心理应激对大鼠颞下颌关节盘和翼外肌微结构的影响

Effect of psychological stress on disk of temporomandibular joint and lateral pterygoid muscle microstrueture in rats

目的观察心理应激及实施对抗措施对大鼠颞下颌关节（tempommandihular joint，TMJ）盘及翼外肌的影响，为临床防治颞下颌关节病（temporomandibular disorders，TMD）提供实验理论依据。方法采用交流箱心理应激大鼠动物模型，并在应激前后分别应用抗焦虑药物，去除应激源等措施。运用透射电镜、扫描电镜分别观察施加对抗措施前后空白对照组、心理应激组（PS组）、心理应激加注射抗焦虑药物地西泮组（PS＋DI组）大鼠翼外肌和TMJ盘的傲结构：结果透射电镜显示PS组1，3，5周时大鼠翼外肌出现程度不同的肌纤维线粒体水肿、基质密度降低、线粒体嵴减少；去除应激源恢复各组、PS＋DI组1，3，5周肌纤维线粒体嵴和基质密度正常。扫描电镜显示PS组1周时大鼠关节盘表面部分滑膜脱落，3周时大鼠关节盘表面胶原纤维出现大小不等的条状磨损样变，5周关节盘表面胶原纤维错乱；去除应激源恢复各组、PS＋DI组1，3，5周关节盘无明显微结构改变.结论施加对抗措施能有效对抗心理应激对TMJ的影响，可为临床治疗应激引起的TMD提供借鉴。

Objective To observe the influence of psychological stress and countermeasure implementation upon the temporomandibular joint （TMJ） articolar disc and external pterygoid muscle in rats, providing experimental and theoretical evidence for clinical treatment of psychological stress-induced temporomandibular disorders （TMD）. Methods The animal models treated by psychological stress induced by alternating current box were established. Before and after subjected to psychological stress,rats were given anxiolytic drugs to eliminate stressors. For all the rats in control group, psychological stress group （ PS group ）, and psychological stress plus anxiolytie drug injection group （ （PS ＋ DI） group）, the microstructure of TMJ articular disc and external pterygoid muscle the changes in RNA expression of interleukin-1 （ IL-1 ） were investigated by using transmission electron microscope （TEM）,scanning electron microscope （SEM） and RT-PCR methods, respectively. Statistical analysis was performed upon the obtained test results. Results The TEM showed pathlogieal changes in rats＇pterygoid muscles of PS group at 1,3 and 5 weeks,including edema,reduction of substrate density and microchondrial cristae. Instead, these structures were all showed normal in the group of PS ＋ DI and recovering group after removal of stressor. For the rats in PS group,SEM observation revealed that partial synovium of articular disc began to disintegrate 1 week after psychological stress. Strip-like wear degenerations were shown in the surface collagenous fiber in articular disc 3 weeks later,and the surface collagenous fibers in articular disc were arrayed in disorder 5 weeks following stress treatment. No significant microslructural changes in articular disc were observed in all stressor-eliminating groups and （PS ＋ D1） group 1,3 ,and 5 weeks following stress treatment. Statistical significance was noted in RNA expression level of IL-1 between PS group and PS ＋ DI group （P 〈 0.05 ）. In addition, there was significant difference in IL-1 expression between PS group and all stressor-eliminating groups. Conclusion The implementation of countermeasures effectively counteracted the influence upon TMJ induced by psychological stress, and provided possible resolutions for the clinical treatment uf TMD induced by psychological stress.