肠易激综合征患者肠道屏障——紧密连接改变的示踪电镜观察

Changes in tight junction of intestinal mucosa in patients with irritable bowel syndrome:a study with tracing electron microscope

目的观察肠易激综合征(IBS)患者肠道屏障-紧密连接的改变,探讨IBS排便性状改变的机制。方法严格按照罗马Ⅱ标准选择IBS便秘型、腹泻型患者及正常对照组各10例,利用硝酸镧示踪电镜细胞化学技术,观察其回肠末端及升结肠粘膜紧密连接形态的变化。结果10例便秘型IBS回肠末端粘膜及升结肠粘膜与正常对照组一样,紧密连接结构正常;10例腹泻型IBS中7例回肠末端粘膜及8例升结肠粘膜可见到部分细胞间紧密连接间隙增宽,示踪剂有不同程度的外渗现象。4例有感染性腹泻病史的患者中3例回肠末端及升结肠粘膜均有上述改变。结论IBS患者的排便性状改变可能与紧密连接的结构和功能改变有关,紧密连接的开放性增强可能是导致腹泻性IBS腹泻的原因之一。

Objective To investigate the presence of tight junction （TJ） changes of the intestinal mucosa, and elucidate the possible mechanism for changes in bowel evacuation in patients with irritable bowel syndrome （IBS）. Methods In 10 normal control subjects, 10 patients with constipation predominant IBS （C-IBS） and 10 with diarrhea predominant IBS （D-IBS）, biopsies were taken from the terminal ileum and ascending colon. Lanthanum nitrate tracing electron microscope and cytochemical technique were employed to observe TJ changes in the intestinal mucosa. Results Like the control subjects, C-IBS patients had normal TJ structure in the intestinal mucosa, whereas D-IBS patients exhibited some abnormalities in TJ structure either in their terminal ileum （7 in 10） or ascending colon （8 in 10）, revealed by TJ gap widening with lanthanum nitrate extravasation into the surrounding tissue. Such changes were also observed in 3 of the 4 patients with a history of acute infectious diarrhea. Conclusion The changes in the intestinal mucosal TJ structure and function might contribute to altered bowel evacuation in patients with irritable bowel syndrome.