Use of microarray analyses to determine the effect of hyperoxia and hypoxia on gene expression in early oxygen-induced retinopathy (OIR).

Different inbred strains of rats differ in their susceptibility to OIR, an animal model of human retinopathy of prematurity. We examined gene expression profiles in Fischer 344 (F344, resistant to OIR) and Sprague Dawley (SD, susceptible to OIR) rats at the early time points of day 5 (in response to hyperoxia) and day 6 (in response to relative hypoxia) to identify gene pathways related to the underlying genetic cause of the phenotypic differences observed between strains. To examine gene expression changes in rat strains which are resistant and susceptible to OIR, four different experimental conditions were analysed: F344 cyclic hyperoxia (O2) exposed, F344 room air (RA) exposed, SD O2 exposed and SD RA exposed. Two samples of pooled RNA, comprising of 3 individual rats from 2 separate litters, was used for each experimental condition, for each time point of interest. Pooled RNA from age-matched room air-exposed rats were used as controls.