柯萨奇B病毒性心肌炎小鼠急性期心肌组织微小RNA1初始体和连接蛋白43的表达

目的观察柯萨奇B病毒性心肌炎小鼠急性期心肌组织微小RNA1初始体(pri-miRNA-1)和连接蛋白43(Cx43)表达变化,探讨病毒性心肌炎(VMC)室性心律失常发生机制。方法40只4周龄雄性Balb/c小鼠随机分为VMC组(n=20)和对照组(n=20)。VMC组小鼠腹腔注射柯萨奇病毒B3(CVB3)Nancy株悬液0.1ml,对照组小鼠腹腔注射不含病毒的RPMI1640培养基0.1ml,分别于接种病毒后第14天无痛苦处死全部小鼠并留取心脏。逆转录-聚合酶链反应(RT-PCR)检测心室肌组织pri-miRNA-1的表达,免疫组织化学法检测Cx43蛋白水平表达,并进行半定量分析。结果①VMC组小鼠心室肌组织pri-miRNA-1表达量明显高于对照组(0.82±0.04vs0.63±0.07,P(0.01);②VMC组小鼠心室肌组织炎症病灶中变性、坏死周围心肌细胞Cx43表达明显减弱,甚至阴性,分布不规则,Cx43蛋白表达明显低于对照组(0.27±0.01vs0.42±0.02,P(0.01);③VMC组小鼠心室肌组织的pri-miRNA-1表达量与Cx43蛋白水平呈显著负相关(r=-0.868,P(0.01)。结论CVB心肌炎小鼠急性期心肌组织pri-miRNA-1表达上调,Cx43蛋白表达下降,miRNA-1可能通过抑制Cx43表达促进室性心律失常的发生。

Expressions of myocardial pri-miRNA-1 and connexin43 in a murine model of acute viral myocarditis induced by Coxsac- kievirus B

Objective To investigate the expressions of myocardial pri- miRNA-1 and eonnexin43 in murine model of acute viral myoearditis induced by eoxsackievirusB3 （ CVB3 ） and the relationship between the change and ventricular arrhythmia in viral myocarditis. Methods Forty four-week-old male Balb/c mice were divided randomly into viral myocarditis group （n = 20） and control group（ n = 20）. Myoearditis model was created by injecting intraperito- neally 0. 1 ml CVB3 Nancy solution. Control mice were injected with 0.1 ml RPMI 1640 excluding virus. Two group mice were sacrificed on day 14 respectively after injecting CVB3. Ventricular myocardium was obtained. The expression of pri-miRNA-1 were measured by RT-PCR. Connexin43 was determined by immunohistochemistry. Results Compared with control group, the expressions of pri-miRNA-1 was significantly increased in viral myocarditis group （ 0.82 ± 0.04 vs 0.63 ± 0.07, P 〈 0.01 ） ; Connexin43 were decreased remarkably in viral myoearditis （0.27 ±0.01 vs 0. 42 ±0.02, P 〈 0.01 ）. The decreased expression of eonnexin43 was located in the degenerative part of the myocardium; Myocardial pri-miRNA-1 was negatively correlated with connexin43 protein （ r = - 0. 868, P 〈 0.01 ）. Conclusion The expression of pri-miRNA-1 was increased markedly in acute viral myocarditis while Cx43 was decreased remarkably. MiRNA-1 might control arrhythmia by inhibiting the expression of connexin 43.