牙移动致大鼠牙周鲁菲尼小体超微结构改变的透射电镜观察

Changes of periodontal Ruffini＆#39;s corpuscle induced by experimental tooth movement in rats

目的 比较不同类型牙移动所致牙周鲁菲尼小体超微结构的变化,探讨力学环境改变对牙周机械感受器的影响.方法 28只8周龄SD大鼠用随机数字表分为空白对照组（4只）、非拔牙组（12只）和拔牙组（12只）,后两组再细分为3、14、28 d亚组（每亚组4只）.非拔牙组：移左上和右下第三磨牙向远中,其中上颌左侧第三磨牙为有对（牙合）牙的移动牙,上颌右侧第三磨牙为移动牙的对（牙合）牙;拔牙组：拔除下颌双侧第三磨牙并移左上第三磨牙向远中,其中上颌左侧第三磨牙为无对（牙合）牙的移动牙,上颌右侧第三磨牙为无对（牙合）牙的牙齿;空白对照亚组不拔牙,不进行任何处理.实验各时间点透射电镜观察大鼠上颌双侧第三磨牙远中根牙周鲁菲尼小体的超微结构.结果 非拔牙组主要改变为轴质内线粒体退变和分布异常,28 d可恢复,移动牙的对（牙合）牙（上颌右侧第三磨牙）的超微结构表现较有对（牙合）牙的移动牙（上颌左侧第三磨牙）变化轻;拔牙组主要为施万细胞鞘缺失或异常突起,28 d仍未恢复,无对（牙合）牙的牙齿（上颌右侧第三磨牙）的超微结构与无对（牙合）牙的移动牙变化类似（上颌左侧第三磨牙）,但略轻.结论 牙移动及咬合改变均可致鲁菲尼小体超微结构变化,说明牙周力学环境改变可能影响鲁菲尼小体的机械感受功能.

Objective To compare the ultra-microscopic changes of periodontal Ruffini＆#39;s corpuscle induced by different patterns of tooth movement,and investigate the influence of different changes of the periodontal mechanical environment on the periodontal mechanoreceptor.Methods Thirty-two eight-weeks-old SD rats were divided into control group（n=4）,none-extraction group（n=12） and extraction group（n=12）,and none-extraction group and extraction group were further divided into three subgroups,namely 3 day and 14 day and 28 day.For control group,no intervention was performed.For none-extraction group and extraction group,the following interventions were conducted.In none-extraction group,the maxillary left and mandibular right third molars were moved distally.In extraction group,the maxillary left third molar was moved distally,and the bilateral mandibular third molars were extracted.The ultra-structures of periodontal Ruffini＆#39;s corpuscle in the periodontal ligament of the distal root of the bilateral maxillary third molars were observed under the transmission electron microscope.Results The ultra-structrural changes in the none-extraction group were mainly characterized by degeneration or abnormal distribution of mitochondria in the axon terminal,which were almost recovered at 28 d.In the extraction group,the changes were mainly characterized by deficiency or abnormal elongation of the Schwann sheath and were not recovered at 28 d.Conclusions The ultra-structures of periodontal Ruffini＆#39;s corpuscle might be influenced by tooth movement and occlusal changes,and the mechanorecepting function of it might be affected by changes of the periodontal mechanical environment.