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目的 研究小鼠下颌第一磨牙萌出过程中核因子κB激活受体的配体(receptor activator of nuclear factor-kappa B ligand,RANKL)和骨保护素(osteoprotegerin,OPG)的表达,并探索其表达与破骨细胞活动性之间的关系.方法 分离第1.5天～第14.5天小鼠的下颌骨,连续切片,抗酒石酸酸性磷酸酶染色显示磨牙萌出中破骨细胞的活动,免疫组化法显示RANKL和OPG的表达.结果 冠方骨组织中单位面积破骨细胞数在第1.5天和第9.5天分别出现两次高峰(分别为5.04和4.40),根方也在第1.5天和第9.5天出现两次高峰(分别为9.20和6.16),而侧方破骨细胞峰值出现在第3.5天和第9.5天(分别为7.48和5.75).RANKL表达越丰富,破骨细胞数量越多,破骨活动越活跃,OPG的表达越少.结论 磨牙牙胚的生长可出现两个生长高峰,在此过程中磨牙向冠方的发育速度相对平稳,而根向和侧向则可能出现一过性的加速生长态势;RANKL和OPG的表达与破骨细胞的活动参与了小鼠下颌第一磨牙萌出过程.

Objective To investigate the immunolocalization of receptor activator of nuclear factorkappa B ligand(RANKL)and osteoprotegerin(OPG),and to explore the correlation between their expressions and activity of osteoclast during first mandibular molar eruption.Methods Mouse mandibles dissected from postnatal day 1.5 to 14.5 were stained respectively for muhinucleated osteoclasts using tartrate-resistant acid phosphatase(TRAP)staining,and RANKL and OPG protein expression was examined by immunohistochemical staining.Results The two peak values of osteoclast/acrage in the occlusal and basal region were both observed on the P1.5 and P9.5:while the two peak values in the lateral region were on P3.5 and P9.5.During the mouse molar eruption,burst of osteoclastogenesis was associated with high expression of RANKL and low expression of OPG.Conclusions RANKL and OPG could have a close relationship with the osteoclast activity and two developmental apexes were observed during the molar eruption.The occlusal movement was relatively stable,meanwhile the temporarily accelerative movement to the basal and lateral regions could occur.