咬合力影响大鼠下颌骨微结构发育的时序观察

Time series observation on microstructure development of mandibular bone under different occlusal force in rats

目的:观察不同咬合力下大鼠下颌骨微结构发育的时序性变化及差异。方法:取23d龄雄性SD大鼠63只,随机分为基线(Baseline)组、软食(SD)组和硬食(HD)组,分别在喂养不同硬度食物后第0、2、4、6、8周各处死7只,应用Micro-CT重建分析下颌骨感兴趣区域的微结构。结果:相比HD组,SD组骨体积分数(BV/TV)及骨小梁厚度(Tb. Th)在第4周后显著减小(P <0. 05);骨表面积体积比(BS/BV)及骨小梁间距(Tb. Sp)在第4～6周显著增加(P <0. 05)。结论:大鼠下颌骨发育过程中,咬合力降低会导致骨量减少,其微结构变化特点与干预时间密切相关。

Objective: To study the microstructure development of mandibular bone in rats on timing sequence and under different occlusal force. Methods: 63 male SD rats aged 23 days were randomly divided into three groups( n = 7) : Baseline group,soft-diet( SD)group and hard-diet( HD) group. 7 rats were killed at week 0,2,4,6 and 8 respectively after feeding the food with different hardness.Micro-CT was used to reconstruct and analysis microstructure of the region of interest in mandible of the rats. Results: Compared with HD group,bone volume/total volume( BV/TV) and trabecular thickness( Tb. Th) decreased significantly after 4 th week( P < 0. 05),the bone surface/bone volume( BS/BV) and trabecular separation( Tb. Sp) increased significantly during the 4 th to the 6 th week( P <0. 05). Conclusion: In the process of mandibular development in rats,reduction of occlusal force may lead to reduction of bone mass,and the changes of microstructure are closely related to the time of intervention.