Research on the Therapeutic Effect of Green Tea Polyphenols in Corneal Alkali Burn in Mice
|Keywords||GTP EGCG corneal alkali burn corneal neovascularization cornealepithelium VEGF|
Objective:To evaluate the therapeutic effect of green tea polyphenols in corneal alkali burn in mice through the establishment of the mouse corneal alkali burn models.Methods:Forty healthy C57/BL male mice were randomly divided into two groups (twenty mice in each group):the control group and GTP group.To establish corneal alkali burn models, left eyes of the mice were treated with1mol/L NAOH soaked filter paper (diameter=2mm) on the center of the corneas for60s.From the day models were established, the mice in GTP group were injected with GTP solution intraperitoneally for14consecutive days,and the mice in control group were administrated with equal amount of0.9%sodium chloride solution instead.We observed the growth of corneal neovascularization(CNV)under slit-lamp microscope,and photos were taken to measure the lengths and areas of CNV.We also observed the corneal epithelium stained with fluorescein sodium under slit-lamp microscope,and photos were taken to measure the restoration ratio of the corneal epithelium.Five mice of each group, which were randomly selected from the two groups, were killed on the1st、3rd、7th、14th day after alkali burn separately.Eyeballs were taken to make tissue sections.Tissue sections were stained with HE to observe the morphology of the corneas, and meanwhile, the number of CNV and inflammatory cells were counted separately.Immunohistochemical analysis was used to determine the expression of vascular endothelial growth factor (VEGF) in corneal organization.Results:1.Results under slit-lamp microscope(1) Compared with the control group, CNV occurred later and grew slower in GTP group, and the lengths of CNV were shorter and the areas of CNV were smaller in GTP group. Comparing the lengths and areas of CNV on the3rd,7th,14th day after alkali burn, there were statistical differences between the control group and GTP group (p<0.05).(2) Compared with the control group, the restoration ratio of corneal epithelium in GPT group was better on every observed day. There were statistical differences between the control group and GTP group on the1st,3rd,7th day after alkali burn (p<0.05).However, there was no statistical difference between the control group and GTP group on the14th days (p>0.05)2.HE staining(1) The amounts of CNV in GTP group were less than the control group on the1st,3rd,7th,14th day after alkali burn, and there were statistical differences between them (p<0.05)(2) The amounts of inflammatory cells in GTP group were less than control group on the1st,3rd,7th,14th day after alkali burn, and there were statistical differences between them (p<0.05).3. ImmunohistochemistryThe expression of VEGF was lower in GTP group than control group on the7th day after alkali burn.Conclusion:1. In the model of corneal alkali burn in mice, intraperitoneal injection of GTP solution can promote the recovery of corneal epithelium, inhibit the formation of CNV, inhibit the infiltration of inflammatory cells, reduce the expression of VEGF in corneal organization.2. Maybe GTP inhibits CNV by inhibiting the expression of VEGF in corneal organization.