Experimental inhibition of corneal neovascularization by endostatin gene transfection in vivo

Objective To investigate endostatin gene therapy of rat corneal neovascularization induced by acid cauterization.Methods pBlast-hEndostatin and pBlast-Mcs were identified by digestion with Nhe Ⅰand Sal Ⅰ, by PCR reaction, by sequence, and then by alignment of PCR products with the geneBank using NCBIBLAST software. They were then purified with QIAGEN Endofree plasmid maxi kit. Rat corneal neovascularization models were made with 75% AgNO3 and 25% KNO3 cauterization. The treatment method was subconjunctive injection of the pBlast-hEndostatin with the control of pBlast-Mcs.Results pBlast-hEndostatin was found to contain the human endostatin gene. The rat corneal neovascularization induced by acid cauterization was significantly suppressed after subconjunctive injection of the pBlast-hEndostatin with inhibition rates of 37%, 40.2%, and 42.8% respectively on the sixth, tenth, and fifteenth day. The inhibition rate for the density of corneal neovascularization was 40%. However, no inhibition effect on the length of the neovascularization and corneal inflammatory cells was observed. Corneal neovascularization areas were positively correlated with edema and corneal opacity.Conclusions The plasmid of pBlast-hEndostatin contained the human endostatin gene. The rat corneal neovascularization induced by acid cauterization can be partially inhibited by subconjunctive injection of the pBlast-hEndostatin mediated by liposomes. Endostatin produced by transfected fibroblast cells directly inhibits corneal neovascularization. This is not caused by inflammatory reaction inhibition.