The Induction of Radioadaptive Response by ³H-Thymidine in Mouse Fibroblast Cells

Radioadaptive response is a biological defense mechanism that is induced by low-dose ionizing irradiation for cellular resistance to the genotoxic effects of subsequent irradiation. Although radioadaptive response was first identified in human lymphocytes pretreated with low concentration of ³H-thymidine, molecular mechanism of the induction of radioadaptive response by ³H-thymidine is still obscure. We have reported the effect of pre-irradiation with 2 cGy X-rays prior to the challenging irradiation with 3 Gy on the induction of chromosome aberrations in quiescent mouse m5S fibroblasts. In this study, we have shown that the radioadaptive response is mediated through the pathways involving protein kinase C by using RNA interference method. We examined the induction of radioadaptive response by ³H-thymidine in mouse m5S fibroblasts, and found that radioadaptive response is induced in mouse fibroblasts by the treatment with low concentration of ³H-thymidine for a few days.