大鼠肺孢子虫肺炎动物模型的实验研究

目的建立肺孢子虫肺炎(PCP)的大鼠实验动物模型。方法将34只雌性清洁级SD大鼠随机分成实验组和对照组,每组17只。实验组采取每周2次每次每只皮下注射地塞米松1mg诱导的方法建立PCP动物模型;对照组则注射与地塞米松等体积的灭菌生理盐水。所有大鼠的饮水中加入1g/L盐酸四环素预防继发性细菌感染。12周后解剖全部大鼠,并分别制作肺组织印片,姬氏染色,检查肺孢子虫包囊。同时制作肺组织病理切片,HE染色,观察肺组织的病理学变化。结果用地塞米松诱导大鼠5周,肺组织印片均查见肺孢子虫包囊,肺组织也出现典型的病理学改变。连续诱导12周,均未见实验鼠死亡。实验组大鼠体重下降明显,与对照组比较,差异有非常显著性(P<0.01)。结论应用皮下注射地塞米松免疫抑制诱导的方法可成功建立PCP的大鼠动物模型。

Experimental study on animal model of Pneumocystis carinii pneumonia in rats

Objective To develop an experimental model of Pneumocystis carinii pneumonia (PCP) in rats . Methods Thirty-four female SD rats were divided into experimental and control groups randomly,and each seventeen. The animals in the experimental group were immunosuppressed by a quantitative subcutaneous injection of dexamethasone with a dosage of 1 mg per time per rat, twice a week. Those in the control group underwent the same way of injection with physiological saline simultaneously. Meanwhile, for prevention from the potential infections caused by other microbiological pathogens,all animals in both groups were allowed to drink tap water freely,which was dissolved with tetracycline with the concentration of 1 g/L.Lung smears made from the lung tissue of each rat were stained by Giemsa's stain, and examined microscopically for identifying the cysts of Pneumocystis carinii (PC). Histopathological sections of the lung tissues of the infected animals were stained by HE stain for the observation of histopathological changes. Results After being induced by dexamethasome, multiple PC cysts were found in the lung smears. Obvious histopathological changes of the lung tissues of infected animals were observed. The mortality of the experimental SD rats was zero after being induced 12 weeks by dexamethasone. Compared with those in the control group, the body weights of the induced animals in the experimental group declined significantly (P<0.01). Conclusion The method with which quantitative dosages of dexamethasone are subcutaneously injected with a dosage of 1 mg per time per rat twice a week is suitable for establishing an animal model of PCP.