外周血cTnI-mRNA对扩张型心肌病的诊断价值

Distribution of peripheral blood myocardial troponin I mRNA and the value for diagnosis of dilated cardiomyopathy

目的:探讨外周血心肌肌钙蛋白I(cTnI)-mRNA在外周血的分布规律及其对扩张型心肌病的诊断价值。方法:32例扩张型心肌病患者,应用逆转录聚合酶链反应(RT-PCR)法,分别从外周全血及单个核细胞扩增cTnI-mRNA,同时对照研究外周血心肌酶谱(肌酸激酶及其同工酶、天门冬氨酸氨基转移酶、乳酸脱氢酶)活性及cTnI定性;1例心脏移植标本作病理学观察;20例正常献血标本设为对照组。结果:电镜观察,可见心肌线粒体肿胀、嵴断裂、严重空泡样变及细胞核异形变、染色质浓缩边聚;所有病例外周血单个核细胞扩增cTnI-mRNA均为阴性,外周全血扩增cTnI-mRNA 14例阳性;对照组单个核细胞及外周全血扩增均为阴性;32例中,酶学检测6例异常,外周血cTnI定性检测5例异常,RT-PCR法检测外周血cTnI-mRNA 14例阳性,RT-PCR的阳性率均高于酶学及cTnI定性检测(P<0.05和P<0.01)。结论:cTnI-mRNA存在于外周血浆;RT-PCR法扩增外周血cTnI-mRNA较酶学、cTnI定性检测对扩张型心肌病的诊断有更高的敏感性。

Objective：To explore the diagnostic significance of detection of myocardial troponin I mRNA（cTnI-mRNA） in peripheral blood for dilated cardiomyopathy. Methods：Reverse transcriptase polymerase chain reaction（RT-PCR） method was employed to detect cTnI-mRNA from the peripheral blood and nucleated cells of 32 patients with dilated cardiomyopathy. The serum levels of creatine kinase ,isocnzyme ,aspartate aminotranferase,lactate dehydrogenase and cTnI were studied at the same time. One blood sample from a patient receiving heart transplant was examined pathologically and twenty other blood samples from blood station were collected as control. Results： Swell cardiac myocytes, mitochondrial rupture, severe vacancy-like denatureation, nucleus abnormality and condensed chromatin borders were observed by electron microscopy. The RTPCR was all negative from nucleated cells, while fourteen positive RTPCR were detected from peripheral blood. In the control group, no positive results were found from either the nucleated cell or peripheral blood. Of the 32 patients ,positive enzymology was detected in six cases, positive cTnI was detected in five and fourteen had positive RT- PCR. The positive rate of RT-PCR was significantly higher than that of enzymology and cTnI detection （ P 〈 0.05 and P 〈 0.01 ）. Conclusions：cTnI-mRNA is located in the serum after myocardial injury occurred. RT-PCR method is more sensitive than enzynology and cTnI detection in the diagnosis of dilated cardiomyopathy.