肠易激综合征患者结肠黏膜辣椒素受体、P物质和肥大细胞变化的研究

背景:腹痛是一般人群中最常见的肠道症状,肠易激综合征(IBS)患者的腹痛症状更为严重、频繁,然而其发生机制尚不明确。目的:分析IBS患者结肠黏膜中与痛觉和内脏高敏感相关的辣椒素受体VR1、P物质(SP)和肥大细胞(MC)的变化,探讨IBS患者内脏高敏感和腹痛的发生机制。方法:39例IBS患者[腹泻型IBS(IBS-D)21例,便秘型IBS(IBS-C)18例]和18名健康人纳入研究。受检者于结肠镜检查时在回盲部和乙状结肠取活检,行VR1、SP免疫组化染色和MC改良甲苯胺蓝染色。结肠镜检查前采用视觉模拟评分法行疼痛评分。结果:IBS患者乙状结肠VR1、回盲部和乙状结肠SP免疫反应阳性细胞以及回盲部MC数量显著多于正常对照组(P0.01),IBS-D与IBS-C组间则无明显差异。IBS-D和IBS-C患者的腹痛评分均与VR1呈正相关(r=0.553,P=0.009;r=0.592,P=0.010)。结论:IBS患者结肠黏膜中VR1、SP免疫反应阳性细胞和MC数量显著增多,VR1与腹痛评分呈正相关,三者可能参与了IBS患者内脏高敏感和腹痛的发生机制。

Alterations of Capsaicin Receptor, Substance P and Mast Cells in Colonic Mucosa of Patients with Irritable Bowel Syndrome

Background： Abdominal pain is the most commonly seen intestinal symptom in general population and being more severe and frequent in patients with irritable bowel syndrome （IBS）, but the mechanisms underlying abdominal pain in IBS are poorly understood. Aims： To investigate the alterations of capsaicin receptor VR1, substance P （SP） and mast cells （MC）, which are correlated with pain sensation and visceral hypersensitivity in colonic mucosa of IBS patients, and the pathogenesis of visceral hypersensitivity and abdominal pain in IBS. Methods： Ileocecal and sigmoid biopsies were obtained from 39 IBS patients, including 21 diarrhea-predominant IBS （IBS-D）, 18 constipation-predominant IBS （IBS-C）, and 18 healthy subjects during colonoscopy. VRI and SP were quantified following immunohistoehemical stain, and modified toluidine blue stain performed for assessing MC. The severity of abdominal pain was scored by visual analogue scale before colonoscopy. Results： A significant increase in numbers of VR1 and SP immunoreactive ceils in ileocecal and/or sigmoid mucosa, as well as in number of MC in ileocecal mucosa, was observed in biopsies from IBS patients as compared with the controls （P〈0.01）, while no significant difference was found between IBS-D and IBS-C. In correlation analysis, the scores of abdominal pain in IBS-D and IBS-C were positively correlated with the number of VR1 immunoreactive cells （r=0.553, P=0.009; r=0.592, P=0.010）. Conclusions： The numbers of VRI, SP immunoreactive cells and MC in colonic mucosa of IBS patients are increased significantly; furthermore, VR1 is positively correlated with the score of abdominal pain. These findings suggest that VRI, SP and MC might contribute to the visceral hypersensitivity and abdominal pain in patients with IBS.