高频超声心动图评价小鼠病毒性心肌炎模型的心功能改变

摘要

Objective　To assess the cardiac function of viral myocarditis model in mice by high frequency echocardiography , and the relationship among the cardiac function , pathologic scores, and virus RNA in myocardium.Methods　Thirty VMC mice and 10 normal mice were served as viral and control groups. Echocardiography was performed on the 7th day after virus injection to get the cardiac function indexes(FS, Vp, Vi). Histological cross sections of heart were stained with HE and scored for myocarditis lesions, and myocarditis mice were divided to mild group and severe group. Viral RNA was detected in heart sections by in situ hybridization and quantified by digital image analysis.Results　Cardiac function indexes were decreased a bit in mild myocarditis(n=20) but no significance compared with those in normal control group, while the indexes were significantly decreased (P<0.05) in severe myocarditis (n=7) when compared with those in mild myocarditis and control group. Cardiac function indexes(FS, Vp, Vi) negatively correlated with pathologic scores（r=-0.56、-0.84、-0.58，P<0.01）. The positive signal of viral RNA in severe group was more than in mild group (P<0.05),but there was no correlation between cardiac function and viral RNA in myocardium.Conclusions　High frequency echocardiography was credible to detect the cardiac function in myocarditis mice. The depression of cardiac function correlates with the severity of pathology.%目的　用高频超声心动图方法研究小鼠轻、重症病毒性心肌炎（VMC）的心功能改变及其与病理、心肌病毒含量的关系。方法　VMC模型组30只小鼠，正常对照组10只。VMC模型组注射病毒后第7 d，存活的小鼠行超声心动图检查，测定左室短轴缩短分数（FS）、主动脉血流峰值流速（Vp）、主动脉流速积分（Vi），根据心脏病理评分分为轻症组和重症组，心脏中段石蜡切片进行原位杂交检测病毒RNA。结果　与正常组相比，轻症心肌炎组（20只）左室收缩功能稍减低，但无统计学差异；重症组（7只）收缩功能明显减低（P<0.05)；重症组病毒RNA阳性信号面积定量较轻症组为大（P<0.05)；心功能（FS、Vp、Vi）与病理积分呈负相关（r分别为-0.56、-0.84 和-0.58，均P<0.01）；心功能与心肌病毒RNA含量无相关性（P>0.05)。结论　超声心动图为研究小鼠VMC模型心功能改变提供了简便可靠的方法，心功能减退程度取决于心肌坏死程度。