The relationship of retinal VEGF and retinal IGF-1 mRNA with neovascularization in an acidosis-induced model of retinopathy of prematurity

Purpose: Acidosis-induced retinopathy (AIR) in the neonatal rat provides an alternative model for retinopathy of prematurity (ROP). We studied the relationship of vascular endothelial growth factor (VEGF) retinal mRNA and insulin-like growth factor-1 (IGF-1) retinal mRNA expression with the emergence of neovascularization (NV) in AIR. Methods: Two hundred seventy-five newborn Sprague-Dawley rats were raised in 11 expanded litters of 25. Using our established AIR model, acidosis was induced by twice-daily gavage with NH4Cl from day 2 to day 8 of life (n = 175). Rats were sacrificed at days 5, 8, and 10. Nongavaged rats were used as age-matched controls (n = 100). Retinae from left eyes were dissected, flatmounts were ADPase-stained, and the presence and severity of NV was scored in a masked manner. Individual right retinae were processed for analysis of retinal VEGF and IGF-1 mRNA using quantitative real-time reverse-transcriptase PCR (qRT-PCR). Results: Retinal VEGF mRNA was increased 1.4-fold at day 10 i...