卡氏肺孢子虫低死亡率SD大鼠动物模型的建立

目的建立低死亡率卡氏肺孢子虫肺炎(PCP)SD 大鼠动物模型. 方法将雌性SD大鼠随机分为实验组和对照组,实验组采用按体重定量皮下注射地塞米松免疫抑制的方法诱导建立PCP动物模型,对照组注射与地塞米松等体积的生理盐水.分别制作肺印片,经瑞-姬氏复合染色后,检查卡氏肺孢子虫包囊.制作肺组织病理切片,经HE染色后观察肺组织病理变化.制作感染大鼠肺组织超薄切片,透射电镜观察Pc包囊和滋养体.结果用地塞米松诱导后,实验组SD大鼠死亡率为0,肺印片阳性率为76.7%(23/30).肺组织出现典型的病理变化,并可观察到Pc包囊.实验组SD大鼠体重下降明显,与对照组体重比较具有极显著性差异(P<0.01).电镜下可观察到Pc包囊和滋养体的形态结构.结论采用按体重定量皮下注射地塞米松的方法可建立低死亡率PCP动物模型.

ESTABLISHMENT OF A SD RAT ANIMAL MODEL OF PNEUMOCYSTIS CARINII PNEUMONIA WITH A LOW MORTALITY

Objective To develop a SD rat animal model of Pneumocystis carinii pneumonia (PCP) with a low mortality. Methods Female SD rats were divided into experimental and control groups randomly. Animals in the experimental group were immunosuppressed by a quantitative subcutaneous injection of dexamethasone according to the animal's body weight twice a week. Those in the control group were undergone a subcutaneous injection of physiological saline simultaneously. The volume of the saline for per rat was similar to that of dexamethasone given to the experimental animal. Lung smear made from the lung tissue of each rat was stained by Wright-Giemsa's compound stain, and were examined microscopically for identifying the cysts of P. carinii (Pc). Histopathological sections of the lung tissues of the infected animals were stained by HE stain for the observation of histopathological changes. The extra thin sections of the lung tissues of them were made and observed under a transmission electron microscope (TEM). Results After being induced by dexamethasone, the mortality of the experimental SD rats were zero. Multiple Pc cysts were found in the lung smears and its positive rate was 76.7%(23/30). Obvious histopathological changes of the lung tissues of the infected animals were observed. Compared with those of the control group, the body weights of the induced animals in the experimental group declined remarkably (P<0.01). Ultrastructures of the cysts and trophozoites of Pc were observed. Conclusion The results showed that the method with which quantitative doses of dexamethasone were subcutaneously injected according to the animal's body weight was suitable for establishing an animal model of PCP with low mortality.