groups. CCl(4) was applied to rats belonging to CCl(4) and "CCl(4) + Vit C" groups subcutaneously at 1 mg kg(-1) dose CCl(4) for 3 days. Vit C applied to "CCl(4) + Vit C" and "Vit C" group rats intraperitoneally at 300 mg kg(-1) dose for 3 days. All rats were sacrificed and livers were quickly removed on the fourth day of the experiment. MDA, total glutathione (T.GSH) levels and superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GSH-PX) activities were measured in the liver of all groups of rats and also serum alanine amino transferase (ALT) and aspartate amino transferase (AST) activities were detected to determine liver functions in all groups of rats. Histopathological changes were evaluated by light and transmission electron microscopes. In "CCl(4) + Vit C" group, MDA level was significantly decreased (p < 0.05) and SOD, CAT, GSH-PX activities were significantly increased (p < 0.005, 0.01, 0.05) respectively, T.GSH level was significantly increased (p < 0.005) and serum ALT and AST activities were significantly decreased (p < 0.01, 0.05), respectively, when compared with CCl(4) group. These results show that Vit C has a highly protective effect on hepatotoxicity and oxidative stress caused by CCl(4).

Comparison of chemopreventive effects of Vitamin E plus selenium versus melatonin in 7,12-dimethylbenz(a)anthracene-induced mouse brain damage.

In this work, the protective effect of Vitamin E plus selenium (Vit E+Se) and melatonin against 7,12-dimethylbenz(a)anthracene (7,12-DMBA)-induced changes in superoxide dismutase (SOD), glutathione peroxidase (GSHPx), catalase (CAT) and carbonic anhydrase (CA) activities and malonedialdehyde (MDA) levels of mouse brain were compared. 12-month old mice were divided into four groups each including 10 animals. The first group served as control group. The second group was treated with 7,12-DMBA (20 mg/(kg day)). The third group was treated with 7,12-DMBA and Vitamin E (90 microg/(individual day)) and selenium (1.8 microg/(individual day)) simultaneously. The fourth group was treated with 7,12-DMBA and melatonin (4.2 mg/(kg day)) simultaneously. Treatment continued for 21 days after which the mice were sacrificed and brain homogenates were prepared. 7,12-DMBA treated group exhibited significantly decreased levels of brain SOD, GSHPx, CAT and CA activities and increased MDA levels as compared to control. Vitamin E+Se fully or partially restored enzyme inhibition except for SOD. Lipid peroxidation was also reduced in Vitamin E+Se treated group. Melatonin provided a better protection for SOD, GSHPx and CAT, and a plausible protection for CA activity. Protection against lipid peroxidation measured as MDA in melatonin treated group was appreciable although slightly lesser than the protection provided by Vitamin E+Se. The results imply that Vitamin E+Se and melatonin both provide chemoprevention against 7,12-DMBA-induced oxidative stress in mouse brain.