Effects Of Recombinant Pigment Epithelium-Derived Factor On Neovascularization Of Oxygen-Induced Retinopathy In Mouse

Objective To determine the effect of recombinant plasmid pET28a/pigment epithelium-derived factor(PEDF) on inhibiting retinal neovascularization in a murine model of oxygen-induced retinopathy.Methods Human recombinant PEDF was expressed in the human embryonic kidney 293 cell line and purified by ammonium sulfate precipitation and cation exchange chromatography.C57BL/6 mice were exposed to 75%oxygen from postnatal day(P)7 to P12 and then returned to room air. Mice in the treatment group(n=136) received intravitreal injections of pET28a/PEDF in left eyes,while their fight eyes served as control.The injection method differs from one group to another.There are also blank control groups and a golden standard control group.At P17 or P23,mice were killed and eyes enucleated for quantitation of retinal neovascularization.The proliferative neovascular response was estimated by observing the vascular pattern in adenosine diphosphatase(ADPase) stained retina flatmounts and quantitative analyzed by counting the number of new vascular cell nuclei extending into the internal limiting membrane in cross-sections. Results There were significant differences after 2μg(left eyes 13.42±2.75 vs right eyes 36.00±2.66) and 3μg(left eyes 12.67±2.94 vs right eyes 38.28±2.59) PEDF were injected(P=0.000).There was no effect on retinal vessels when single dose of 2μg PEDF was injected at the time of P12,while there were responses when two or three times of injections of 2μg PEDF were injected,and there was no statistical difference between two or three times of injections(P＞0.05).It is effective for intravitreal injection at the time of early neovascularization when intraperitoneal injection is of no use.Conclusions These data indicate that intravitreal injection of recombinant plasmid pET28a/PEDF could inhibit retinal neovascularization without overt harm to retinal morphology.It suggests that localized administration of PEDF may be an effective approach for the treatment of ischemia-induced retinal neovascular disorders such as retinopathy of prematurity(ROP).