Isorhamnetin alleviates esophageal mucosal injury in a chronic model of reflux esophagitis.

Gastro-esophageal reflux disease is one of the most common disorders in gastroenterology. The aim of this work was to investigate the protection of isorhamnetin against esophageal mucosal injury in rats with chronic reflux esophagitis (RE). Chronic RE model was established through fundus ligation and partial obstruction of the pylorus in rats. Then, the rats were treated with isorhamnetin (5 mg/kg) daily for a period of 14 days. Through histological and gross assessment, it was found that administration of isorhamnetin alleviated esophageal mucosal injury in RE rats. Treatment of RE rats with isorhamnetin improved esophageal barrier function, through upregulating proteins expression of occludin and zonula occludens-1 (ZO-1) and downregulating proteins expression of matrix matalloproteinases-3 (MMP3) and -9. Administration of isorhamnetin decreased CD68-positive cells and mRNA levels of IL-6, TNF-α, and IL-1β in the esophagus of RE rats. Administration of isorhamnetin downregulated inducible nitric oxide synthase (iNOS) protein expression and decreased production of nitric oxide (NO) and 3-nitrotyrosin in the esophagus of RE rats. Administration of isorhamnetin enhanced heme oxygenase-1 (HO-1) activities and reduced malondialdehyde (MDA) levels in esophagus of RE rats. Additionally, treatment with isorhamnetin inhibited p38 MAPK and NFκB activation in RE esophagus. In conclusion, isorhamnetin attenuated esophageal mucosal injury in rats with chronic RE, possibly by suppressing formation of cytokines and infiltration of inflammatory cells, inhibiting p38 and NFκB pathways, and enhancing HO-1 activity.