[Protective effect of Polygonati Rhizoma aqueous extract on gastric mucosal injury in mice induced by overtaking pungent substances and alcohol via TRAF1/ASK1/JNK pathway]

Abstract

This study aims to investigate the effect and potential mechanism of Polygonati Rhizoma aqueous extract in protecting mice from gastric mucosal injury(stomach Yin deficiency). ICR mice were administrated with the mixture of pungent substance extract and alcohol by gavage once a day for 6 weeks to establish the mouse model of gastric mucosal injury with gastric Yin deficiency. The modeled mice were randomized into three groups of model and Polygonati Rhizoma aqueous extract administrated at 0.5 g·kg~(-1) and 1.0 g·kg~(-1) according to the body weight. The mice were then continuously administrated with the molding agent once a day, and those in the Polygonati Rhizoma aqueous extract groups were additionally administrated the extract for 7 weeks. During this period, traditional Chinese medicine syndrome indicators related to gastric Yin deficiency were tested. After the last administration, the gastric tissue was collected to observe the histomorphological changes. The activities of antioxidant enzymes in the gastric homogenate were measured, and the levels and expression of proinflammatory cytokines in the gastric tissue were measured by enzyme-linked immunosorbent assay and immunohistochemistry, respectively. The expression levels of proteins in the tumor necrosis factor receptor(TNFR)-associated factor 1(TRAF1)/apoptosis signal regulating kinase 1(ASK1)/c-Jun N-terminal kinase(JNK) pathway were determined by Western blot, and those of apoptosis factors were determined by immunofluorescence. The results showed that the Polygonati Rhizoma aqueous extract alleviated the stomach Yin deficiency in mice, ameliorated gastric mucosal lesions, increased the activities of antioxidant enzymes in the gastric tissue(P<0.05, P<0.01), lowered the levels of pro-inflammatory cytokines in the gastric tissue(P<0.05, P<0.01), down-regulated the expression levels of proteins in the TRAF1/ASK1/JNK pathway(P<0.01) and pro-apoptotic factors in the gastric tissue, and up-regulated the expression of B-cell lymphoma-2(Bcl-2). The results suggested that the Polygonati Rhizoma aqueous extract could alleviate the symptoms of stomach Yin deficiency, such as hunger without desire to eat, thirst, and dry stool, and mitigate the gastric mucosal injury caused by overtaking pungent substances and alcohol by inhibiting the TRAF1/ASK1/JNK pathway to reduce apoptosis and inflammation in the gastric tissue.

Keywords: Polygonati Rhizoma; TRAF1/ASK1/JNK pathway; apoptosis; gastric mucosal injury; stomach Yin deficiency.