探讨低能量激光照射是否对体外培养的成骨细胞增殖过程中的hedgehog信号通路产生影响，揭示低能量激光照射促进骨形成的分子学机制，为其在口腔种植的临床应用提供理论依据。体外培养小鼠成骨样细胞系MC3T3-E1，用hedgehog信号通路增强剂N端hedgehog重组蛋白（N-Shh）、hedgehog信号通路抑制剂环巴胺对低能量激光照射后的MC3T3-E1进行干预，随机分为4组，采用细胞计数，MTS，流式细胞术检测照射后12，24，48，72 h成骨细胞的增殖活性。结果显示，与激光照射组相比，激光照射+N-Shh组的细胞增殖活性明显增加，激光照射环巴胺组的细胞增殖活性明显降低，激光照射环巴胺组的细胞增殖活性仍高于对照组。研究发现低能量激光照射活化了成骨细胞增殖过程中的hedgehog信号通路，hedgehog信号通路是参与低能量激光照射调控成骨细胞增殖的通道之一。

The aim of the present study is to examine whether low level Ga-Al-As laser irradiation has an effect on hedgehog signaling pathway during osteoblast proliferation in vitro. The molecular mechanism of how low level Ga-Al-As laser irradiation promotes bone formation is explored. This study provides a theoretical basis for the clinical application of low level Ga-Al-As laser irradiation in oral implant. Mouse osteoblastic cell line MC3T3-E1 is cultured in vitro. The cultures after laser irradiation are treated with recombinant N-terminals sonic hedgehog (N-Shh) or hedgehog inhibitor cyclopamine respectively. The experiment is divided into 4 groups. The proliferation activity is detected by cell counting, MTS, flow cytometry at 12, 24, 48, 72 h after laser irradiation. Proliferation activity of laser irradiation and N-Shh group is remarkably increased compared with those of laser irradiation group. Proliferation activity of laser irradiation and cyclopamine group is remarkably decreased compared with those of laser irradiation group, meanwhile proliferation activity of laser irradiation and cyclopamine group is remarkably increased compared with those of control group. These results suggest that low level Ga-Al-As laser irradiation activate hedgehog signaling pathway during osteoblast proliferation in vitro. hedgehog signaling pathway is one of the signaling pathways by which low level Ga-Al-As laser irradiation regulates osteoblast proliferation.