弓形虫PRU株慢性感染小鼠脑部包囊的时空分布特征

目的观察实验小鼠脑内包囊的时空分布特点,为探讨弓形虫感染引起的情志和行为改变提供病理基础。方法弓形虫PRU株经口感染小鼠,经HE染色和免疫组化检测,在显微镜下计算前额、海马、丘脑、小脑和杏仁核部位的包囊个数,然后随机选取上述部位的5个视野拍照,计算包囊的平均密度,并用方差分析比较不同脑组织包囊密度有无统计学差异。结果弓形虫感染30和90d时,HE染色和免疫组化后显微镜观察发现,小鼠不同位置弓形虫包囊密度差异有统计学意义,其中,丘脑的包囊密度最大,其次是前额皮质、海马、杏仁核,小脑的包囊密度最小。丘脑的包囊密度显著高于其他4个脑区（P〈0.01）,小脑的包囊密度显著低于其它4个部位（P〈0.01）,而前额皮质、海马和杏仁核所含的包囊密度差异无统计学意义（P〉0.05）;弓形虫感染1个月时,杏仁核包囊密度明显低于感染3个月（F=18.314,P〈0.001）,但是小脑的包囊密度高于感染3个月（F=18.314,P〈0.001）。结论弓形虫包囊在慢性感染小鼠不同脑组织内的分布具有时空特异性,这可能是其临床表现的病理学基础。

Distribution and occurrence of prugniaud strain Toxoplasma gondii cysts in chronic infected mice

Objective To construct the chronic infection mouse model with prugniaud strain of Toxoplasma gondii; and to determine the distribution of cysts in the chronic infected mice. Methods Kunming mice were orally inoculated with cysts of prugniaud strains. The brains were examined for cysts by microscopic examination method. Infected mice were sacrificed at 1 and 3 months post infection, and the brain tissues were fixed by heart perfusion. The brain was embedded by paraffin, and the bradyzoites were visualized by HE staining and immunohistochemical method. The mean density of cysts in different part of the brains was analyzed using AVONA. Results After 30 and 90 days of Toxoplasma infection, most of the cysts were found in the thalamencephalon, prefrontal cortex, hippocampus and amygdale. The density of cyst was lower in cerebellum （P〈0.01）; while the density of cyst in the thalamencephalon was significantly higher than the other four regions （P〈0.01）. The density of cyst in cerebellum was significantly lower than the other four regions. However, the density of cyst in the other three regions was similar （P〈0.05）. In one month, the density of cyst in the amygdala of mice was significantly less than 3 months （F=18.574, P〈0.001）. but the density of cyst in the cerebellum was significantly higher than 3 months （F =18.314,P〈0.001）. Conclusion The distribution of cysts in chronic infected mice varied with time after infection. It may provide the pathological basis for the analysis of clinical manifestations of toxoplasmosis.