OCLN and irritable bowel syndrome: Previous studies reported that alteration in epithelial tight junctions (TJ) proteins, such as Zonula Occludens (ZO-1), Claudins, and Occludin, led to epithelial barrier dysfunction and contributed to the pathogenesis of IBS and pain (Coeffier et al. 2010; Martinez et al. 2012; Nusrat et al. 2000).