高位脊髓损伤急性期大鼠心肌组织的动态变化

The dynamic change of myocardial tissue during the acute phase of high-level spinal cord injury in rats

目的 探讨高位脊髓损伤（SCI）急性期大鼠心肌组织的动态变化。方法 健康雄性SD大鼠30只,体重250~300g,随机分为假手术组（S组）、高位脊髓损伤后6小时（A组）、12小时（B组）、24小时（C组）、48小时（D组）五组（n=6）。用改良Allen’s打击法,建立高位SCI大鼠模型。分别于6、12、24和48小时时点测定血清肌钙蛋白I（c Tn I）、肌酸激酶（CK）和肌酸激酶同工酶（CK-MB）含量;Western blot检测心肌组织Ca SR蛋白变化;透射电镜下观察心肌细胞超微结构特征。结果 与S组比较,高位SCI后各组大鼠血清c Tn I、CK和CK-MB,心肌组织钙敏感受体蛋白质表达均显著升高（P〈0.05）,且c Tn I在6小时、CK-MB于12小时达峰值,CK及钙敏感受体蛋白质表达于24小时达高峰;C与D组相比上述各指标虽呈下降趋势,但仍显著高于S组（P〈0.05）。透射电镜下可见SCI后各组大鼠心肌损伤表象,其中以12小时出现肌丝灶样溶解、肌节大量崩溃、细胞膜破裂、线粒体大量移位和空泡变性,最具代表性,而24小时后趋向损伤减轻。结论 SCI大鼠血清c Tn I、CK和CK-MB,心肌组织钙敏感受体蛋白质表达均呈动态变化,SCI后48h仍未回复正常,心肌细胞超微结构特征证实高位SCI急性期发生大鼠心肌损伤,且24小时后趋向减轻。

Objective To investgate the dynamic change of myocardial tissue during the acute phase of high-level spinal cord injury in rats. Methods 30 male SD rats were randomly divided into five groups with six rats each：sham group （S group）,spinal cord injury 6h,12h,24h,48h groups （A,B,C,D group）.The level of plasma creatine kinase （CK）,MB isoenzyme of creatine kinase（CK-MB）and cardiac troponin I （cTnI） were measured. The expression of Calcium sensing receptor （CaSR） protein was detected by western-blot. The change of ultrastructure in the myocardium of rats was observed by electron microscopy. Results In four injury groups, the values of CK,CK-MB, cTnI were much higher than that of sham group（P〈0.05） and cTnI content reached peak at 6 hours,CK-MB at 12 hours,CK and CaSR at 24 hours.Ultrastruetural examination of the myocardial tissue demonstrated that there were myocardial injury in all injury groups,and the most representative dissolution of myocardial fihrils and vacuolation mitochondria after injury in all injury groups was at 12 hours ,yet reducedfrom 24 hours. Conclusion Plsama CK,CK-MB,cTnI contents and expression of CaSR protein appeared dynamic changes in rats of SCI.The ultrastructural of myocardial ceils was demonstrated that there were myocardial injury during the acute phase of SCI,and could not recover at 48 hours.