Biological Changes on theCompressing Side of Orthodontic Teeth Stimulating by Soft laser

目的：研究在弱激光作用下接受正畸力作用的牙齿的压力侧出现的生物学变化，为临床应用弱激光加速牙齿移动提供理论依据。方法：实验动物分2组，每组20只。A组动物接受正畸力，B组动物除接受正畸力之外，还接受弱激光照射。采用免疫组化检测层连蛋白的组间表达变化，采用原位杂交检测RANKL(receptor activator of NF-kB ligand)mRNA的组间表达变化。结果：免疫组化结果表明，新生血管活跃的高峰期出现在接受正畸力的第7d。与A组相比，接受弱激光照射的B组呈现层连蛋白的高表达。同样，与A组相比，原位杂交检测发现在接受弱激光照射的B组中，正畸牙压力侧呈现RANKL mRNA的高表达。结论：弱激光照射后能够促进正畸牙压力侧血管新生(呈现层连蛋白高表达)，从而促进破骨细胞的分化激活。此外弱激光还能够促进破骨细胞活化因子RANKL的表达，增强正畸牙压力侧的破骨细胞的活性，加快骨改建。

Biological Changes on the Compressing Side of Orthodontic Teeth Stimulating by Soft laser

Objectives:To investigate the biological changes on the compressing side of orthodontic teeth stimulated by soft laser and provide the information on the mechanism of soft laser promoting the orthodontic teeth movement.Methods:Immunohistochemistry and In-situ hybridization were employed to detect the changes of Laminin expression and the RANKL(receptor activator of NF-kB ligand) mRNA expression between group A,consisting of 20 wistar rats which received simulated orthodontic treatment: mesially moving the upper first molar with two incisors as the anchorage and group B,which,specially,not only received simulated orthodontic treatment,but the irradiation of soft laser,15mins per day, during the experimental period.Results:By Immunohistochemistry,Obvious changes in blood vessel density and distribution,indicated by the Laminin expression,were firstly seen at 7 days which seemed to be a peak time for the angiogenesis in the alveolar bone remodeling region,during orthodontic tooth movement,in Group A.The histological finding of blood vessel distribution in-group B is similar to that found in the group A.But compared with group A,the blood vessel density that is immune-reactive to laminin was stronger.By in-Situ hybridization,the stronger signals of RANKL were detected in group B which received soft laser irradiation than in group A.Conclusions:Soft laser stimulate angiogensis indicated by the expression level of Laminin, thus indirectly stimulate the differentiation and activate the osteoclast.The stronger expression of RANKL in group B,compared with that in group A,also indicate the stimulating function of soft laser on the formation and development of ostecolast which is critical for bone remodeling during orthodontic tooth movement.