旋毛虫感染后肠易激综合征大鼠内脏敏感性及CD4^+/CD25^+T细胞的变化特征

Changes of visceral sensitivity and regular T cells after acute Trichinella infection in intestine of rats

[目的]观察旋毛虫感染后肠易激综合征(PI-IBS)不同造模时间点小鼠内脏敏感性的变化及调节T细胞的变化特征,探讨两者在PI-IBS发病机制中的作用及相关性。[方法]旋毛虫幼虫囊泡(350～400条)感染成年SD大鼠,分别于感染后2、8周后行结直肠扩张(CRD),记录腹壁肌电图(EMG),评价内脏感觉功能的变化。取大鼠外周血经流式细胞仪检测CD4+CD25+细胞比例,评价不同时间点调节T细胞比例变化特征。[结果]①CRD联合EMG腹外斜肌放电次数可以反映内脏感觉功能。②3组不同扩张压力(20、40、60mmHg)下,旋毛虫急性感染2、8周后(以相同年龄及相同饲养环境的大鼠为对照)腹壁肌电放电次数均显著增加,80mmHg组差异无统计学意义;提示旋毛虫急性感染后可导致内脏高敏感性,该效应可持续至少8周。③在急性感染后2周,外周血CD4+CD25+/CD4+明显减少,而至模型诱导成功8周后,血CD4+CD25+/CD4+比例趋于正常。[结论]旋毛虫PI-IBS早期存在内脏敏感性增高及调节性T细胞下调增高,晚期调节性T细胞趋于正常,而内脏高敏感性持续存在。

[Objective]To observe the changes of visceral sensitivity and the ratio of regulatory T cells at different time points after acute Trichinella infectious rats.To demonstrate the effect of visceral hyperalgesia and immuno-regulatory T cells in the pathogenesis of post-infectious irritable bowel syndrome individually and collectively.[Methods]Rats were infected by Trichinella spiralis（350-400 Trich inella）.Visceral sensitivity of colorectal distension in rats was accessed by electromyogram（EMG） after the colorectal distension（CRD） at different time points before and after infection.Flow cytometry was used to detect the percent of blood Treg.[Results]①The technique of EMG combined with CRD was an effective way to access visceral sensitivity of colorectal distension;②The EMG increased significantly in both 2W and 8W group after Trichinella spiralis infection with 20,40,60mm Hg distention.This accretion was absent in 80mmHg group;③2W after Trichinella spiralis infection,there was a significant decrease of CD4＋CD25＋/CD4＋ in peripheral blood,which was abolished in 8W group. [Conclusion]Both the visceral hypersensitivity and the down-regulation of regulatory T cells presented in the early stage of Trichinella spiralis infection.The regulatory T cells changed back to normal with visceral hypersensitivity remained in the late stage of Trichinella spiralis infection.