细胞凋亡及其相关基因Bcl-2和Bax在大鼠正畸牙槽骨改建中的作用

Apoptosis and the expression of Bcl 2 and Bax during orthodontic alveolar bone remodeling in rat

目的：观察大鼠正畸牙齿移动中牙槽骨的细胞凋亡现象以及凋亡相关基因Ｂｃｌ－２和Ｂａｘ的表达，初步探讨细胞凋亡在牙槽骨改建中的作用。方法：选用２５只健康雄性ＳＤ大鼠，用单簧圈别针簧矫治器推上颌切牙侧向移动，于加力后１、３、５、７ｄ系列观察牙槽骨中细胞凋亡及其相关基因Ｂｃｌ－２和Ｂａｘ的表达，以正常组为对照，用免疫组织化学方法和ＴＵＮＥＬ法进行检测。结果：正常牙槽骨组织中存在凋亡细胞，主要见于骨细胞，呈散在性分布，数量较少。牙齿移动时，压力侧牙槽骨改建活跃，凋亡细胞有增多趋势，而张力侧牙槽骨凋亡细胞呈减少趋势。在成骨细胞、破骨细胞、透明性变区未检测到凋亡细胞。Ｂｃｌ－２和Ｂａｘ在正常牙槽骨细胞均有表达，在压力侧Ｂａｘ的表达强于Ｂｃｌ－２，在成骨细胞和破骨细胞Ｂｃｌ－２的表达强于Ｂａｘ。结论：细胞凋亡及其相关基因Ｂｃｌ－２和Ｂａｘ参与了正畸牙齿移动过程中牙槽骨的改建过程。

Objective:To investigate the role of apoptosis and its related gene Bcl 2 and Bax in rat alveolar bone remodeling during orthodontic tooth movement.Methods:Orthodontic tooth movement of upper incisors was performed in twenty five male SD rats.The histological changes,apoptosis and the expression of Bcl 2 and Bax were observed in the surrounding alveolar bone 1,3,5 and 7 days after orthodontic tooth movement with HE staining,immunohistochemical technic and TUNEL methods .Results:Apoptotic osteocytes were observed in normal rat alveolar bone.During tooth movement,the number of apoptotic cells were increasing in pressed zone and were decreasing in tensed zone.Apoptosis was not detected in osteoblasts,osteoclasts and hyalinization in this study.The immunoreactivities of Bcl 2 and Bax were weak positive in normal alveolar bone.The intensity of immunoreactivities of Bax was stronger than that of Bcl 2 in pressed zone.And the immunoreactivities of Bcl 2 was stronger than that of Bax in osteoblasts and osteoclasts.Conclusion:Apoptosis and its related gene Bcl 2 and Bax participate in alveolar bone remodeling during orthodontic tooth movement.