effects of low-dose gamma radiation on expression of apoptotic genes in rat peripheral blood lymphocyte

Background: exposure to high-dose ionizing radiation is known as a human carcinogen factor, but our information about the effects of low-dose ionizing radiation such as occupational exposures is limited. the main concern of scientific community is biological consequences due to low-dose radiations. objective: this study aims to evaluate the effects of low-dose γ-radiation on expression changes of apoptotic genes (bax and bcl-2) in the rat peripheral blood lymphocytes. material and methods: in this experimental study, 42 adult male rats were classified into 6 groups, which was exposed to various doses values ranged from 20 mgy to 1000 mgy by γ-rays from a co-60 source. blood samples were provided for analysis of gene expression 24 h after gamma radiation by relative quantitative reverse transcription - polymerase chain reaction (rt-pcr). radiation sensitivity of rat lymphocytes was measured by the bax/bcl-2 ratio as a predictive marker for radio-sensitivity. results: the results of this study showed that low dose of gamma radiation can induce down-regulation of bax in rat peripheral blood lymphocytes. despite other mechanisms of cellular radio-protection, changes in expression of these apoptotic genes can be the primary pathway in responses of the lymphocytes radio-protection to the exposure. our study revealed a significant decrease in the bax/bcl-2 ratio at 50 mgy dose compare to control and the other irradiated groups (p < 0.05). conclusion: these results suggest that changes in the bax/bcl-2 ratio especially in radiation workers, as a key factor in apoptosis, can be considered as a biological marker in low-dose gamma radiation.