UNLABELLEDTo provide a reliable animal model for study of human CMV disease in gastrointestinal track, we tried to infect with murine cytomegalovirus (MCMV) in mice that were received allogenetic skin transplantation under immunosuppression. (1) Skin transplantation was performed between 18 donor C57BL/6 mice and 72 recipient BALB/c mice. (2) All recipient mice were then given Cyclosporine at 12 mg/kg daily for 2 weeks by intraperitoneal injection. Mice were randomly divided into 3 groups. Two experimental groups were received MCMV-infected mouse embryonic fibroblasts (MEF) at 10(4) PFU and 10(5) PFU respectively, and the control group received MEF only. We observed any possibly pathophysiological behavior changes and recorded the changes in body weight. The mice were sacrificed at 5d, 9d, 14d, 21d post infection and colon tissue was collected for analysis.

RESULTSMice infected with MCMV at 10(5) PFU group showed anorexia, lethargy and degression in locomotor activity. This group of mice showed significant decrease in body weight than that of other groups. Colon tissues were collected 14 days after infection. Histological examination revealed that the mucous layer became thinner in the proximal colon and increased number of lymphoid follicles in distal colon in infected animals. The changes in the mucosal structure was most prominent in the group 10(5) PFU MCMV. Viral DNA was present in the colon by in situ hybridization for IE1 gene, and viral gB transcript was positive by RT-PCR. One of the viral major proteins, pp65, was widely distributed in the colon by immunohistochemistry. These data demonstrated that MCMV established infection in colon of the mice after allogenetic skin transplantation. Electron microscopy showed that there were herpes virus particles in the colon tissue.

CONCLUSIONInfection with MCMV in mouse after allogenetic skin transplantation by nasal cavity inoculation resulted in the pathological changes in colon tissue similar to that of inflammation in human colon. The small animal model of colon inflammation may provide a platform for further study of pathogenesis as well as medical intervention of HCMV involved inflammation of human bowel.