大鼠前牙移动后保持过程中IGF-I在牙周组织张力侧的表达及作用

Expression and significance of IGF-1 in the periodontium on the tension side during retention stage after anterior tooth movement in rats

[目的]研究大鼠前牙保持阶段,张力侧牙周膜中IGF-I的表达,探讨IGF-I在大鼠前牙正畸后保持阶段对牙周组织改建中的作用,分析大鼠前牙加力后最短保持时间,推测临床正畸治疗后最短保持时间。[方法]选择雄性大鼠36只,随机分为6组,空白对照组及实验组5组,按保持时间长短,分别为保持1、3、7、14及21 d组,每组6只。实验组在建立大鼠保持期模型后,按分组要求处死大鼠,空白对照组则同条件饲养7 d后直接处死。用免疫组化法分析大鼠前牙牙周膜张力侧IGF-I的表达。[结果]保持1、3、7、14 d组IGF-I表达呈时间依赖性且表现为下降趋势,保持21 d组与空白对照组相比,差异无统计学意义(P <0. 05)。[结论]IGF-I参与保持期大鼠前牙牙周膜张力侧的骨改建,并与保持时间呈重度相关,推测保持约21 d后牙周组织张力侧骨改建基本完成。

〔Objective〕This study was carried out aiming to investigate the expression of IGF-1in the pericementum on the tension side of the anterior teeth during retention stage in rats in addition to exploring the significance of IGF-1on periodontal reconstruction in the period of retention after orthodontic treatment of anterior teeth in rats so as to analyze the shortest retention time of anterior teeth after applying force and also to predict the shortest retention time after orthodontic treatment in clinical practice.〔Methods〕A total of36male SD rats were selected and randomly divided into6groups of one control group and5experimental groups with a total number of6rats in each one.The latter5experimental groups were subgrouped according to the length of retention,including1day retention group,3day retention group,7day retention group,14day retention group and21day retention group.After the establishment of rats model during the retention stage,rats were sacrificed in the experimental groups according to each group requirement.Furthermore,rats in the control group were put to death directly following7days of feeding under the same condition.Immunohistochemistry was the selected modality to measure the expression of IGF-1in the pericementum on the tension side of anterior teeth in rats.〔Results〕IGF-1expression showed a time-dependent decrease in the1day retention group,3d retention group and7d retention group.However,there was no significant statistical difference in the comparison of the 14 day retention group and the 21 day retention group with the control group(P<0.05).〔Conclusion〕IGF-1is involved in bone remodeling of the pericementum on the pressure side of anterior teeth during retention stage in rats with a high correlation to the retention time.Bone remodeling of the periodontium on the tension side is speculated to be completed basically after retention for about14d.