Microarray Analysis of Retinas from Mice Raised in Dim- and Bright-Cyclic Light: Identification of Differentially Expressed Genes in a Mouse Adaptive Neuroprotective Model

Abstract

Abstract: : Purpose: Retinas of albino mice born and raised in bright cyclic light (300-800 lux) are less susceptible to light-induced apoptosis than retinas of animals born and raised in dim cyclic light (5-10 lux). We have used microarray technology to test the hypothesis that differentially expressed retinal genes are responsible for neuroprotection in bright-reared animals. Methods: Albino mice were born and raised in 3-10 lux or 300-500 lux cyclic light. At 5-6 weeks of age, total retinal RNA was isolated from 4 independent groups from each lighting condition. Retinal RNA and mouse universal reference RNA (Stratagene) were labeled by fluorescent markers Cyanine (Cy)-3 and Cy-5, respectively. The Cy-3 and Cy-5 labeled cDNA probes were hybridized to 16k mouse oligonucleotide microarray. Gene expression from scanned images was quantified using Imagene 5.0 computer software, and changes over 2-fold were considered to be significant. Results: 111 genes had significantly higher levels of expression in retinas from mice raised in bright versus dim cyclic light. Among these are 6 known neuroprotective genes: fibroblast growth factor 13 (FGF13), fibroblast growth factor inducible 16 (FIN16), heat shock protein 70 (HSP70), interleukin 1 alpha (IL1α), Mus musculus interferon gamma receptor 2, and a small inducible cytokine B subfamily member 5 (SCYB5). 73 genes have significantly higher levels of retinal expression in mice raised in dim cyclic light. Conclusions: Albino mice raised in different cyclic light levels have differentially expressed genes, some of which are likely to protect the retina against light-induced apoptosis.

Keywords: apoptosis/cell death • gene microarray • dark/light adaptation