【摘要】 目的:芽囊原虫是常见的人类肠道寄生原虫,但对其致病性仍不清楚。为比较在免疫功能正常与免疫功能低下状态下,芽囊原虫不同虫株对组织的致病性。方法:我们在半数SD实验大鼠饮水中加入地塞米松(dexamethasone,DEX)建立免疫功能低下模型,然后在除对照组外的实验组大鼠经口饲喂ST1、ST3和ST7不同虫株建立芽囊原虫感染,检测各组大鼠的病理学变化。结果:有空泡型芽囊原虫侵入肠道固有层,伴有粘膜糜烂脱落和炎症细胞浸润;在相同免疫功能状态下,分离自有症状患者的芽囊原虫虫株较分离自无症状带虫者的虫株造成更严重的病理变化;在免疫功能正常大鼠中,ST1和ST3感染造成的病理变化较ST7更为严重;芽囊原虫在免疫功能低下大鼠中造成的病理变化较在免疫功能正常大鼠中的更为严重。结论:分离自有症状患者的芽囊原虫虫株在免疫功能低下时致病性增强,分离自有症状患者的ST1和ST3虫株较其他虫株毒力更强。实验结果表明芽囊原虫致病性取决于虫株毒力和宿主的免疫功能状态。更多还原

【Abstract】 Objective: Blastocystis sp. is the most common enteric protozoan in human,but its pathogenesis is still unclear. To compare the infectious effects of various Blastocystis sp. on tissue damage in immunocompetent and immunocompromised status. Methods: We set up immunocompromised model by adding dexamethasone( DEX) to drinking water in half of experimental Sprague Dawley( SD) rats,and then orally challenged rats with different isolates of Blastocystis subtype 1( ST1),ST3 and ST7,and then examined the histological changes. Results: We found that the lamina propria was invaded by Blastocystis sp in the vacuolar form along with the mucus membrane slough and inflammatory cell infiltration,and the infections of strains isolated from symptomatic patients resulted in more severe histopathology changes than those from asymptomatic carriers in the same immune function status. In immunocompetent rats,ST1 and ST3 infection induced more severe histological changes than ST7 infection. The histopathological changes of immunocompromised rats were more severe than those of immunocompetent rats. Conclusion: the pathogenicity and augmentation of Blastocystis is enhanced when the strains were isolated from symptomatic patients and the host immunity was suppressed. ST1 and ST3 stains isolated from symptomatic patients have higher levels of virulence than other strains. The findings indicate the pathogenesis of Blastocystis sp depends on virulence of the strains and the immune status of the host.更多还原