CVB_(3m)重复感染心肌致心室重构的实验研究

Study of ventricular remodelling after repetitive infection of CVB_(3m)

目的探讨CVB3m重复感染致病毒性心肌炎心肌结构的改变。方法用梯度倍增法连续4次经腹腔注射CVB3m病毒液感染昆明鼠,分别于末次感染后10、30、60d处死动物,电镜下观察心肌细胞超微结构的改变,HE染色观察心肌病变程度和分布,VG染色观察心肌纤维增生情况。结果⑴电镜下显示末次感染后10d肌丝走行紊乱,线粒体大部分肿胀,少数嵴溶解消失,肌浆网扩张,溶酶体糖原颗粒增多。30d时肌丝紊乱程度减轻,糖原减少,核周有轻度的低电子密度区,线粒体嵴仍有断裂或絮状变,基质密度降低。60d时心肌间质中血管周围有大量纤维素的沉积,胶原纤维合成增多。⑵HE染色显示末次感染后10d心肌损伤严重,30d时仍可见小灶坏死,60d时未检出心肌损伤。⑶VG染色表明末次感染后10d心肌即出现较弱的胶原染色,30d时胶原明显可见,60d时心肌组织的胶原显著增加,心肌组织血管周围胶原面积(PCVA)和心肌胶原容积分数(CVF)均显著增加。结论CVB3m重复感染可导致急性期严重的心肌坏死,慢性期心肌胶原沉积和心肌纤维化。

Objective To investigate the structure changes of heart in viral myocarditis caused by repetitive infection of CVB_(3m).Method 4-week-old mice were infected 4 times intraperitoneally with a time-dependent dose and killed at the 10, 30 and 60 day after the final infection respectively to be examined the structure changes of heart and collagen hyperplasia by electric scope and HE,VG stain under light scope. Results ⑴10 days after the final infection, there was disorderly myocardium, and swollen mitochondria with ridges dissolved and disappeared, dilated sarcoplasmic reticulum and increased lysosome; At the 30th day, there was much regular myocardium and less glycogen, yet, some damaged mitochondria existed. One month later, there was much cellulose sediment around vessels in interstitium and more collagen in myocardium.⑵Heart damage appeared very serious at the tenth day, even there were small necrotic foci at the day of 30, but no injury of heart could be seen 2 months later after final infection.⑶Collagen appeared at the tenth day and there were much more collagen in heart and increased PCVA, CVF index at the sixtieth day. Conclusion It strongly indicated that repetitive infection of CVB_(3m)could lead to serious heart injury in acute period and myocardium fibrosis in chronic period.