轮状病毒感染致乳鼠肠外损害的实验研究

Extraintestinal lesions caused by rotavirus:An experimental study on suckling mice

目的探讨轮状病毒(rotavirus,RV)感染引起肠外脏器损害情况及其发病机制。方法用MA104细胞培养猴RVSA-11经口感染生后7d昆明小鼠乳鼠,实验组每只经口接种0.1ml培养物冻融液(3.75×107pfu/ml),对照组经口接种0.1ml正常对照细胞冻融液。接种后3d处死乳鼠,光镜下观察脑、肺、心、肝、胰和肾组织病理改变,电镜下观察心肌细胞超微结构改变;以免疫荧光方法检测各器官RV抗原分布情况;以Phalloidin-TRITC对丝状肌动蛋白染色并经软件(Imageproplus5.1,IPP5.1)测量分析以观察心肌组织丝状肌动蛋白含量有无改变;以原位凋亡细胞检测方法检测肝细胞和心肌细胞凋亡情况;以巢式RT-PCR方法检测各器官内RVRNA分布情况。结果在光镜下脑、肺、胰和肾组织未见明显病变,但可见心肌间质水肿,心肌细胞浊肿,肝细胞空泡变性;电镜下心肌细胞肌丝溶解,线粒体内室扩张,滑面内质网扩张,核周间隙增宽;Phalloidin-TRITC染色未见心肌组织丝状肌动蛋白含量改变;除脑组织外其他器官内见到RV抗原分布,而各器官内均有RV-RNA分布;肝细胞凋亡增加,而心肌细胞未见凋亡。结论RV可播散到肠外脏器并引起病理损害,但总体上程度较轻。病毒感染导致丝状肌动蛋白解聚及细胞骨架损害、诱导细胞凋亡不仅是肠黏膜损伤的机制,同时也是肠外损害的机制。

Objective To study the extraintestinal lesions induced by rotavirus （RV） infection and explore the pathogenesis. Methods Simian rotavirus SAll was cultured in MA-104 cells. After inoculation, the pathological changes in brain, lung, heart, liver, pancreas and kidney tissues were observed, the RV antigens detected, and the apoptotic cells observed. Besides, we stained the filamentous actin （F-actin） with Phalloidine-TRITC, and then quantified the F-actin amount. Results Several pathological changes, inclusive of myocardial interstitial edema, granular degeneration in cardiacytes, hepatic congestion, and hepatocellular vacuolar degeneration, were found, but not found in the brain, lung, and pancreas tissues. Meanwhile, several ultrastructural changes, inclusive of dissolved myocardial F-actin, extended smooth endoplasmic reticulum, swollen mitochondria, and widened perinuclear space, were found. No difference was found in the quantity of myocardial F-actin. Apoptosis was found in liver cells, but not in myocardial cells. RV RNA was detected in tissues such as brain, lung, heart, liver and pancreas tissues. Conclusion All the results suggest that RV may spread from the intestine to various extraintestinal organs and hence induce injury. Filamentous actin depolymerization, cytoskeleton damage and apoptosis induced by RV infection are the important mechanism not only in intestinal damages, but also in extraintestinal lesions.