Rabbit Skin Pathological Model And Immunopathology Mechanism Of Tuberculosis

第一部分:Study on Rabbit Skin Model of Liquefaction induced by MycobaeteriumObjective In order to investigate the mechanism of tuberculosis pathology, in particular the mechanism of liquefaction,studies are conducted to establish a tuberculosis pathology model in rabbit skin using Mycobacterium bovis attenuated strain BCG,Mycobacterium tuerculosis avirulent strain H37Ra,and Mycobacterium smegmatis(M.smegmatis).Methods BCG,H37Ra,and M.smegmatis were injected separately in the flank of New Zealand White rabbits by intradermal route twice every one and half month. Fourteen days after the last injection,representing lesions were removed for further histological analysis.Results Apparent liquefaction and ulceration were produced in the skin of rabbits injected with high dose(5×106CFU/ml) of BCG,H37Ra,or M.smegmatis,and the ulceration happened around 10 days after first injection and 3 days after second immunization.The inflammation induced by BCG was stronger than the lesion induced by H37Ra,and the later was stronger than that induced by M.smegmatis.Moderate (5×104CFU/ml) and low doses(5×102CFU/ml) of H37Ra and M.smegmatis did not induce obvious lesions,while the moderate and low doses of BCG induced granuloma.Conclusion High dose of BCG,H37Ra and M.smegmatis could induce caseous necrosis and liquefaction in rabbit skin.These results demonstrate the usefulness of this model for further pathogenesis research. 第二部分:Study on expression of CD4,CD8,CD25 and CD68 molecular in tissues of human chronic fibrocavitary pulmonary tuberculosisObjective Characterize the distribution of CD4~+,CD8~+and CD25~+T cells and CD68~+ macrophage in human cavitary pulmonary tuberculosis in order to investigate the immunological mechanizism of pulmonary tuberculosis.Methods Surgical specimens from 10 patients of cavitary pulmonary tuberculosis were collected,and the expression of CD4,CD8,CD25 and CD68 in them were analyzed by immunohistochemical staining.Results In human cavitary pulmonary tuberculosis,caseous necrosis center is surrounded by layers of cells,consisting mononuclear cells,degenerating epithelioid and multinucleated giant cells,fibroblast,and lymphocyte etc.At the outside of the surrounding layers,CD4~+,CD8~+,and CD25~+ T cells and CD68~+ macrophage cells accumulated.Conclusion The active centers of the cross-talk between host and mycobacteria was the outside granuloma consisting of CD4~+,CD8~+,and CD25~+ T cell and CD68~+ macrophage cells rather than the caseous necrosis center or the surrounding cellular rim.