Walzer P D, Powell R D, Yoneda K, Rutledge M E, Milder J E
Infect Immun. 1980 Mar;27(3):928-37. doi: 10.1128/iai.27.3.928-937.1980.
Pneumocystis carinii pneumonia was produced in two groups of rats by the administration of corticosteroids, a low-protein (8%) diet, and tetracycline in the drinking water. A third group not on corticosteroids or a low-protein diet served as controls. Members of the first group were sacrificed weekly for 8 weeks, and lungs were examined. A highly significant correlation was found between the histopathological assessment of the intensity of P. carinii infection and the number of cysts counted in enzyme-digested lungs. P. carinii progressively filled alveoli, and cyst counts increased from less than or equal to 10(4) to 10(9) cysts/g of lung at peak intensity of infection at 7 to 8 weeks. The second group of rats was placed on a regular diet and tapering doses of corticosteroids after week 4, and they were sacrificed at varying intervals for up to 21 weeks. P. carinii was not cleared from the lungs until after week 13 (more than 6 weeks after discontinuation of all steroids). Histologically, there was an increased prominence of alveolar macrophages and the progressive development of interstitial mononuclear cell infiltrate and fibrosis. Thus, P. carinii grows grows slowly in vivo and interacts with specific host cells. The resulting changes may be important in the pathogenesis of the infection and in the clearance of the organism from the lung after immunocompetence has been restored.
通过给两组大鼠施用皮质类固醇、低蛋白（8%）饮食以及在饮用水中添加四环素，诱发了卡氏肺孢子虫肺炎。第三组大鼠不使用皮质类固醇或低蛋白饮食，作为对照组。第一组大鼠每周处死一批，持续8周，并对肺部进行检查。在卡氏肺孢子虫感染强度的组织病理学评估与酶消化肺中计数的囊肿数量之间发现了高度显著的相关性。卡氏肺孢子虫逐渐填充肺泡，在感染高峰（7至8周）时，囊肿计数从小于或等于每克肺10⁴个增加到10⁹个。第二组大鼠在第4周后改为常规饮食，并逐渐减少皮质类固醇剂量，它们在不同时间点处死，最长至21周。直到第13周后（停用所有类固醇超过6周后），卡氏肺孢子虫才从肺部清除。组织学上，肺泡巨噬细胞的突出程度增加，间质单核细胞浸润和纤维化逐渐发展。因此，卡氏肺孢子虫在体内生长缓慢，并与特定宿主细胞相互作用。所产生的变化可能在感染的发病机制以及免疫能力恢复后病原体从肺部清除的过程中起重要作用。
