RESUMEN
In order to explore the morphological changes of Bovine Kidney (MDBK) cells induced by foot-and-mouth disease virus (FMDV) L protease, we induced the expression of FMDV L protease in bovine kidney cells (MDBK) artificially. All work is carried out on the basis of a stable MDBK cell line inducibly expresses the Lab gene under the control of tetracycline. We use cell morphology, Hoechst 33258 staining, AO-EB staining, and DNA Ladder abstraction to research the morphological changes of MDBK cells. 24 hours after FMDV L protease were induced and expressed in MDBK cells, cells shown the diminish of cell size, nuclear enrichment and the appearance of transparency circle under the light microscope. Apoptosis characteristics of nuclear condensation, fragmentation, accompanied by apoptotic bodies formation (Hoechst 33258 staining). 36 hours after the expression, nuclear staining of early lesions showed bright green plaque or debris-like dense, and advanced lesions showed Orange and dense plaques (AO-EB staining). 48 hours after the expression, DNA gel electrophoresis showed visible DNA ladder. Results indicate that FMDV L protease can induce apoptosis of MDBK and apoptosis plays an important role in the cytopathogenicity effect of FMDV.