Effects Of Pigment Epithelium-Derived Factor Peptide On Neovascularization Of Oxygen-Induced Retinopathy In Mice

Objective:To determine the effect of pigement epithelium-derived factor peptide on inhibiting retinal neovascularization in murine model of oxygen-induced retinopathy.Methods:C57BL/6J mice were exposed to 75% oxygen from postnatal day(P)7 to P12 and then returned to room air, which were called OIR model. There were two ways to apply PEDF-peptide on OIR mice, including intravitreal injection and eye drop. Mice in the intravitreal injection group received injection in right eyes, on PI 2 and p17, each 1 ul, while their left eyes served as control. The injection concentration differed from one group to another (0.5 μg/μ,1μg/μL,2 μg/μL). Mice in eye drop group were dripped 3ul peptide to both corneal surface, on P12～16 once per day. This group was subdivided into three treatment groups, each receiving one of the following concentration:0.5 μg/μL,1 μg/μL,2 μg/μL. On P17, mice were killed and eyes were enucleated for quantitation of retinal neovascularization. The proliferative neovascular response was estimated by observing in adenosine diphoshatase(ADPase) stained retina flatmounts and quantitative analyzed by counting the number of new vascular cell nuclei of retina in cross-section. Finally, we programed real time PCR and immunohistochemistry to detect the level of PEDF-mRNA and PEDF protein of retina.Results:(1) Intravitreal injection group:the counts of the new vascular cell nuclei of 0.5 μg/μL,1 μg/μL,2 μg/μuL group as follow:(44.41v±1.46), (43.46±1.20), (38.06±0.95). There was significant difference between 2 μg/μL and 1 μg/μL PEDF peptide were injected. There was no statistical difference between 0.5 μg/μL and 1 μg/μL. All three groups were less neovascular proliferative than OIR group(69.51±1.74) and the left eye group(69.12±1.60). (2) Eye drop group:the counts of the new vascular cell nuclei of 0.5 μg/μL,1 μg/μL,2 μg/μL group as follow: (48.81±1.18), (52.85±1.68), (50.96±1.72). There was no difference between each group, but all were less neovascular proliferative than OIR group. (3) Intravitreal injection group vs Eye drop group:All intravitreal injection group were less neovascular proliferative than Eye drop group. (4) real time PCR and immunohistochemistry to detect the difference of the level of PEDF-mRNA and PEDF protein between air control group, OIR group, intravitreal injection (0.5 μg/μL) group, Eye drop(0.5 μg/μL) group:the later three groups had no differences between each other, but all less than air control group.Conclusions:Both intravitreal injection and Eye drop could inhibit retinal neovascularization. The effects of intravitreal injection showed some certain relation with concentration, which 2 μg/μL group suggested the best. However, The effects of Eye drop group didn’t show any relation with concentration, indicating maybe need higher concentration. It suggested that eye drop of PEDF peptide may be an effectvie approach for the treatment of ischemia-induced retinal neowascular disorders such as retinopathy of prematurity(ROP)...