Cathepsin-L在缺血心肌中的表达

目的检测cathepsin-L(CTSL)在大鼠早期缺血心肌中的表达变化,并探讨其法医学意义。方法建立大鼠早期心肌缺血模型,设置早期缺血组(early ischemic myocardium,EIM)、非缺血组(non-ischemic myocardium,NIM)、假手术组以及空白对照组,采用real-time PCR方法检测大鼠缺血后15min,30min,1h和2h CTSL mRNA的表达量,并进行组内和组间比较。收集心源性猝死者缺血心肌和机械性损伤致死者正常心肌样本,采用免疫组化染色方法观察心肌组织中CTSL蛋白表达。结果 EIM组CTSL mRNA表达量与NIM组、假手术组及空白组相比,在15min时无统计学意义(P>0.05),在30min、1h和2h时分别升高1.4、3.1和4.5倍(P<0.05);其余3组间差异无统计学意义(P>0.05)。观察10例冠脉狭窄程度Ⅲ～Ⅳ级的心源性猝死(SCD)者缺血心肌,CTSL表达增强。结论大鼠心肌缺血后早期即可检测到CTSL mRNA的升高,并在SCD冠脉狭窄死者缺血心肌中高表达,提示CTSL可作为心肌缺血与SCD的参考指标。

The expression of cathepsin-L in ischemia heart

Objective To investigate the expression changes of cathepsin-L(CTSL)in early ischemic myocardium(EIM)and non-ischemic myocardium(NIM)in rats.To evaluate the possibility of CTSL examination in the ischemia heart disease occurred in forensic medicine.Methods Early myocardial ischemia models of rats were established,and were divided into four groups as early ischemic myocardium,non-ischemic myocardium,sham operation and control group.Real-time polymerase chain reaction(RT-PCR) technique was applied for detecting the expression of cathepsin-L mRNA in EIM and NIM of rats at 15min,30min,1h and 2h post myocardial ischemia,and in sham operation(SO) group.Variation within groups and between groups of the results were analyzed with SPSS 13.0.Ischemic myocardium samples from sudden cardiac death and normal myocardium samples died from mechanical damage were collected for detecting the expression of CTSL by immunohistochemical(IHC) staining.Results Compared with NIM,SO and control groups,no significant differences of CTSL mRNA expression were observed in EIM in 15min(P>0.05).CTSL mRNA expression increased to 1.4 folds at 30min,3.1 folds at 1h,and 4.5 folds at 2h(P<0.05).No difference was observed among other three groups(P>0.05).Besides,CTSL augmented expression was detected with IHC in 10 ischemia hearts with Ⅲ~Ⅳ coronary stenosis after autopsies of SCD cases,while no positive staining was observed in 6 normal hearts from corpse of mechanical injury death.Conclusion CTSL could be detected at early ischemic myocardium of rats,and CTSL was intensely expressed in human ischemia hearts from SCD than mechanical injury death and may serves as a reference indicator of heart ischemia and SCD.