OBJECTIVETo investigate endostatin gene therapy of rat corneal neovascularization induced by acid cauterization.

METHODSpBlast-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 gene Bank using NCBIBLAST software. They were then purified with QIAGEN Endofree plasmid maxi kit. Rat corneal neovascularization models were made with 75% AgNO(3) and 25% KNO(3) cauterization. The treatment method was subconjunctive injection of the pBlast-hEndostatin with the control of pBlast-Mcs.

RESULTSpBlast-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.

CONCLUSIONSThe 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.