THE IN VITRO AND IN VIVO CYTOTOXICITYOF LIPOSOME-ENCAPSULATED DICHLOROMETHYLENE-DIPHOSPHONATE ON CHICKEN MACROPHAGES AND THE POTENTIAL OF USING MACROPHAGE-DEPLETED CHICKENS AS A MODEL FOR REOVIRUS INFECTION

摘要

The liposome-encapsulated dichloromethylene-diphosphonate (Lipo-MDPCl2) is known to be toxic to the cultured macrophages and has selective cytotoxic effects on macrophages in rats and mice, but has minimal adverse effects on the non-phagocytic cells following various administration routes. In this study, the cytotoxicity of Lipo-MDPCl2 on chicken macrophages was investigated. Similar to findings related to other mammals, the Lipo-MDPCl2 was toxic to the macrophages originating from the chicken peripheral blood mononuclear cells as indicated by the MTT (3-(4, 5-dimethylthiazole-2-yl) 2, 5-diphonyltetrazolium bromide) cleavage assays. After administered with Lipo-MDPCl_2, chicken spleens were rapidly and progressively reduced in sizes. This reductionwas more severely gross than with the experimental course. One day post-treatment, the histopathology showed that most of the macrophages around the peri-ellipsoid white pulp had undergone marked cellular necrosis and lysis, and more severe lesions appeared with the loss of lymphoid and reticuloendothelial tissues at 3 and 5 days post-treatment. White pulp which has been replaced by red pulp in the spleen were noticed at 3 and 5 days post-treatment. The flow cytometric assays further confirmed the depletion of the macrophages in the chicken spleens following the administration of MDPC12, when compared with those of the controls. Furthermore, the replication of the avian reovirus (ARV) in the spleens was significantly reduced in the macrophage-depletedchickens administered withLipo-MDPCl_2. Thus, depletion of the macrophages with Lipo-MDPCl2 followed by functional assesses in the macrophage-depleted chicken could be used as a model to confirm the involvement of the macrophages in ARV replication.