Background: In recent years, the rat has become a commonly-used animal model for the study of retinal diseases. Similar to other tissues, the retina undergoes significant functional changes during maturation. Aiming to gain knowledge on additional aspects of retinal maturation, we performed gene expression and histological analyses of the rat retina during maturation.
Methods: Rat retinas were dissected at three time points. Histological examination of the samples was performed, and the expression levels of retinal genes were evaluated using the rat whole-genome microarray system. Quantitative real-time PCR analysis was used to validate selected expression patterns. Various statistical and bioinformatic tools were used to identify differentially expressed genes.
Results: The microarray analysis revealed a relatively high number of highly expressed non-annotated genes. We identified 603 differentially expressed genes, which were grouped into six clusters based on changes in expression levels during the first 20 weeks of life. A bioinformatic analysis of these clusters revealed sets of genes encoding proteins with functions that are likely to be relevant to retinal maturation (potassium, sodium, calcium, and chloride channels, synaptic vesicle transport, and axonogenesis). The histological analysis revealed a significant reduction of outer nuclear layer thickness and retinal ganglion cell number during maturation.
Conclusions: These data, taken together with our previously reported electrophysiological data, contribute to our understanding of the retinal maturation processes of this widely-used animal model.