多西环素对大鼠正畸移动牙根面骨型胶原酶表达的影响

目的:通过建立正畸牙根吸收动物模型,检测牙根面及根周组织中骨型胶原酶(MMP-13)的分布和表达,研究多西环素(DOXY)对根吸收及骨型胶原酶表达的影响。方法:选用SD大鼠36只建立正畸牙移动根吸收的动物模型,随机分为空白对照组、注射DOXY对照组、正常牙加力组、注射DOXY加力组。在加力的0天、7天、10天、14天分别处死各组大鼠。并取相应时段的标本制作组织切片,应用免疫组化技术检测分析各组中骨型胶原酶(MMP-13)在第一磨牙根吸收组织中的定位表达,检测多西环素对根周组织内骨型胶原酶表达及分布的影响。用计算机图像分析技术定量比较上述试验结果。结果:在多西环素的影响下,在第7天和第10天给药受力组的MMP-13的阳性表达低于受力不给药组。给药受力组MMP-13的阳性表达在第10天更低(P0.01)。两实验组MMP-13的阳性表达都在第10天到达峰值后第14天趋于平稳。结论:多西环素可能作为骨型胶原酶的抑制剂对破骨细胞的募集及牙根吸收有抑制作用。

An experimental study on expression of collagenase-3 during orthodontic tooth movement in rats with doxycycline administration

Objective To investigate the expression and the localization of MMP-13 in root-resorbing tissue during experimental tooth movement with doxycycline （DC） administration,to elucidate the protein changes and mechanism of root resorption induced by orthodontic tooth movement.All of these could give an evidence which maybe used regulate orthodontic tooth movement more efficiently.Methods Animal models of experimental orthodontic tooth movement in Sprague-Dawley rats were established.36 male rats were randomly assigned to four groups.Nine animals served as untreated controls.Nine animals were only administered DC for 7 days,by means of injection on rat＇s back subcutaneously daily.In 18 animals the maxillary first molar was moved mesially by a continuous and constant reciprocal force of 50g from Sentalloy？ closed-coil springs.In 9 of these animals DC was administered at the time of appliance insertion and throughout the experiment.The animals were sacrificed 7,10 or 14 days after force application.An area including the mesial aspect of the mesial root and the adjacent interradicular alveolar bone was histomorphometrically evaluated.The expression and localization of MMP-13 were examined by immunohistochemical technology.Computer image analysis was performed to evaluate all of these results.Results The expression of MMP-13 presents a peak at day 10 and decreased at day 14.The doxy-ortho group demonstrated significantly fewer MMP-13-positive cells on the root surface than the ortho group at day 7 and day 10.Conclusion As an effective collagenase inhibitor,DC may have an inhibitory effect on the recruitment of osteoclasts and orthodontically induced resorptive activity.