ABSTRACT
For exploring the histopathological changes of intestinal tissues and the mechanism of porcine deltacoronavirus(PDCo V) replication and leading to inflammatory lesions of piglets intestine which induced by PDCo V infection, 10-day-old piglets were infected by PDCo V strain TJ1 which isolated from Tianjin through oral route in this study. The piglets were necropsied at 4 days post-infection. Through histopathological observation, the main lesions of jejunum, ileum, colon and cecum were investigated. The diffuse inflammatory cell infiltration was found in mesenchyme, lamina propria and submucosa of intestinal mucosa, and the mucosal villi atrophy occurred in response to local tissues. The m RNA expression level of PDCo V M gene, innate immune genes including IFN-a, IFN-beta, DDX58 and STAT2 as well as the inflammatory cytoines including TNF-a and IL-6 in intestinal tissues were examined. The results showed that PDCo V replication was achieved by inhibiting host cell innate immune response, and the occurrence of inflammatory lesions in jejunum, ileum and colon were promoted through the enhancement of TNF-a and IL-6 expression. This study can provide a theoretical basis for the pathogenic mechanism study of porcine deltacoronavirus.