Intestinal mucus barrier: A potential therapeutic target for IBD

Intestinal mucus, a viscoelastic medium with mucin2 (MUC2) as its main component, covers the surface of intestinal epithelial cells and protects the intestine from invasion, forming the first barrier of the intestinal tract. Unlike the small intestine, where the mucus layer is a single layer, the colonic mucus layer can be divided into a sterile inner layer and an outer layer with bacterial colonization. Many of the substances in the mucus layer have beneficial effects on the intestinal epithelium, but the mucus layer is often affected by a variety of factors, mainly microbiological, dietary, and immunological. Inflammatory bowel disease (IBD) is a disease of increasing morbidity worldwide, with a complex etiology and a high relapse rate. In recent years, the mucus barrier in IBD has received increasing attention and is considered a key factor in the pathogenesis of IBD. Loss of goblet cells (GCs) and changes in the composition and properties of the mucus layer material are commonly found in the colon of IBD patients. Damage to the mucus layer may make it easier for microorganisms to access the intestinal epithelium and cause inflammation. There are currently a number of herbs and other therapies that can be used to treat IBD and repair the damaged mucus barrier. This review highlights the important role of the mucus layer in IBD and the therapies that target the mucus layer in IBD.