Inhibition of corneal neovascularization by liposome mediated plasmid encoding endostatin with RGD sequence / 眼科研究

ABSTRACT

Background It has been demonstrated that αvβ3/αvβ5 and α5β1 integrins are overexpressed in neovascular tissue.Consequently,peptide containing the RGD (Arg-Gly-Asp) sequence,which exists in ligands of integrins,is effective in targeting therapeutic reagents to neovascular endothelium.ObjectivePresent study aims to investigate the antiangiogenetive effects of liposome mediated plasmid encoding endostatin with RGD sequence on alkali burn-induced corneal neovascularization (CNV) in rabbits.MethodsCNV models induced by alkali burn were established in 72 eyes of 36 New Zealand white rabbits by putting the filter paper with 1 mol/L NaOH at the central cornea for 20 seconds.The animal models were divided into four groups randomly.0.2mL of liposome and plasmid encoding RGD-ES complex (liposome mediated pCI-RGD-ES injection group),liposome and plasmid encoding ES complex (pCI-ES injection group),liposome and carrier plasmid (pCI) complex (pCI-ES injection group),and PBS were subconjunctivally injected respectively in the models from four groups twice a week for two weeks.The growth status of CNV was observed on day 1,3,7,14 after alkali burn under the slim lamp microscope.Experimental animals were sacrificed on the 3rd,7th and 14th day and the expression of VEGF in CNV was detected by immunohistochemistry.The number of corneal microvessels was counted based on the number of CNV cross-section under the light microscope.ResultsCNV area was significantly smaller in liposome mediated pCI-RGD-ES injection group and pCI-ES injection group compared with PBS group at different time points (P＜0.01),but no significant difference was seen in CNV area between pCI-ES injection group and PBS group at different time points (P＞0.01).The changes of number of corneal microvessels was followed a similar fashion as the change of CNV area.Expression of VEGF in cornea was obviously stronger in pCI-ES injection group and PBS group than liposome mediated pCI-RGD-ES injection group and pCI-ES injection group.ConclusionEndostatin with RGD sequence could effectively inhibit corneal neovascularization,and liposome is proved to be a potent carrier in gene transfer.