National Hepatobiliary & Enteric Surgery Research Center, Ministry of Health, Central South University, Changsha 410008, China.
BMC Gastroenterol. 2012 Jul 20;12:91. doi: 10.1186/1471-230X-12-91.
Irritable bowel syndrome (IBS) is a common functional bowel disorder. The post-infectious IBS (PI-IBS) occurs in IBS patients with a history of intestinal infection preceding the onset of symptoms. However, the underlying cause of PI-IBS is not fully understood, and the purpose of this study was to investigate the immune regulatory mechanism of PI-IBS.
Participants enrolled in this study were divided into three groups including PI-IBS patients (n = 20), IBS patients without a history of infection (non-PI-IBS, n = 18), and healthy controls (n = 20). The expression levels of the Th1-derived cytokines IFN-γ and IL-12, and the Th2-derived cytokines IL-4 and IL-10 in the mucosal specimens, and in the ascending colon, the descending colon, and the rectal segments were measured by RT-PCR and western blot.
The IFN-γ mRNA levels in the intestinal mucosa were significantly higher in the PI-IBS group than in the non-PI-IBS or control group (both P < 0.05), but there was no difference between the non-PI-IBS and control groups. A trend toward IFN-γ protein upregulation was found in the PI-IBS group, while the IL-12 and IL-4 mRNA and protein levels were not different between any groups. The IL-10 mRNA and protein levels in the PI-IBS group were both significantly lower than in the non-PI-IBS or control groups (P < 0.05, respectively), but there was no difference between the non-PI-IBS and control groups. There were no differences in the cytokine mRNA and protein levels among the ascending colon, the descending colon, and the rectum of all groups.
An increase in IFN-γ levels and a decrease in IL-10 levels were found in the intestinal mucosa of PI-IBS patients, suggesting that the infection may affect the Th1/Th2 balance. Thus, the dysregulation of the immune response is likely an important cause of IBS.
肠易激综合征（IBS）是一种常见的功能性肠病。感染后肠易激综合征（PI-IBS）发生在有肠道感染史且症状出现前的 IBS 患者中。然而，PI-IBS 的根本原因尚不清楚，本研究旨在探讨 PI-IBS 的免疫调节机制。
本研究纳入的参与者分为三组，包括 PI-IBS 患者（n=20）、无感染史的 IBS 患者（非 PI-IBS，n=18）和健康对照者（n=20）。通过 RT-PCR 和 Western blot 检测黏膜标本和升结肠、降结肠和直肠段中 Th1 衍生细胞因子 IFN-γ 和 IL-12 以及 Th2 衍生细胞因子 IL-4 和 IL-10 的表达水平。
PI-IBS 组肠黏膜 IFN-γ mRNA 水平明显高于非 PI-IBS 组或对照组（均 P<0.05），而非 PI-IBS 组与对照组之间无差异。PI-IBS 组 IFN-γ 蛋白呈上调趋势，而 IL-12 和 IL-4 mRNA 和蛋白水平在各组之间无差异。PI-IBS 组 IL-10 mRNA 和蛋白水平均明显低于非 PI-IBS 组或对照组（分别为 P<0.05），而非 PI-IBS 组与对照组之间无差异。各组升结肠、降结肠和直肠的细胞因子 mRNA 和蛋白水平均无差异。
PI-IBS 患者肠黏膜中 IFN-γ 水平升高，IL-10 水平降低，提示感染可能影响 Th1/Th2 平衡。因此，免疫反应失调可能是 IBS 的重要原因。
