Study On The Expression Of PEDF, VEGF And Ang-2 In Experimental Choroidal Neovascularization

Objective: To study the expression of PEDF, VEGF and Ang-2 in the experimental CNV, and to investigate the mechanism of PEDF, VEGF and Ang-2 in the forming progress of CNV. Methors: 24 BN rats were photocoagulated by krypton laser in double eyes as the experiment group, the other 2 BN rats were done nothing as the control. The development of CNV was examined by FFA and the histology after photocoagulation. The retina was processed for immunohistochemistry of PEDF, VEGF and Ang-2 on days 1,3,7,14,21 and 28 days after photocoagulation. The experimental data were expressed as the mean±S.D. and statistical significance was determined by ANOVA or t-test. Resulets: 1. PEDF expressed in the ganglion cells, inner nuclear layer, RPE in normal BN retina. After photocoagulation, the expression of PEDF was also found in the lesions of outer nuclear layer and choroids. From 3 days to 28 days after photocoagulation, the expression density of PEDF in the lesions decreased(P<0.05). 2. VEGF expressed in the ganglion cells, the inner nuclear layers, the RPE and the retinal and choroidal vascular endothelial cells in normal eyes. In laser retina, it was also found in the lesion of CNV. The expression density was the strongest at the 14 days(P < 0.05) after photocoagulation. 3. Ang-2 was not detected in normal retina. After photocoagulation, Ang-2 expressed in the ganglion cells, the inner nuclear layers and the lesion of CNV. The highest expression density of Ang-2 was observed at 7 days(P<0.05) after photocoagulation. Conclusions:1. The down-regulation of PEDF may be one of the main reasons for the formation and development of CNV. 2. VEGF and Ang-2 play a role in the development of CNV. 3.PEDF and VEGF are significantly expressed in experimental CNV , the unbalance between their expressions may play an important role in the development of CNV.