Antioxsidant status in chicken liver after exposure to low dose gamma radiation

Although radiation is a known producer of reactive oxygene species in living systems it has been shown that acute low dose ionizing irradiation induced various antioxidant mechanisms, enzymatic and non-enzymatic, that defend cells from oxidative stress. It is also shown in increased level of antioxsidant substances such as superoxide dismutase, catalase, glutathione peroxidase and glutathione in different organs after low dose irradiation. However, newly studies of low dose radiation in chickens were performed mostly on hatchability, body weight and egg fertility in commercial meat chicken line. Whereas, there are lack of results on antioxsidant status in chicken embryo and chicks hatched from irradiated eggs the aim of this study was to investigate low dose radiation effects upon antioxidant status in chicken liver after low dose gamma irradiation. The eggs of a heavy breeding chickens COBB 500 were irradiated with the dose of 0, 3 Gy gamma radiation (source 60Co) on the 19th day of incubation. Liver samples were taken on 3, 6, 24, 48, 72 and 96 h after irradiation. The thiobarbituric acid reactive substances (TBARS), glutathione levels (GSH) and activity of glutathione peroxidase (GSH-Px), superoxide dismutase (SOD) and catalase (CAT) were measured spectrophotometrically. The GSH levels increased in the liver of chickens hatched from irradiated eggs at 6 hours after irradiation and decreased 48 h after irradiation. Antioxsidant enzyme activities for GSH-Px and SOD significantly decreased in the liver of chickens hatched from irradiated eggs 48 h after exposure to the dose of 0.3 Gy. TBARS levels and CAT activity during the experiment were not statistically different when they compared to controls. Obtained results indicated that acute irradiation of chicken eggs on the 19th day of incubation with the dose of 0.3 Gy gamma radiation could have a different effects on antioxidant parameters in embryo liver of chicken, i.e. the enzyme activity of SOD and GSH-Px were decreased, however, catalase and TBARS were not affected by the irradiation. The level of glutathione was firstly increased and after that it decreased. This findings suggest that glutathione is an important antioxidant in the protection of liver cells against ionizing radiation and that this dose does not stimulate antioxidants enzymes in the same tissue.