| Objective:Tea was used as drug in China early, and later became the people's drinking. Major components of tea-tea polyphenols has antioxidant, anti-cancer, anti-viral, anti-bacterial, anti-radiation effects. In ischemia-reperfusion injury, the produce of oxygen free radicals and the secretion of VEGF plays an extremely important role. Ischemia and hypoxia induced cell function change, cell membrane permeability increase, large quantities of oxygen free radicals produce which damage cells directly, and the lever of VEGF increase which injury vascular endothelial cells. In the review of gastrointestinal ischemia-reperfusion, there are a large number of domestic and foreign literature, but the report about the direct gastrointestinal protection and mechanism of PPT is rare. Though detecting the SOD and MDA content of plasma and the intercellular connection of gastric mucosal vascular endothelial cells, this study tried to observe the stomach vascular endothelial protection of PPT by antioxidant and free radical elimination effects, and then detected the VEGF and CD34 expressions of vascular endothelial gastric mucosa, and observed the ultrastructure changes of gastric mucosal capillary endothelial, for exploring the direct protection of PPT on stomach under gastric ischemia-reperfusion.Methods:35 adult male SD rats were randomly divided into 7 groups(n=5, in each group): control group, imitative operation group, operation group, 20 mg/kg PPT group, 40 mg/kg PPT group, 80 mg/kg PPT group, 160 mg/kg PPT group. While the gastric ischemia animal model was set up 30min, reperfusioned and injected PPT by vein. In reperfusion of 1 h, 2 h, 6 h, 12 h, collected plasma samples, and reperfusion 12h later, collected gastric mucosal samples.①Testing the SOD and MDA content by Spectrophotometric colorimetric method.②Observing the change of VEGF and CD34 in gastric mucosal endothelial cells by immunofluorescence staining.③By using electron microscopy method to observe the ultrastructure change of gastric mucosal capillary endothelial cells.Results:①The SOD content: each IR group was significantly higher than operation group, imitative operation group and control group in which correspond time point; 40 mg/kg PPT group was the highest among the IR groups.②The MDA content: 20 mg/kg PPT group, 40 mg/kg PPT group, 80 mg/kg PPT group was lower obviously than operation group, imitative operation group and control group in which correspond time point; 80 mg/kg PPT group was the lowest among them; 160 mg/kg PPT group was lower slightly than operation group, but higher than control group and imitative operation group.③The CD34 expression of epithelial cells of stomach mucosa capillary: each IR group was significantly higher than operation group, but lower slightly than imitative operation group and control group.④The VEGF expression of epithelial cells of stomach mucosa capillary: Each IR group was obvious lower than operation group, and slightly higher than control group and imitative operation group.⑤PPT can significantly alleviate the ultrastructure injury of gastric mucosal capillary endothelial cells induced by gastric ischemia reperfusion.Conclusion: PPT has a protective function on gastric mucosa injury induced by ischemia-reperfusion, and its major mechanism probably connected with eliminating oxygen free radicals and reconstructing gastric mucosa vascular endothelial. |
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