[Biological effects of low dose X-irradiation on human bone marrow mesenchymal stem cells]

Recent studies have shown that low dose X-irradiation shows specific effect different from high dose exposures. However, the biologic responses of bone marrow mesenchymal stem cells (BM-MSC) to low dose X-irradiation have rarely been described in the literature. This study was purposed to investigate the biologic responses of human bone marrow-derived MSC to low dose X-irradiation. The proliferation of cells was tested with MTT assay, so that the cell growth curve was drawn at 1 to 7 days. The expression of survivin mRNA was detected by RT-PCR assay; the BM-MSC DNA damage induced by X-irradiation were detected with mononuclear cell gel electrophoresis. The results indicated that the proliferative ability of BM-MSC exposed to low doses of X rays was obviously enhanced as compared with control group. The low dose X-irradiation caused the damage of DNA in X-ray dose dependent manner. X-irradiation enhanced expression of survivin in MSC. It is concluded that the low dose below 20 cGy of X-irradiation has a promoting effect on survivin expression in BM-MSC. Whether the high expression of survivin plays an important role to resist ionizing radiation needs to be further studied.