病毒性心肌损伤时总RNA表达及cTnI基因的扩增分析

目的研究心肌型肌钙蛋白(cTnI)-mRNA在监测病毒性心肌损伤发生发展和预后中的价值。方法于BALB/c小鼠腹腔接种1×108TCID50柯萨奇病毒B3(CVB3)液诱发心肌损伤发生,分别在CVB3感染后第3、6、9、12、15、18和21天采集外周血后处死小鼠,留取鼠心脏作病理组织学检查,并以逆转录-聚合酶链反应(RT-PCR)分析心肌及外周血中cTnI基因的表达状态。结果CVB3感染后,鼠心肌组织及循环血中cTnI-mRNA均表达增加,且与心肌细胞肿胀、炎性细胞浸润、核固缩及碎裂、变性、坏死、钙化等组织学改变相关。cTnI-mRNA基因扩增,心肌组织全数阳性;外周血阳性率在对照组及感染后第3、6、9、12、15、18和21天分别为0、0、0、16.7%、40.0%、71.4%、83.3%和87.5%。结论病毒性心肌损伤时cTnI-mRNA上调表达并释放入血,循环血cTnI-mRNA为监测心肌损伤发生发展及预后的灵敏基因标志物。

Expression of total RNA and amplification of myocardial troponin Ⅰ gene during monitoring viral cardiomyocyte injury

BACKGROUND: To investigate the value of circulating cTnI-mRNA detection for monitoring myocardial injury development and prognosis. METHODS: Viral myocardial injury models in BALB/c mice were created by intraperitoneal inoculation with Coxsackievirus B3 (CVB3,1x108 TCID50) for inducing myocardial injury. The total RNAs were extracted and cTnI-mRNA in mice cardiac tissues and circulating blood were amplified by RT-PCR during mice myocardial injury. RESULTS: In virus infected mice, the mRNA abundance for cTnI was up-regulated in heart and circulating blood and associated with salient myocardial histopathologic features, including myocardial swelling, inflammatory cell infiltration, pyknosis, karyorrhexis, karyolysis, denaturalization, necrosis, and calcification. The cTnI-mRNA form infected mice heart and circulating cardiac myocytes were analyzed by RT-PCR, the amplified gene fragments were found in all heart tissues. The incidence of cTnI-mRNA was 0, 0, 0, 16.7%, 40.0%, 71.4%, 83.3% and 87.5% in the controls, the 3rd, 6th, 9th, 12th, 15th, 18th,and 21st day in circulating bloods from the infected mice, respectively. CONCLUSION: The present data suggest that cTnI-mRNA expression is up-regulated and released into blood on viral myocardial injury, and detection of circulating cTnI-mRNA is a sensitive genetic marker for monitoring myocardial injury development and prognosis.