+Gz暴露诱发家兔颈部骨骼肌损伤的机制研究

Mechanism of cervical skeletal muscle injury induced by +Gz exposure in rabbits

目的探讨+Gz暴露诱发家兔颈部肌肉损伤的机制。方法雄性家兔20只,随机分为正常对照组、+Gz暴露组、+Gz暴露+颈部负重组、+Gz暴露+颈部负重+固定组,每组5只。使用动物离心机模拟+Gz暴露环境,+Gz暴露组、+Gz暴露+颈部负重组、+Gz暴露+颈部负重+固定组在+6 Gz环境下连续暴露4周。暴露前和暴露结束后,对各组家兔进行X线摄片;暴露前及暴露1、2、3和4周,采集各组家兔耳缘静脉血,采用ELISA检测血浆乳酸脱氢酶(LDH)、肌酸激酶(CK)、活性氧(ROS)水平;暴露结束后取家兔颈部斜方肌,采用HE染色观察肌肉形态变化,TUNEL检测细胞凋亡情况,Western blotting检测凋亡相关蛋白Bax、Bcl-2的表达情况;取家兔颈部斜方肌行蛋白组学检测,挑选差异表达蛋白并进行GO功能聚类分析。结果暴露前后各组家兔颈椎形态无明显差异;与正常对照组比较,+Gz暴露组、+Gz暴露+颈部负重组、+Gz暴露+颈部负重+固定组血浆LDH、CK、ROS水平升高(P<0.05);与正常对照组比较,+Gz暴露组凋亡相关蛋白Bax/Bcl-2比值明显增高(P<0.05),TUNEL阳性细胞数明显增多(P<0.05)。与+Gz暴露组比较,+Gz暴露+颈部负重组凋亡相关蛋白Bax/Bcl-2比值明显增高(P<0.05),TUNEL阳性细胞数明显增多(P<0.05);与+Gz暴露+颈部负重组比较,+Gz暴露+颈部负重+固定组凋亡相关蛋白Bax/Bcl-2比值及TUNEL阳性细胞数有所下降,但差异无统计学意义(P>0.05);与正常对照组比较,+Gz暴露组中共600个蛋白发生显著变化,对差异蛋白进行GO功能聚类分析发现其显著富集于线粒体功能相关蛋白。结论+Gz环境暴露可引起家兔颈部肌肉损伤,导致细胞凋亡,而固定家兔颈部受力环节可缓解肌肉损伤症状;+Gz环境暴露导致的细胞凋亡可能与线粒体功能相关。

Objective To study the mechanism of+Gz environment exposure induced neck muscle injury in rabbits.Methods A total of 20 male rabbits were randomized into the negative control group,+Gz exposure group,+Gz exposure plus neck loading group,and+Gz exposure plus neck loading plus fixation group (5 in each group).The animal centrifuge was used to simulate the+Gz exposure environment.Rabbits in the+Gz exposure group,+Gz exposure plus neck loading group,and+Gz exposure plus neck loading plus fixation group were exposed for 4 weeks in a+6 Gz environment.Before and after the experiment,the rabbits in each group were photographed by X-ray.At the time of 0-,1-,2-,3-and 4-week exposure,ear vein blood was collected from rabbits in each group,and ELISA was performed to detected plasma leveles of lactate dehydrogenase (LDH),creatine kinase (CK) and reactive oxygen species (ROS).After exposure,the trapezius muscle of rabbits was taken for HE staining to detect the muscle morphology.The apoptosis level was detected by TUNEL in the paraffin section of the rabbit trapezius muscle.The expressions of apoptosisrelated proteins Bax and Bcl-2 in the trapezius muscle of rabbits were detected by Western blotting.The rabbit?s neck trapezius muscle was taken to conduct proteomics testing,select differentially expressed proteins,and perform protein function cluster analysis.Results There was no significant difference in the morphology of the cervical vertebra in each group before and after+Gz exposure.Compared with negative control group,plasma levels of LDH,CK,and ROS in+Gz exposure group,+Gz exposure plus neck loading group,and+Gz exposure plus neck loading plus fixation group significantly increased (P<0.05).Compared with negative control group,the ratio of apoptosis protein Bax/Bcl-2 in+Gz exposure group significantly increased (P<0.05),the number of positive apoptosis cells detected by TUNEL significantly increased (P<0.05).Compared with+Gz exposure group,the+Gz exposure plus neck loading group showed an increased Bax/Bcl-2 ratio (P<0.05) and more TUNEL positive cells (P<0.05).Compared with+Gz exposure plus neck loading group,the ratio of apoptosis protein Bax/Bcl-2 and the positive number of apoptosis were decreased in+Gz exposure plus neck loading plus fixation group,but there were no statistically significant differences (P>0.05).A total of 600 proteins were significantly altered in+Gz exposure group compared to negative control group,and GO functional clustering analysis of the differential proteins revealed significant enrichment of proteins associated with mitochondrial function.Conclusion Exposure to the+Gz environment can cause neck muscle injury and cell apoptosis in rabbits.The muscle injury symptoms can be improved by fixing the stress link of the rabbit neck.Cell apoptosis induced by+Gz exposure may be related to mitochondrial function.