Effects of pigment epithelium-derived factor on oxygen-induced retinopathy in rats

Background Retinopathy of prematurity (ROP) is a causing-blindness eye disease.Neovascularization is the major pathological event of ROP.Pigment epithelium-derived factor (PEDF) is thought to play an important role of anti-neovascular effect.Objective Present study was to observe the effects of PEDF on the retinopathy of rats with oxygen exposure.Methods Seven-day-old newborn clean Wistar rats were raised in normal air environment or high oxygen environment (O2 volume 75%±2%) respectively.PEDF or PBS was intraperitoneally injected in the rats at age of 12 days,14 days and 16 days after born.Total 50 rats were randomly divided into normal air group,normal+PEDF group,high oxygen group,hyperoxygen+PBS group,hyperoxygen+PEDF group.Retinal stretches were prepared after perfusion of Chinese ink via chambers heart in 17-day-old rats.The diameter and coverage rate of retinal vessels were measured to evaluate the development of vessels in the rats of various groups,and the numbers of new blood vessels breaking into the retinal inner limit membrane were calculated in 17-day-old rats and compared among different groups.Results Retina flat-mounts presented increasing neovascular tufts in high oxygen group and hyperoxygen+PBS group compared to normal air group and normal+PEDF group.Neovascular tufts were decreased in hyperoxygen+PEDF group in comparison to high oxygen group and hyperoxygen+PBS group.The diameter of retinal vessels and network of vessels were normal in 13-day-old rats of normal air group,but the vessels were thinner in the high oxygen group (P0.01).In the 17-day-old rats,retinal vessels were significantly thinner and the coverage rate of peripherial vessels was obviously increased in comparison with normal group,normal+PEDF group and hyperoxygen+PEDF group in high oxygen group and hyperoxygen+PBS group (P0.01).No significant differences in vessels diameter,coverage rate of vessel between normal air group,normal+PEDF group or hyperoxygen+PEDF group (P0.05).The vessel diameter,caverage rate of peripherial vessel and neovessel numbers in hyperoxygen+PEDF were similar to those of normal air group (P0.05).Conclusion High oxygen environment can induce the neovascular retinopathy.PEDF may arrest the formation of abnormal vessels during the development of new born rats.