A Novel Model Of Retinopathy Of Prematurity In Normobaric Hyperoxic Conditions With Fewer Oxygen Supply In The Rat

Abstract

Purpose: : To examine the changes in the retinal vasculature with different oxygen concentrations from common retinopathy of prematurity (ROP) models and to determine a novel and practical ROP model.

Methods: : A sample of 14 newborn Spraque - Dawley rat was prospectively divided in two groups. First group (study group) (n=7) newborn rats within 4 hours (h) of birth were placed into an oxygen chamber in which they were exposed to 95% oxygen for 4 h per day followed by normoxic laboratory conditions for 20 h. This cycle was repeated for 14 days (d). Control group (n=7) was followed in normobaric normoxic conditions. At postnatal day 14 (P14) two groups were placed into room air for 7 d. At postnatal day 21 two groups were examined with indirect ophtalmoscopy and fundus photographs. All eyes were enucleated for vascular endothelial growth factor (VEGF) analysis and rats were sacrificed by decapitation.

Results: : In the study group under normobaric hyperoxic conditions retinal neovascularization and peripheral avascular retina was determined in 85% of rats with indirect ophtalmoscopic examination. Furthermore, mean VEGF concentrations of vitreous in study group were 239.5 pg/ml; and of control group was 55.5 pg/ml (p<0.05).

Conclusions: : Based on our study and previously published data, different oxygen concentrations is primary responsible for retinal neovascularization. Our new ROP model is more practical and simply applicable for all retinal neovascularization studies.

Keywords: retinopathy of prematurity • vascular endothelial growth factor