Pathological changes of extra-intestinal infection in newborn mice infected with human rotavirus

To understand the effect of spreading of rotavirus (RV) to the whole body in order to provide some references to the pathogenesis, clinical diagnosis and treatment of extra-intestinal RV infection, RVs were inoculated via oral route and injected to the newborn mice intra-abdominally. The pathological changes of the newborn mouse model infected with human RV were observed by means of light and transmission electron microscopy, and the direct evidence of RV infection could be demonstrated by in situ hybridization and PCR assay. It was found that pathological changes could be demonstrated in villi of small intestine, lamina propria of stomach and myocardial cells in case of mice orally administrated with RV, while in case of mice intra-abdominally injected with RV, pathological changes could be demonstrated also in liver and kidneys in addition to the changes mentioned above. Under electron microscopy, the pathological changes in liver cells included marked swelling and agglutination of mitochondria, pyknosis or collapse of cell nucleus, dilatation of the rough endoplasmic reticulum and the presence of large amount of fat droplets and vacuoles in liver cells. In addition, obvious dilatation of cholangioles and shedding of microvilli in cholangioles could be demonstrated . The positive results to detect RV by in situ hybridization appeared in the intestinal villi of mice taken orally, but they appeared in the intesitnal villi and the proximal convoluted tubules in kidneys of mice injected with RV abdominally. Meanwhile, the positive results revealed by indirect in situ PCR appeared in the intestinal villi, glandular cells of intestine, epithelial cells of the proximal convoluted tubules and collecting tubes in kidneys of mice token RV orally, but they appeared in the intestinal villi as well as in liver, kidneys, heart and pancreas of mice injected with RV abdominally. It is concluded that the human RV infection can cause damages in a lot of internal organs of the infected mice, once RVs spread into the whole body.