Role of garlic oil and selenium as stimulators to some antioxidant defense system in irradiated male rats

The increased level of lipid peroxide product; malondialdehyde (MDA) in various tissues of irradiated animals, may play a crucial role in damaging effects of exposure to ionizing radiation mediated by reactive free radicals generation. The protective efficiency of oral administration of garlic oil (500 mg/kg b.wt) three times weekly together with a single intraperitoneal injection of selenium (0.5 mg/kg b.wt) weekly for two weeks was examined on some antioxidant defense system as well as ultrastructural study in rats subjected to fractionated doses of gamma radiation up to a dose level of 6 Gy (1.5 Gy day after day). Exposure to gamma radiation induced a significant elevation in the level of malondialdehyde in plasma and liver and non-significant change was observed in superoxide dismutase activity (SOD). Also a significant increase was occurred in hepatic glutathione (GSH) content and glutathione peroxidase (GSHPx) activity. The pretreatment of irradiated rats with garlic oil and selenium caused a significant decrease in elevated level of MDA and a significant increase in the activity of SOD, GSHPx and GSH contents in both blood and liver. Concerning the ultrastructure studies, liver of irradiated rats showed abnormal shape of nucleus and nucleus membrane, swollen mitochondria with ruptured cristae, rupture of endoplasmic reticulum and vaculated cytoplasm, while intestine of irradiated rats exhibited deformed, shortened and abnormal structure of microvilli, accumulation of nuclear chromatin and dilatation of terminal web layer. In group of rats treated with garlic oil and selenium before exposure to gamma radiation, noticeable amelioration in ultrastructure changes of liver and intestine induced by irradiation was observed indicating a beneficial radioprotective role of both garlic oil and selenium