RESUMO
Objective To investigate the effects of different Leptospira strains on phagocytosis of peritoneal macrophages of guinea pigs,and explore the role of innate immune in the pathogenesis of leptospirosis. Methods Peritoneal macrophages of guinea pigs were infected in vitro by three different Leptospira strains,the virulent Leptospira interrogans serovar Lai type strain Lai,the avirulent L.interrogans serovar Lai type strain IPAV,and the nonpathogenic L.biflexa serovar Patoc type strain PatocⅠ,respectively,and heat inactivated Staphylococcus epidermidis was added 0.5,1.5,3 and 6 h after infection and incubated for 30 min.The effect of Leptospira on the phagocytosis of macrophage was evaluated by the inactivated Staphylococcus epidermidis phagocytosis rate and phagocytosis index.Phagocytosis and ultrastructure of peritoneal macrophages were observed by transmission electron microscopy 3 h after infection,and changes of cytoskeleton of the macrophages were observed by laser scanning confocal microscopy. Results The phagocytic rates and phagocytic indexes of strain Lai,strain IPAV and strain PatocⅠinfection groups were significantly lower than those of control group 3 h and 6 h after infection(P