颞下颌关节对不同强度加速度反应的分析

目的：研究颞下颌关节在不同强度持续性高正加速度( Gz)作用下的反应情况。方法：雄性Wistar大鼠60只随机分成5组，A组为空白对照；B组地面固定5min；C组固定于离心机转臂上，俯卧位，头向轴心， 1Gz离心5min；D组体位同C组， 10Gz离心30s，G增长率0．5G／s，间隔时 1Gz离心60s，连续每天3次，每周3d，共3周；E组 Gz加载条件每天5次，每周4d，其余参数同D组。各组动物分别取颞下颌关节作光镜观察和扫描电镜观察。结果：A组、B组和C组未见异常，D组髁状突和关节盘胶原纤维排列紊乱，偶见胶原原纤维破坏，凝胶状物质菲薄但基本完整。E组髁状突和关节盘胶原纤维排列紊乱、断裂。凝胶状物质不完整，胶原纤维暴露断裂伴成纤维细胞脱落。结论：高正加速度重复作用对大鼠颞下颌关节的损伤随着暴露剂量的增加而加重。

Changes of temporomandibular joint under +Gz stresses

Objective:To analysis the Changes of Temporom a ndibular Joint(TMJ) Under +Gz Condition. Methods: 60 male Wistar rats were randomly divided into 5 groups( n =12). Group A was normally fed. G roup B was only fixed with rat kept devices for 5 minutes Group C was borne + 1Gz for 5 minutes. Group D was repeatedly exposed +10Gz (each for 30s, onset rat e about 0 5G/s, 3 times/d with +1Gz 1 minute intervals, 3d/wk, 3 weeks in total ) In group E 5 times/d and 4d/wk, other variables is the same as group D Tem poromandibular Joints and masticatory muscles from each group were respectively taken out and observed under microscope and SEM. Results: No abn ormal changes were observed in group A B and C But in Group D and E pathol ogic injuries were seen in TMJ and masticatory muscles in different degrees In group D, it can be seen that the arrangernent disorder disruption of collagen f ibers The gel like substances become very thin but roughly integrated In gr oup E, because most gel like substances disappeared, the dispose and breakdown of collagen fibers of condyle of mandible and Joint disc were found Some fibro blast cells were taken from the condyle Conclusion: The TMJs w ere induced pathologic changes in different degrees under various experimental v ariables The increasing +Gz exposure could lead to the heavier damage of Rat's TMJ