【摘要】 目的观察Wistar大鼠肺组织中卡氏肺孢子虫生长发育的超微结构。方法45只雌性Wistar大鼠随机分为2组,实验组(35只)每周2次经皮下注射地塞米松(1mg/次),对照组(10只)不作处理同步饲养。分别于首次注射地塞米松后第1～10周内,每周取两组鼠肺组织,电镜下观察卡氏肺孢子虫的感染情况及其生长发育的超微结构。结果电镜下观察,卡氏肺孢子虫虫体主要寄生于Wistar大鼠肺泡腔内,也见于肺泡膈、肺巨噬细胞和中性粒细胞,虫体表面有管状突起,内含细胞核、线粒体、空泡、粗面内质网和丰富的核糖体。许多卡氏肺孢子虫滋养体附着于肺Ⅰ型上皮细胞,偶见附着于肺Ⅱ型上皮细胞,有的伸出1或多个较宽大的伪足,部分细胞质内发现核相关细胞器和纺锤微管。囊前期有早、中、晚3种类型,在其内发现代表减数分裂的联会复合体。包囊壁上有一增厚处,内有一孔隙。结论卡氏肺孢子虫生活史由滋养体、囊前期和包囊等构成,包囊壁增厚处孔隙的存在提示为囊内小体逸出的一种模式。更多还原

【Abstract】 Objective To study the life cycle and morphology of Pneumocystis carinii by ultrastructural observation.Methods Wistar rat model of P.carinii infection was established by subcutaneous injection with dexamethasone.Lung tissue of the infected rats was used for the transmission electron microscopical study.Results The organisms were mainly present in the lung alveolar cavity,and also in the alveolar septem,pulmonary macrophages and neutrophils.More trophozoites of P.carinii attached to the type Ⅰ alveolar epithelial cells,and rarely to the type Ⅱ alveolar epithelial cells.Most of these trophozoites showed pseudopodial evaginations on their pellicles.The nucleus-associated organelle and spindle microtubules were observed in some trophozoites.The precyst phase was in three forms:early,intermediate and late form.Synaptonemal complexes indicating meiotic nuclear divisions and a clump of mitochondria were also observed in the precyst.The pellicle of the cyst has a thickened portion with a pore.There were nucleus with nucleolus,mitochondrion,vesicles,endoplasmic reticulum and numerous ribosomes in the organisms,and tubular expansions on its surface.Conclusion The life cycle of P.carinii consists of trophozoite,precyst and cyst stages.The presence of a single pore in the cyst wall reveals that pore formation may be a mode of excystation for intracystic bodies of P.carinii.更多还原