Study On MDBK And L929 Cells Apoptosis Induced By Bovine Ephemeral Fever Virus Infection

Bovine ephemeral fever is a bovine infectious disease caused by bovine ephemeral fever virus(BEFV),and it leads to great harm and economic losses worldwide.So far,few studies have been developed on BEFV infection and pathogenicity,and its pathogenesis remains unclear.Research show that most of the animal virus can induce the host cell apoptosis after infection,and it may futher lead to animal epidemics.In this paper,the ability of BEFV infection to induce the apoptosis of bovine kidney epithelial cells(MDBK)and mouse embryonic fibroblast(L929)was studied.The capability of BEFV infection in inhibiting the growth of MDBK cells and L929 cells,and the relationship between the growth inhibition and apoptosis were investigated.Morphological changes of BEFV-infected cells were observed using the inverted microscope,and the cells apoptosis was observed using the fluorescence microscope with AO/EB staining.The ultrastructure of apoptotic cells was observed by transmission electron microscopy,and the apoptosis rate was counted by flow cytometry.Results showed that the BEFV-induced growth inhibition to MDBK cells and L929 cells and the apoptosis of those two host cells are both in a time-and dose-dependent manner.The infected cells became smaller and round,and some cells began to fall off from the bottom wall.Dead cells presented typical morphological features of apoptosis,including the cells becoming smaller and round,forming the apoptotic bodies surrounded by membranes,etc.AO/EB staining confirmed the apoptosis of both cells.The apoptotic cells had darker nuclear material,mostly distributed surrounding the nuclear membrane,and showed uneven bright green fluorescence.The number of apoptotic cells increased as time went on,and the late ones showed orange-stained.Observations from electron microscope demonstrated the condensation of the nuclear and the aggregation of the chromatin around the nuclear membrane.