Abstract
Purpose: To investigate the effect of whole-body low-dose radiation (10 cGy of 6 MV x-rays) given prior to a challenging dose of 2 Gy x-rays on adaptive response in the liver of rats
Material and methods: Rats were either irradiated with 10 cGy, 2 Gy or 10 cGy 24 h prior to 2 Gy (10 cGy-2 Gy irradiated). Liver samples were analyzed for apoptosis, caspase-3, Bcl-2, by flow cytometry. DNA damage was determined by alkaline comet assay. The protein damage, lipid damage, and expression of endogenous antioxidants, Il-1β, Il-6, and TNF-α were determined by ELISA.
Results: An increase in apoptosis paralleled with increase in DNA damage and expression of Il-1β, Il-6, and TNF-α, protein oxidation, and lipid peroxidation were detected in all irradiated groups. The irradiated rats with 10 cGy-2 Gy and the 2 Gy-irradiated showed the highest effect. The increase in oxidative damage of protein and lipid was accompanied with depletion of endogenous antioxidants. In all cases, the10 cGy-2 Gy irradiated group showed similar or higher effect than the 2 Gy-irradiated group.
Conclusions: Under the present experimental conditions, There is no evidence that 10 cGy-irradiation protected the liver cells against a subsequent higher dose. The significant effect of 10 cGy-irradiation emphasizes the low-dose radiation-associated risk.