TJP1 and ulcer disease: These effects resulted from DSS-induced negatively charged sulfated groups on the colonic epithelium, resulting in erosion and bleeding, epithelial damage, characterized by tight junction disruption (occludin, ZO-1, claudins), apoptosis, and barrier dysfunction, leading to ulcers, nutrient malabsorption, increased intestinal permeability, and mucosal ulceration.