Involvement of Purinergic P2 Receptors in Experimental Retinal Neovascularization

Abstract

Purpose: The present study was aimed to investigate the expression of purinergic P2 receptors in oxygen-induced retinal neovascularization. Methods: Immunohistochemistry was used to study the expression of purinergic P2Y2 and P2X2 receptors in the neonatal mouse retina during normal vascular development and after oxygen-induced retinopathy (OIR). The effect of the P2 antagonists, suramin and PPADS, on the extent of oxygen-induced retinal neovascularization was analyzed. Results: In normal mice, the expression of P2Y2 receptors was weak throughout the retina, whereas P2X2 receptor expression was detected in the outer plexiform layer. In mice treated with oxygen, P2Y2 expression was detected in the ganglion and in the nerve fiber layers, whereas P2X2 expression was found in the inner and outer plexiform layers. Oxygen-induced preretinal neovascularization was strongly inhibited by the P2 antagonists, suramin (p < 0.05) and PPADS (p < 0.05), and this was accompanied by a down-regulation of P2X2 receptor expression in the inner plexiform layer in suramin-treated mice. Conclusions: The data suggest that purinergic P2 receptors are involved in neovascularization associated with OIR.

KEYWORDS:

• angiogenesis
• hypoxia
• P2 receptors
• retina
• ROP