肠易激综合征患者内脏高敏感性的机制研究

Mechanism of hypersensitivity in the patients with irritable bowel syndrome

目的 检测肠易激综合征 (IBS)患者的内脏感觉及其结肠黏膜肥大细胞 (MC)、P物质(SP)和血管活性肠肽 (VIP)的改变 ,探讨MC、SP、VIP对IBS患者内脏高敏感性的作用及其机制。方法 黏膜标本取自 19例正常人和 2 2例腹泻型IBS(D IBS)、2 0例便秘型IBS(C IBS)患者回肠末端、回盲部、升结肠、乙状结肠 ,应用特殊组织化学染色法、免疫组织化学染色法分别对MC、SP和VIP免疫反应阳性神经纤维进行染色 ,应用彩色病理图像分析软件进行分析 ,电镜观察MC及其毗邻结构 ;应用电子气压泵及灌注导管测压仪检测上述患者肛门直肠压力、直肠对容量刺激的感觉及直肠顺应性。结果 IBS组回肠末端、回盲部、升结肠MC明显增多 ,MC显著变异 (P <0 .0 1) ;IBS组结肠黏膜SP、VIP免疫反应阳性神经纤维较正常对照组增多、增粗、阳性强度增强 (P <0 .0 1) ;IBS组SP、VIP免疫反应阳性纤维的阳性强度均值、面积与MC的密度、面积密切相关 (r =0 .3 860～ 0 .663 2 ,P <0 .0 1、P <0 .0 5) ,并可观察到MC与无髓神经末梢及浆细胞等内分泌细胞毗邻或密切接触 ;IBS组肛门直肠括约肌的静息压、收缩压、松弛压与正常对照组相似 (P >0 .0 5) ,感觉阈值、排便阈值、疼痛阈值明显低于正常对照组 (P <0 .0 1) ,直肠顺应性降低 (P <0 .0 1) ,向直肠?

Objective To observe the rectal visceral perception to balloon distention and the changes o f mast cells (MCs), substance P(SP) and the vasoactive intestinal ploypeptide(VI P) in irritable bowel syndrome(IBS), and to investigate their possible roles in IBS. Methods The biopsies of the terminal ileum, the ilecocecal junctio n(ICJ), the ascending colon and the sigmoid colon were stained with histochemist ry fo r the MCs and with immunohistochemistry for SP and VIP in 19 controls, 22 diarrh ea-predominant IBS (D-IBS) patients and 20 constipation-predominant IBS (C-I BS) patients. The results were investigated qualitatively and quantitatively by color image analyzer. The structural relation between MC and nerves or cells was studied through an ultramicroscopy. Rectal visceral perception thresholds to b alloon distention, rectal compliance and anorectal manometry were examined by me ans of electric barastat and perfusion catheter manometer. Results The number of the MCs in the terminal ileum, ICJ and ascen ding colon was significantly elevated in IBS patients ( P <0.01). VIP and SP i n the lamina propria were markedly increased in density and deg ree of immunostaining, compared with those in the controls ( P <0.01). The MCs were close to unmyelinated nerves and plasma cells in lamina propria. In patien ts with IBS, the anorectal resting pressure, squeeze pressure and relaxation pre ssure were similar to those of normal volunteers ( P >0.05); rectal complianc e decreased significantly ( P <0.01). The averagte sensation thresholds, defec ation thresholds and discomfort thresholds were much lower than those in normal volunteers ( P <0.01). All patients had similar minimum relaxation volume to e licit the anorectal inhibitory refulx. Conclusions MC, SP and VIP may play an important role in the gut hy persensitivity in both motor response and visceral perception in IBS patients, a nd the intestinal mucosal MC activity, SP and VIP may be correlated with the vis ceral perception of gut origin.