甲状旁腺素对大鼠正畸牙根吸收后修复期破骨细胞的影响

The influence of osteoclasts during the repairs of tooth root in rats model of tooth resorption by intermittent injection of parathyroid hormone(PTH)

目的：探讨皮下间断注射少量甲状旁腺素（PT H ）（1-34）对大鼠正畸牙根吸收后修复期破骨细胞的影响。方法63只雄性6～8周SD大鼠建立正畸牙根吸收动物模型后，随机分为空白对照组、阴性对照组和实验组。空白对照组大鼠不注射任何药物，阴性对照组间断注射6μg/kg生理盐水，实验组皮下间断注射6μg/kg PTH（1-34）（PTH ：1μg/mL）。分别在中断加力0、7、10、14、17、21、25 d处死大鼠取材，免疫组织化学测定牙根修复期压力侧牙周组织中核因子κB受体活化因子配体（RANKL ）表达变化，抗酒石酸酸性磷酸酶（TRAP）染色观察实验区破骨细胞变化。结果中断加力后修复早期仍可见破骨细胞，实验组相对于其他两组破骨细胞数目差异无统计学意义（P＞0．05）；实验组相对于其他两组破骨细胞分化因子表达早期增强，晚期减弱（P＜0．05）。结论皮下间断注射少量PTH（1-34）对牙根修复期仍持续的牙根吸收不会产生抑制作用。

Objective To investigate the role of PT H （1-34 ） on the expression of receptor activator factor of NF-κB ligand （RANKL） in the induction of osteoclasts and its effect to osteoclasts on compression side during the repairs of tooth root in rats model of tooth resorption by intermittent injection of small dose of PTH （1-34） .Methods After the model of tooth resorption was established in rats 6-8 weeks in age ,63 male SD rats were divided in three groups .Rats in the control group were not given injec-tions for any drugs ;The negative control group were given injections for normal saline 6μg/kg subcutaneously every other day ;The experimental group were given injections for PTH （1-34） 6 μg/kg（PTH ：1 μg/mL） subcutaneously every other day ;then rats in every group were killed on the day 0 ,7 ,10 ,14 ,17 ,21 ,25 .TRAP staining for counting TRAP-positive stained osteoclasts ,calculat-ing the mean ;Ligand RANKL immunohistochemistry and using image-pro-plus image analysis system to measure the average opti-cal density value of compression side .Results On the day of discontinuation ,the tooth resorption continued in each group ;the num-ber of osteoclasts between every two arrays there were no significant statistic differences （P〉0 .05）;RANKL immunohistochemis-try ：Compared with control group and the negative control group ,the experimental group significantly increased in early stage ,and reduced in latest stage（P〈0 .05） .Conclusion It indicated that intermittent injection of small dose PTH （1-34） did not cease the rats tooth resorption which occured during the period of tooth repair .