病毒性心肌损伤时总RNA表达及cTnI基因的扩增分析

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

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。

Objective 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, 1 × 10^8 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 upregulated 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 RTPCR,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-regnlated 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.