【Animal Modeling】-Guinea Pig Pulmonary Tuberculosis Model

  (1) Breeding method Using female Hartley guinea pigs, in the middle of the logarithmic growth phase, dilute Mycobacterium tuberculosis with sterile double-distilled water to the required inoculation concentration, and add 5 ml of it to the nebulizer compartment Distilled water for bacteria. , Terre Haute, Indiana. Give each guinea pig 20-50 bacteria. After the model guinea pig is infected with Mycobacterium tuberculosis, the body reacts to the Mycobacterium tuberculosis and causes tissue damage. In the early stages of infection, small, discontinuous epithelial macrophages containing eosinophil granules appear in the lung parenchyma near the trachea and blood. Blood vessels. Inflammation caused by dense aggregates of granulocytes; then the diameter of the lesion increases, and granulomatous lymphadenitis gradually forms; later it develops into a typical granuloma; in the late stage of granuloma, multiple granulomas. A dense inflammation zone is formed, the alveolar structure disappears, the necrotic center forms a typical calcification, and pulmonary fibrosis appears in the middle and late stages of infection. Guinea pigs can be killed 100 to 140 days after infection. ..

  (2) Different infection routes and inoculation doses of the model characteristics lead to different severity of animal infections and different survival rates. Guinea pigs can survive 4-8 weeks by intraperitoneal injection of 2 x 1,000,000 Mycobacterium tuberculosis. This model uses a small amount of Mycobacterium tuberculosis. Tuberculosis aerosol infects guinea pigs. , Cause chronic tuberculosis infection in guinea pigs, and produce the same symptoms as human tuberculosis infection. Three months before being infected with tuberculosis, guinea pigs develop progressive lung disease due to the cell-mediated immune response and delayed internal allergies to tuberculosis, and then enter the chronic infection stage such as granuloma and pulmonary fibrosis. Chronic tuberculosis has a long life span.

  (3) Comparative medicine Guinea pigs are sensitive to Mycobacterium tuberculosis. In guinea pigs, only 20-50 bacterial aerosol infections can reproduce the disease model of Mycobacterium tuberculosis. The transmission route is the same as that of natural person infection, and chronic infection will occur. Because the symptoms and cases of pathological changes are similar to those of human infection with Mycobacterium tuberculosis, guinea pigs are useful in the research of Mycobacterium tuberculosis pathogens, disease progression, immunological research and vaccine evaluation. However, controlling the number of bacteria infected by aerosols is not easy, difficult to operate, and requires related equipment. The only shortcoming of guinea pig as an animal model is the lack of immune reagents, which makes it difficult to characterize and quantify the cytokines and cell subtypes related to the immune response.