MMP9 and gastroesophageal reflux disease: The core targets of HWJND for the treatment of GERD include TNF, IL6, IL1B, MMP9, CXCL8 EGFR, etc. Among them, TNF, IL6, and IL1B are inflammatory cytokines, which can not only damage the esophageal mucosal barrier function of the GERD mouse [30–32] but activate acid-sensitive receptors on afferent nerves and epithelial cells of the esophageal mucosa, stimulating neurogenic inflammation and pain, leading to DIS and further increase in epithelial barrier permeability [33].