Protective effect of propolis on ethanol-induced acute gastric injury in rats

Objective To explore the preventive effect of propolis on ethanol-induced acute gastric injury in rats.Methods Fifty male Wistar rats were randomly divided into five groups:a control group,a model group,and low-,medium- and high-dose propolis groups (given propolis by gavage at the dosages of 40,80,160 mg/kg/d);all the rats were sacrificed one hour after the last treatment of 14 days.The extent of gastric mucosal lesions and ulcer index were determined with visual inspection and Guth integral method.The gastric histopathological changes was observed with hemato-xylin-eosin (HE) staining.The level of prostaglandins E2 (PGE₂) and tumor necrosis factor-alpha (TGF-α) in gastric mucosa were measured by means of radioimmunoassay and enzyme-linked immunosorbent assay (ELISA).Results General observation on gastric tissue showed that the gastric mucosa surface of the control group was smooth and without hyperaemia and erosion,with the ulcer index of zero.Multiple hemorrhage and edema were observed in the rats of model group,with a significantly increased ulcer index (44.0±19.4);while,the mucosa damages were significantly alleviated,with a decreased ulcer index (19.8±8.8)(P<0.05) in the rats of medium-dose propolis group compared with those of the model group.Pathological observation revealed exfoliation of epithelial cells,neutrephil infiltration,and large number of erythrocyte in lamina propria of gastric mucosa in the rats of model group and these pathological injuries were obviously alleviated in the rats of medium-dose propolis group compared with those of the model group.The content of PGE₂ (156.60±16.34 pg/mg) in gastric mucosa decreased significantly but serum TNF-α (111.64±19.95 pg/mL)increased significantly in the rats of model group compared to those of the control group (both P<0.05).The PGE₂ content (198.75±20.99 pg/mg)in gastric mucosa increased significantly but serum TNF-α(73.93±14.96 pg/mL)decreased significantly in the rats treated with medium-dose propolis compared to those of the model (both P<0.05).Conclusion Propolis has a protective effect on ethanol-induced acute gastric injury in rats and the effect may relate to the regulation of secretion and synthesis of PGE₂ and the inhibition of inflammation reaction in gastric mucosa.