Effect of low-dose X-rays on the liver of whole-body irradiated rats

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.