偏侧咀嚼大鼠咬肌线粒体渗透性转换孔与咬肌细胞凋亡的相关性研究

Research about the interrelation between mitochondrial permeability transition pore and apoptosis on rat masseter muscle after unilateral mastication

目的:探讨偏侧咀嚼大鼠咬肌线粒体渗透性转换孔(Mitochondrialpermeabilitytransitionpore,MPTP)开放程度与咬肌细胞凋亡情况的改变,以及二者的相关性,进一步研究偏侧咀嚼致咬肌功能紊乱的机制。方法:用分光光度法检测线粒体渗透性转换孔道的开放程度;用电镜观察咬肌线粒体以及细胞凋亡形态;用细胞凋亡-Hoechst染色试剂盒测定细胞凋亡指数。结果:实验组拔牙侧线粒体渗透性转换孔道的开放程度均大于实验组非拔牙侧和对照组(P<0.05),其中4周组达到最高。除8周组,其他各实验组拔牙侧细胞凋亡指数均高于实验组非拔牙侧(P<0.05),且2周和6周实验组细胞凋亡指数与对照组差别均有统计学意义(P<0.05)。实验组非拔牙侧MPTP开放程度与咬肌细胞凋亡指数存在直线相关关系(R=-0.49245,P<0.05)。结论:偏侧咀嚼过程中线粒体渗透性转换孔开放的相关信号通路被激活,引起线粒体损伤和细胞凋亡,这可能是偏侧咀嚼致咬肌功能紊乱的发生机制。

Objective： To investigate the changes of the opening level of mitochondrial permeability transition pore （MPTP）, the change of the masseter apoptosis in masseter, as well as the correlation between the two; to research the mechanism about masseter dysfunction induced by unilateral mastication. Methods： The opening level of MPTP was detected with spectrophotometry; the mitochondria and the morphology of apoptotic cells in masseter were observed by electron microscopy; apoptotic index was measured by apoptosis-Hoechst staining kit. Results： 1） Compared with the non-extraction side of the experimental group and the control group, opening degree of MPTP in extraction side of the experimental group was greater （P〈0.05）, and the 4-week group was the greatest. 2） In addition to the 8-week group, the apoptotic index in the other extraction sides of the experimental group was higher than the non-extraction sides （P〈 0.05）, and for the 2-week group and the 6-week group, the difference between the apoptotic index of the experimental group and the apoptotic index of the control group was statistically significant （P〈 0.05）. 3） The opening level of MPTP and masseter apoptotic index ex- ists a linear correlation in the non-extraction side of the experimental group （R =-0.49245, P〈 0.05）. Conclusion： Signaling pathway related to the opening of MPTP is activated, causing mitochondrial damage and apoptosis, which may be one of the mechanisms of masseter dysfimction induced by unilateral mastication.