Expression and Significance of VEGF and PEDF in Choroidal Neovascularization Induced by Krypton Laser in BN Rats

Objective To study the expression of vessel endothelial growth factor (VEGF) and pigment epithelium-derived factor (PEDF) in choroidal neovascularization (CNV),and to investigate their expression and significance on CNV induced by krypton laser in BN rats. Methods Five groups of 30 BN rats were photocoagulated by krypton laser in single eye.Three days, 1 week, 2 weeks, 3 weeks and 4 weeks after photocoagulation, the expression of VEGF, PEDF and factor Ⅷ related antigen (FⅧR ∶Ag) was observed by immunohistochemical method. Results FⅧR ∶Ag positive staining cells formed vessels in the lesion 1 week after photocoagulation;the expression of FⅧR ∶Ag gradually increased till 3-4 weeks. VEGF expression was observed in the ganglion cells, inner nuclear layer, retinal pigment epithelial cells,and the vascular endothelial cells in normal retina and choroid of BN rat. VEGF expressed in the ganglion cells, inner nuclear layer, the vascular endothelial cells,and lesion of outer nuclear layer and choroid after photocoagulation. PEDF expressed in the ganglion cells,inner nuclear layer,and retinal pigment epithelial cells in normal BN retina. After photocoagulation, the expression of PEDF was observed in the ganglion cells, inner nuclear layer, retinal pigment epithelial cells, and the lesions of outer nuclear layer and choroid. From 3 days to 4 weeks, the expression density of FⅧR ∶Ag and VEGF in the lesions gradually increased(P0.05), however, the expression density of PEDF decreased (P0.05).The expression of FⅧR ∶Ag was positively correlated with that of VEGF(r=0.89,P0.05)and inversely correlated with that of PEDF during the development of CNV(r=-0.84,P0.05). Conclusions CNV is positive correlated with the expression of VEGF and inversely correlated with that of PEDF. The unbalanced expression between VEGF and PEDF may contribute to the main reason for the formation and development of CNV.