Study On Histopathologic Changes And Cell Apoptosis Of Muscovy Duck Infected With Muscovy Duck Reovirus

10-day old Muscovy ducks were infected with Muscovy Duck Reovirus. Histo-pathological changes, apoptosis and the expression of death factor Fas-L of infected tissues were studied at 6h, 12h, 24h, 48h, 60h, 72h, 84h, 108h, 144h, 204h, 13d and 16d after infection, using hispathological methods, electron microscope, in-situ end labeling technique and immunohistochemistry methods.Grossly, the characteristic pathologic changes of infected Muscovy ducks were gray-white necrotic spots on the surface and in the parenchyma of liver, spleen and kidney.The histopathological changes showed that various degrees of degeneration, necrosis, hyperemia, and infiltration by lymphocytes and macrophages in the foci and perivascular regions occured in many organs; The lymphocytes of immune-organs such as spleen, bursa of fabricius and thymus appeared necroses, and decreased in number.The characteristic changes were that hepatocytes happened various extents of fatty degenertion, vacuole degeneration and focal necrosis, infiltration of lymphocytes and macophages from periphery to central areas. Some lymphocytes of spleen necrosed and decreased in number.Ultrastructural study revealed that the characteristic changes of apoptosis, including cell shrinkage, chromatin condensation and margination, were observed in liver, spleen, kidney, lung, bursa of fabricius and cecum.The result of TUNEL staining revealed that a large number of positive cells pre -sent in many organ tissues, which showed that Muscovy duck reovirus can induced varying-degreed apoptosis in the liver, spleen, kidney, lung, thymus, cecum and bursa of fabricius.The result of immunohistochemical staining of death factor Fas-L showed that, the positive cells of Fas-L were observed in liver, kidney, lung, thymus, cecum and bursa of fabricius, and the changes of Fas-L expression were highly correlated with the level of apoptotic index. The mechanism of apoptosis induced by Muscovy duck reovirus is closely related with Fas-L.Based on the results above, we concluded that Muscovy duck reovirus can caused a great deal of gray-white necrosis in liver, spleen, kidney etc of infected Muscovy ducks. At the same time, the virus induced varying-degreed apoptosis in liver, spleen, kidney, lung, thymus, cecum and bursa of fabricius, and the pathway of Fas-FasL was one of mechanisms of apoptosis induced by virus.