Changes Of VEGF And SFlt-1 Levels In Murine Corneal Neovascular Models Induced By Epithelium Defect

PURPOSE.1.To observe the relation betewwn epithelium defect and corneal neovascularization.2.To investigate the changes of VEGF and sFlt-1 levels in murine models induced by corneal epithelium defect.METHODS.Normal adult KM mice were devided into two groups.A state of 360°partial limbal deficdiency combined with complete corneal epithelium debridement was induced in groupⅠ,and complete epithelium debridement in groupⅡ.Corneas were harvested at day 1,3,5,7,10 and day 14.Epithelium restoration,the density of inflammatory cells and goblet cells was observed in HE and PAS sections.The time-dependent area of neovessels was analyzed by immunefluorescence of corneal flatmounts.Content of sFlt-1 mRNA and VEGF protein including bound and free form,was assessed with Real-time RT-PCR and non-reducing western blot.RESULTS.Corneal neovascularization was successfully induced in both groups.The area of neovascularization of groupⅠwas significantly larger than that of groupⅡexcept at day 14.Corneal epithelium reached complete restoration at day 1 in groupⅡ,but the progress was delayed in groupⅠbefore day 5.Although the density of inflammatory cells of groupⅠwas higher in very early stage,no significant difference was observed after day 5.The goblet cells appeared only in groupⅠat day 10 and 14,which represented a gradient from corneal limbus to the center.The content of VEGF protein of both form in groupⅠwas throughout much higher than that of groupⅡ.Expression of sFlt-1 mRNA was down-regulated at day 1 and day 5,but up-regulated at day 3,7,10 and day 14,which appeared like a "W" shape curve.CONCLUSION.1.The delayed restoration of epithelium are induced by limbal deficiency,which results in persistent epithelium defect,reduces the expression of sFlt-1,increases the content of free VEGF protein,and finally promotes corneal neovascularization.2.The expression of sFLt-1,which is dominated by corneal epithelium and imflammation in murine models induced by coreanl epithelium defect,appears like a "W" shape curve.