内质网应激对偏侧咀嚼大鼠髁突软骨细胞的影响

Effects of endoplasmic reticulum stress response on condylar chondrocytes in rats with unilateral mastication

目的研究内质网应激反应在偏侧咀嚼大鼠髁突软骨细胞凋亡中的作用,分析内质网应激反应相关蛋白因子的代谢变化。方法将96只3周龄雄性SD大鼠,随机分为实验组及对照组各4组。建立左侧单侧磨牙缺失的动物模型,并于拔牙后1d、7d、14d、28d处死。HE染色观察髁突软骨的形态学变化,RT-PCR方法检测各组大鼠左、右侧髁突软骨细胞中各时间点的CHOP和caspase-12的含量变化。结果HE染色显示实验组髁突软骨正常结构分层逐渐模糊,纤维断裂,细胞排列紊乱、数量减少,软骨细胞可见空泡性变。RT-PCR结果显示,实验组左侧CHOP和caspase-12含量在1d、7d、14d、28d均高于对照组,差异有统计学意义(P<0.05),实验组右侧1d、7d、14d高于对照组,差异有统计学意义(P<0.05)。随着时间推移,实验组左侧CHOP和caspase-12含量逐渐升高,CHOP在7d、28d时与前一时间点比较差异均有统计学意义(P<0.05),caspase-12在14d、28d时升高较前一时间点差异有统计学意义(P<0.05)。实验组右侧CHOP和caspase-12的含量逐渐降低,CHOP在14d、28d时与前一时间点比较差异有统计学意义(P<0.05),caspase-12在7d、28d时降低较前一时间点差异有统计学意义(P<0.05)。结论偏侧咀嚼可引起大鼠髁突软骨发生病理性改建,内质网应激介导的凋亡反应是髁突软骨细胞重要的凋亡机制之一。

Objective To investigate the role of endoplasmic reticulum stress response(ERSR)in condylar chondrocyte apoptosis in rats with unilateral mastication,and to analyze the metabolic changes of ERSR-related protein factors.Methods A total of 96 male Sprague-Dawley rats aged 3 weeks were randomly divided into 4 experimental groups and 4 control groups.An animal model of left unilateral molar loss was established and they were sacrificed at 1d,7d,14d,and 28d after tooth extraction.The morphological changes of condylar cartilage were observed by HE staining.The changes in contents of CHOP and caspase-12 in the left and right condylar chondrocytes of each group were detected by RTPCR.Results HE staining showed that the normal structural stratification of the condylar cartilage in the experimental group was gradually blurred,with broken fiber,disorderly arranged cells,and reduced number of cells,and vacuolar degeneration were observed in the chondrocytes.The results of RT-PCR showed that the content of CHOP and caspase-12 on the left side of the experimental group was higher than that of the control group at 1d,7d,14d,and 28d,and the difference was statistically significant(P<0.05).The above indicators were higher in experimental groups than in control group at 1d,7d,and 14d,and the difference was statistically significant(P<0.05).The content of CHOP and caspase-12 on the left side of the experimental group were increased gradually with time.The difference of CHOP at 7d and 28d was statistically significant,as compared with those at at previous time points respectively(P<0.05).There were significant differences in caspase-12 at 14d and 28d,as compared with those at previous time points(P<0.05).The content of CHOP and caspase-12 on the right side of the experimental group were decreased gradually.Significant difference was found in CHOP at 14d and 28d,as compared with those at previous time points(P<0.05).Conclusion Unilateral mastication can cause pathological changes of condylar cartilage in rats.ERSR-mediated apoptosis is one of the important apoptotic mechanisms of condylar chondrocytes.