The Impact Of Subconjuctivally Injected Conbercept On Experimental Corneal Neovascularization In Rabbit Model

PartⅠAlkali Burn-induced Animal Model of Corneal NeovascularizationObjective: To form the rabbit modle of corneal nevascularization using alkali injury.Methods: 12 adult New Zealand rabbits were randomly divided into three groups:group A(4 rabbits),group B(4 rabbits),group C(4 rabbits).Every left eye was used.Whatman filter papers(8mm)were soaked in 1mol/L Na OH solution and then applied on the surface of the middle of the cornea for 30 seconds for groug A,20 second for group B,10 second for group C.All 6 animals were monitored daily.Digital pictures were taken on days 1,4,7 and 14.Image analysis was performed on The area of neovascularization.On day 14,the rabitts cornea was observed by HRT3 and corneal specimens were analyzed histopathologically.Results: In group A,the corneal nevascularization(NV)buds emerged in day 4,The average aera of NV were 7.25±1.56mm2,on day 7 the average aera of NV were35.46±16.56mm2,on day 14 the avrage aera were 57.72±19.87mm2;In group B,the NV buds emerged in day 5,on day 7 the avrage aera of NV were 22.3±17.89mm2,its more smaller than group A(P<0.05),on day 14 the avrage aera of NV were40.74±14.47mm2,its more smaller than group A(P<0.05).In group C,there was no NV after alkail burning.Under the HRT3 corneal confocal microscope,there were some blood vessels and numbers of inflammatory cells inside the substrate,stromal cells were activated,the basal layer epithelial were in hyperplasia.Conclusion: 1 mol/L Na OH burning the cornea for 30 s can form the rabbits modle of NV safely.There was no corneal ulcer or corneal perforation occurred.The blood vessels were formed on the limbal conjunctival and increased towards the alkial burning areas.Part ⅡThe Impact of Subconjuctivally Injected Conbercept on Experimental Corneal Neovascularization in Rabbit ModelObjective: To investigate the value of conbercept in experimental corneal nevascularization in rabbit model.Material and methods: 44 adult New Zealand rabbits were randomly divided into five groups: group A(9 rabbits),group B(9 rabbits),group C(9 rabbits),group D(9rabbits),group E(8 rabbits).Every left eye was used.Whatman filter papers(8mm)were soaked in 1mol/L Na OH solution and then applied on the middle surface of the cornea for30 seconds.On day 1 after alkali burning,group A was treated with 0.1 ml/1mg of Conbercept,group B was was treated with 0.1 ml /1mg of Ranibizumab,group C was was treated with 0.1 ml 0.9% Na CL,Group D don’t do any processing,group E as normal control group,neither do alkali burns nor subconjunctival injection any drugs.All44 animals were monitored daily after alkali burning.Digital pictures were taken on days4,7,14 and 21.Image analysis was performed on the area of neovascularization,a ascertain number of rabbits were killed respectively.The aqueous humor was collected for detection the concentration of VEGF,corneal specimens were analyzed histopathologically and Immunohistochemical Staining of CD-31 and LYVE-1.Results: The inflammation and NV intensity in group A and B were were significantly lower than group C and D on day 14,21(P<0.05).The surface areas of induced corneal neovascularization were significantly smaller in groups A and B compared with group D,C on days 7,14(P<0.05),Group A were smaller than group B on day 14(P<0.05),There were no differences observed in group C and D.The concentrations of VEGF in groups A and B were significantly lower than in group C and D on days 7,14 and 21,P<0.05,the concentration of VEGF in group A were significantly lower than group B on day 14,P<0.05.Immunohistochemical analysis confirmed the reduced of lymphatic vessels counting in group A and B compared with the control group on day 7 and 14(P<0.05).The NV area was positively correlated with the concentration of VEGF in aqueous humor(R = 0.744,P = 0.744)after alkali burn.the lymphatic vessels counting were positively correlated with the concentration of VEGF in aqueous humor(R = 0.632,P = 0.632).Conclusion: Early subconjunctival administration of Conbercept and Ranibizumab may successfully inhibit alkali-induced corneal neovascularization and corneal lymphangiogenesis in alkali burning animal model.The inhibit effect was related with the reduces of VEGF levels.