Study of Some Biochemical and Molecular Changes Induced by Radiation Hormesis in Testicular Tissues of Male Rats

With the development of modern nuclear science and technology as well as the peaceful use of atomic energy and radioisotopes, we examined the possible benefit effects of exposure of the whole body to low dose gamma irradiation for long term (radiation hormesis) on the status of some antioxidant defense system, molecular and histological changes in the rodent testicular tissues using two different low doses of ? irradiation. Thirty adult male albino rats were used in this study, which were divided into three groups of 10 rats each. The first group was maintained as control whereas groups two and three were exposed to fractionated 20 and 60 mGy whole body gamma radiation, respectively 3 days/week for four weeks (with accumulated doses 0.25 Gy and 0.72Gy, respectively). The biochemical: malondealdhyde (MDA), superoxide dismutase (SOD), reduced glutathione (GSH) and testosterone, molecular (Caspase-3 activity and double strand DNA breaks in testicular tissues by comet assay) and histological estimations were investigated. The results showed significant (P<0.05) increase in MDA level and caspase-3 activity, while a significant decrease (P<0.05) in superoxide dismutase (SOD) activity and reduced glutathione (GSH) level and testosterone level in both irradiated groups compared to control group. Moreover, irradiation treatment significantly increased the DNA damage of testes in a dose-dependent manner as observed by comet assay parameters compared to the control. It was concluded that the whole body exposure of animals to low doses gamma radiation did not detect any beneficial effects to radiation hormesis in testicular tissues which confirm sensitivity of testes to low doses of radiation.