Functional Properties of the Water Extract from Eriocheir sinensis (Chinese mitten crab) Via Evaluation of Protective Effects on Reflux Esophagitis Model

Objectives In the study, we investigated the effects of an Eriocheir sinensis water extract on a reflux esophagitis-induced rat model. Background The crab has been used as a traditional medicine and food source in many countries worldwide for a long time, and the crab contains various useful substances such as chitin, protein, calcium carbonate, etc. Materials and Methods All rats were fasted for 24 h and then orally pretreated with saline, Eriocheir sinensis (100 mg/kg), or ranitidine (40 mg/kg). Reflux esophagitis was induced by pylorus and forestomach ligation. Morphological changes in the mucosal damage in the esophagus were analyzed by the ImageJ program. Also, the expression of the inflammatory proteins and cytokine in the esophagus was measured by western blot assay to demonstrate the protective effects of Eriocheir sinensis in reflux esophagitis model. Histological analysis of esophagus was performed by hematoxylin & eosin (H&E) staining. Results In the reflux esophagitis induction group, the esophageal tissue damage caused by the induction of reflux was 60% of the whole. Eriocheir sinensis administration significantly ameliorated esophageal mucosal damage by 40%, also determined by histological evaluation of reflux esophagitis in rats. Eriocheir sinensis was also found to downregulate the expression levels of proteins such as cyclooxygenase-2 (COX-2), tumor necrosis factor-α (TNF-α), and tight junction protein (claudin-5) compared to the reflux esophagitis induction group. In addition, Eriocheir sinensis markedly attenuated the activation of nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB) and the phosphorylation of the inhibitor of NF-κB (IκBα). Conclusion These results indicated that Eriocheir sinensis suppressed the development of esophagitis and modulated inflammation by regulating NF-κB activation. Based on these findings, we concluded that Eriocheir sinensis can protect the esophageal mucosa from reflux esophagitis.