Objective The aim of this study is to investigate the effects of irradiation on the proliferation and differentiation of MC3T3-E1 osteoblastic cells. Methods MC3T3-E1 cells were irradiated 24 h after initial seeding. Gamma-radiation was administered at 0, 4, and 8 Gy as single doses by using a 60Co source. Cell proliferation was assessed at days 1, 3, 5, and 7 post-irradiation by using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenylte-trazolium bromide assay. The collagen secretion of the cells was measured through sirius red staining at day 12 post-irradiation. The expressions of osteogenesis-related genes were assessed through real time fluorescence quantitative polymerase chain reaction at day 16 post-irradiation. The matrix mineralization caused by cells was evaluated through alizarin red staining at day 28 post-irradiation. Results The cells exposed to 4 Gy or 8 Gy demonstrated significantly lower proliferation rates compared with the non-irradiated group. Doses of 4 Gy or more significantly inhibited the expressions of osteogenesis-related genes (Osterix and osteocalcin). Collagen secretion and cell mineralization were significantly reduced by the 8 Gy dose. Conclusion 60Co γ-rays dose-dependently suppress the proliferation, collagen secretion, and mineralization of MC3T3-E1 cells. Furthermore, radiation seems to dose-dependently inhibit the expressions of osteogenesis-related genes of the cells.%目的：观察60Coγ射线对MC3T3-E1成骨前体细胞增殖和分化能力的影响。方法 MC3T3-E1细胞接种24 h后进行60Coγ射线照射，单次照射剂量分别为0、4、8 Gy。辐射后第1、3、5、7天，采用噻唑蓝比色法检测细胞的增殖能力；辐射后第12天，用黏胶纤维红染色法检测细胞的胶原分泌情况；第16天，用实时荧光定量聚合酶链反应检测细胞成骨相关基因mRNA的表达；第28天，采用茜素红染色及定量分析检测细胞基质的矿化能力。结果与对照组（0 Gy）相比，4、8 Gy剂量的射线可以明显降低MC3T3-E1细胞的增殖，并下调其Osterix和骨钙素基因的表达；8 Gy剂量的射线可以明显抑制细胞的胶原分泌和基质矿化能力。结论60Coγ射线可以降低MC3T3-E1细胞的增殖、胶原分泌及基质矿化能力，并下调其成骨相关基因表达，且随辐射剂量增加，其作用增强。
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