慢性不可预知性刺激后大鼠咀嚼肌超微结构的变化

Changes in ultra-structures of masseter induced by chronic unpredictable stress in rats

目的研究观察慢性不可预知性刺激后大鼠口颌面咀嚼肌超微结构的变化。方法12周雄性Wistar大鼠32只随机分为实验组和对照组各16只,各组随机分为3周和6周时间组,每组分别为8只。实验组建立慢性不可预知性应激(CUS)动物模型,对照组正常饮食不加任何刺激。3周、6周时间点分别处死3周及6周组大鼠,取双侧咬肌、翼内肌常规HE染色,透射电镜下观察大鼠咀嚼肌超微结构变化。结果实验组大鼠咀嚼肌出现超微结构损伤,表现为肌丝排列紊乱、Z线弯曲、线粒体变性等情况,6周实验组损伤较3周实验组明显。结论长期慢性不可预知性应激刺激可导致大鼠咀嚼肌出现超微结构损伤。

Objective To study the effect of chronic unpredictable stress on ultra-structures of masseter in rats. Methods Thirty-two male Wistar rats, at the age of 12 weeks, were randomly divided into experimental group and control group. Each group was divided into 3-week subgroup and 6-week subgroup（ 8 rats in each group）. A model of rats with chronic unpredictable stress was established for the experimental group. Rats in the 3- and 6-week subgroups were killed after 3 and 6 weeks, respectively. Some of the masseter and internal pterygoid muscles of rats were cut, and changes in ultra-structures of masseter muscle were observed under transmission electron microscope. Results Under transmission electron microscope, ultra-structures of masseter muscle cells changed significantly in the experimental group. The myofilament was deranged, the ＂z-line＂ was warped, and mitochondria with loss and degrade of cristae were found in 3-week subgroup. Severe vacuolus changes in mitochondria were observed in 6-week subgroup. No obvious change was found in the control group. Conclusion Chronic emotional chronic unpredictable stress induces injury of masseter in rats at ultra-structure level.