Aim: Hyperoxia-induced photoreceptor degeneration occurs preferentially in the inferior retina of C57BL/6 J mice. This study investigates differential gene expression in the inferior and superior retina of C57BL/6 J mouse, before and after hyperoxic stress.
Methods: At the age of P (postnatal day) 83-90, mice were placed in constant normoxia or hyperoxia (75% O(2)) for 2 weeks. Retinas from control and exposed mice were removed and RNA was extracted from superior and inferior regions. The RNA from 2 animals (1 male and 1 female) at each condition was extracted, purified and hybridized to an Affymetrix MouseGene 1.0 ST Array to elucidate gene expression. Experiments were run in triplicate and analysis of the expression patterns was performed using GeneSpring and Partek Genomics Suite softwares.
Results: Over 400 genes showed significant differential expression by location and treatment using 2-way ANOVA analysis. In the control material, no genes showed a differential expression greater than twofold between inferior and superior retina. After hyperoxic stress, 154 genes in the inferior and 30 genes in the superior retina showed a greater than twofold change in expression. Among those, genes such as Edn2, GFAP, Bcl3 and C1qb showed expression differences of greater than three fold between inferior and superior retina. Real time PCR was used to verify gene expression of control genes as well as genes of interest.
Conclusion: These microarray data may provide clues for identifying previously unknown factors and pathways responsible for the vulnerability of inferior retina to hyperoxic stress and for the eventual identification of therapeutic targets.