Abstract
Abstract: :
Purpose:We previously reported that Angiotensin II (AII) potentiates vascular endothelial growth factor-induced angiogenic activity in bovine retinal endothelial cells. The goal of the present study was to investigate the effects of AII on retinal vascular cell survival. Methods:C57BL/6J and Angiotensin type 1a receptor knock out (AT1a KO) mice were exposed to 75% O2 from postnatal day 7 (P7) to P12, then return to room air. To study the retinal vessel maturity, vascular endothelial cells and pericytes were stained with isolectin B4 and anti-Desmin antibody on the whole mount retinas. Avascular and vascular area were evaluated using NIH image ver.1.61. To quantitate the anti-apoptotic effect of AII, the bovine retinal endothelial cells were incubated for 24hrs with serum free medium containing AII at various concentrations. Results:No significant difference of the retinal vascular development, vascular endothelial growth factor expression, the vascular area and the pericyte coverage were found between both type of mice on P7. On P12, AT1a KO mice showed 50.5% avascular area whereas wild type mice 38.6% (p<0.01). Vascular endothelial cells completely covered by pericytes and there were no exposed endothelium at the each time point. AII dose-dependently inhibited apoptosis of bovine retinal endothelial cells under a serum-deprived state with maximal inhibition at 50% (p<0.0001) of the control apoptotic rates. Conclusion:The results indicates that AII play an important role in the survival of the reintal vascular endothelial cells via AT1a receptor.
Keywords: 572 retinopathy of prematurity • 417 gene/expression • 323 apoptosis/cell death