Pullan R D
Department of Surgery, Ysbyty Gwynedd, Bangor.
Ann R Coll Surg Engl. 1996 Mar;78(2):85-91.
Human colonic mucosal protection is not fully understood but may in part rely on a layer of mucus gel adherent to the mucosa. Ulcerative colitis may occur if mucosal protection breaks down. Two studies are presented, both of which relate to the aetiology of ulcerative colitis. First, a layer of adherent mucus gel was demonstrated by a simple, reliable method. Measurements of mucus layer thickness were made in freshly resected colonic specimens and shown to increase from a mean of 107 microns on the right colon to 155 microns in the rectum. In ulcerative colitis the layer is significantly thinner or absent, whereas in Crohn's disease the colonic mucus layer is significantly thicker. Second, the relationship between smoking and colitis is explored by a double-blind, randomised and placebo-controlled trial of transdermal nicotine in active disease. Significant clinical benefit was seen, indicating nicotine may be both useful therapeutically and the component of tobacco smoke that acts to protect against colitis. Since smoking and nicotine have actions on mucosae and mucus in other organs, it is argued that there is a mucus deficiency in ulcerative colitis that smoking acts to reverse.
人类结肠黏膜保护机制尚未完全明晰，但可能部分依赖于一层附着在黏膜上的黏液凝胶。如果黏膜保护功能失效，可能会引发溃疡性结肠炎。本文介绍了两项研究，均与溃疡性结肠炎的病因相关。首先，通过一种简单可靠的方法证实了存在一层附着的黏液凝胶。对新鲜切除的结肠标本进行黏液层厚度测量，结果显示从右结肠的平均107微米增加到直肠的155微米。在溃疡性结肠炎中，该层显著变薄或缺失，而在克罗恩病中，结肠黏液层则显著增厚。其次，通过一项针对活动性疾病患者的经皮尼古丁双盲、随机、安慰剂对照试验，探讨了吸烟与结肠炎之间的关系。结果显示出显著的临床益处，表明尼古丁可能在治疗上有用，且是烟草烟雾中起到预防结肠炎作用的成分。鉴于吸烟和尼古丁对其他器官的黏膜和黏液有作用，有人认为溃疡性结肠炎存在黏液缺乏，而吸烟可起到逆转作用。
