Gene expression profile of hyperoxic and hypoxic retinas in a mouse model of oxygen-induced retinopathy

PURPOSE. To determine a profile of gene expression in retinas of a murine model of oxygen-induced retinopathy (OIR). METHODS. OIR was induced in C57BL/6N mice by exposing postnatal day (P)7 pups to 75% oxygen for 5 days and then returning them to room air at P12. Gene microarrays containing more than 47,000 transcripts were used to study the changes in gene expression in retinas isolated immediately (P12) and at 12 hours (P12.5) after exposure to hyperoxia. The retinas of P12 mice raised under normoxic conditions served as control subjects. Quantitative RT-PCR and multiplex ELISA were performed to validate the microarray analyses. RESULTS. The expression of 83 gene transcripts was significantly altered in the hyperoxic P12 retinas. These genes were classified as cellular components or were associated with development, metabolism, transport, stress response, cell adhesion, inflammation, or vision. The genes related to retinal growth, such as Pdgfb and Robo4, which are associated with vascular development, were downregulated. In contrast, the expression levels of 95 genes were significantly altered in the hypoxic P12.5 retinas, which contained several known hypoxia- regulated genes including Vegfa and Hif1a. The differentially expressed genes were broadly clustered into the development, inflammation, metabolism, signaling, antiapoptosis, cellular component, transport, glycolysis, and vision groups. Those associated with organogenesis (e.g., Vegfa, Igfbp3, Tnfrsf12a, and Nestin) and to inflammation (e.g., Ccl3,Ccl4, and MHCs) were upregulated. The results of quantitative RT-PCR and multiplex ELISA were in agreement with the microarray data. CONCLUSIONS. These alterations in gene expression may determine the hyperoxic growth retardation, postischemic inflammation, neovascularization, and remodeling in retinas of murine OIR.