Studies On Pathogenic Character Of New Type Duck Hepatitis Virus And Apoptosis Of Liver And Pancreas In Infected Ducklings

9-day old ducklings were inoculated with New Type Duck Hepatitis Virus. Using pathological methods, electron microscope and immunohistochemistry methods, at 12h, 24h, 48h, 72h, 168h and 14d post inoculation(PI), 13 of serum biochemical indexes, the NO of the serum, liver and brain, the TNF, IL-2 of the serum, dynamic distribution of virus, pathological changes, apoptosis, and apoptosis factor were studied.The result of 13 of serum biochemical indexes showed that: The activities of serum AST, ALT began to increased significantly at 24hPI. The levels of serum Glu, TP, ALB, GLB were dropped significantly. The activities of CHE increased significantly at 12hPI. The concentration of CRE decreased at 12h and increased at 24hPI. There were a lot of changes but have no roles in the activities of ALP, the concentration of UA, Ca and P. There were no changes in the activities of serum a-Amylase.The result of NO in the serum, liver and brain, the TNF,IL-2 in the serum showed that the levels of serum NO were increased significantly at 48h,72h and 96h post inoculation(PI). The activities of liver NO began to increased significantly at 24hPI. There were no changes in the activities of brain NO. The concentration of serum TNF and IL-2 increased significantly at 24h after inoculation, then dropped significantly at 96hPI.Histopathological examination revealed the hemorrhagic and necrotic inflammation of the liver at 24h post inoculation. At 48h to 96h post inoculation, proliferative inflammation was observed. There was limitation coagulation necrosis and Councilman's bodies in pancreas at 24h post inoculation and it became the most extensive and serious at 48h post inoculation, between 72h to 168h post inoculation, there was heterophil infiltrating into pancreas and became more serious, the limitation coagulation necrosis and Councilman's bodies became lighten, at 14d post inoculation, only heterophil infiltration was observed. All the time, the nonsuppurative encephalitis, necrotic splenitis was observed in the brain, spleen respectively, and it was observed heterophil infiltrating into renal leaflet.The result of dynamic distribution of virus revealed the virus were present in liver, spleen between 24hPI to 96hPI, it also present in pancreas between 24hPI to 168hPI, and between 12hPI to 14dPI, the virus were present in thymus gland and bursa Fabriicii. There were no virus present in kidney, heart and brine. It was found that the virus was located in cytoplasm of positive cells.Ultrastructural study revealed the characteristic changes of apoptosis, including cell shrinkage, chromatin condensation, were observed in liver at 24hPI and pancreas at 48hPI.The result of TUNEL staining revealed the positively cells present in liver between 24hPI to 96hPI, and apoptotic index increased to the top at 24hPI. The positively cell present in pancreas between 24hPI to 168hPI, and apoptotic index increased to the top at 48hPI.The result of immunohistochemical staining of apoptotic factor caspase-3, Bcl-2, Bax and p53 in liver and pancreas showed that, the positively cells of caspase-3, Bcl-2, Bax were observed in liver between 24hPI to 168hPI, and in pancreas from 12hPI to 14dPI, and the changes of apoptotic indexwere paralleled positively with the changes of caspase-3, Bcl-2 and Bax expression. There were no positive cells of p53 in liver and pancreas between 12hPI to 14dPI, it revealed that there was no relation between apoptosis and p53 in liver and pancreas of infected duckling with New Type Duck Hepatitis Virus.Base on the study results, it showed that New Type Duck Hepatitis Virus invaded into the body of the ducklings, distributed in organs, caused lesion of the cells. At the same time, the virus induced apoptosis of hepacytes in liver and acinar cells in pancreas, and the changes of apoptotic factor was occurred.