机会致病原虫动物模型在实验教学中的应用

目的探讨机会性致病原虫在实验教学中的应用效果。方法选择卡氏肺孢子虫为机会致病原虫的代表虫种,Wistar大鼠为实验动物。实验课中给实验动物口服免疫抑制剂,学生按时观察实验动物的生理状态变化,并称体重后记录。至第3周取卡氏肺孢子虫肺组织匀浆,经右胸注入部分对照组和实验组大鼠体内。第6周解剖大鼠观察肺部病理变化,并取肺组织制片检查病原体。结果实验组大鼠口服免疫抑制剂醋酸地塞米松,5周后一般状态较差,有明显的脱毛,咳喘等现象;体重由原来的160～180g下降至120～140g;肺组织印片查到卡氏肺孢子虫。对照组大鼠在实验过程中体重逐渐增加,由原来的160～180g增至190～210g;一般情况良好,肺印片镜检未发现卡氏肺孢子虫。学生在实验报告中记录了观察和检查结果,对机会性致病原虫的致病特点有深刻认识。结论有效的实验操作是保证教学质量和培养创造性思维的关键。

Application of Opportunistic Protozoa Infected Animal Model in Teaching Human Parasitology Laboratory Course

Objective To investigate the use of opportunistic protozoa infected animal model in teaching human parasitology laboratory course. Methods Pneumocystis carinii was used as the representation of opportunistic protozoa and Wistar rat as host. The animals were orally administrated with immuno-suppressed drugs in experimental group. Students observed the body weight and physiological status of the rats at different time point. Two weeks after drug administration, rats of both experimental and control group were transtracheaUy inoculated with homogenate of P.carinii infected rat lung tissue. At sixth week, animals were dissected to examine the pulmonary pathological changes and the detection of P.carinii. Results In experimental group, rats administrated with dexamethasone, showed a bad physical condition and their body weights were droped from 160-180 g to 120-140 g after 5 weeks. P.carinii cysts were found in lung tissues smear of infected rats. In control group, rats showed a better physical condition and their body weights were increased from 160-180 g to 190-210 g. No cysts of P.carinii were found in lung tissue smear of rats. Students had gained a better understanding of the relationship between the immunity of infected host ad pathogenic protozoa. Conclusion Simple animal model of parasitic infection can provide partical experience for the students and enhance the teaching effectiveness.