Abstract
Purpose::
To screen for retinal genes in chickens that are regulated by myopic defocus, as imposed by positive lenses.
Methods::
Four male white leghorn chicks, aged 9 days, were bilaterally treated with +7D lenses for 24 hours. Four untreated chicks served as controls. The retinae from both eyes of each chick were pooled, RNA was isolated (RNeasy Mini Kit, Quiagen) and labelled cRNA was prepared. These samples were hybridized to Affymetrix GeneChip® Chicken Genome arrays with more than 28000 characterized genes. GC-RMA was used for normalization of the data. The classification of the genes was performed using Ingenuity Pathway Analysis (Ingenuity Systems). Alterations in gene expression of candidate genes with potential relevance were further verified using semi-quantitative real-time RT-PCR.
Results::
Significant changes (p < 0.05, at least 1.5-fold change in expression level) were detected in the expression levels of 132 transcripts. Seventy-three genes (55%) were up-regulated and 59 genes (45%) were down-regulated in the positive lens treated eyes, relative to the control eyes. One of the genes was identified as a growth factor, one as a transporter, two as G-protein coupled receptors, two as transmebrane receptors, three as peptidases, seven as transcription regulators, eight as kinases, 15 as other enzymes, 52 as other genes and the function of 41 genes was unknown. Fifteen genes (seven up-regulated and eight down-regulated genes, e.g. ETV5 (transcription regulator) and GNAT2 (guanine nucleotide binding protein)) were chosen for further investigation using semi-quantitative real-time RT-PCR.
Conclusions::
Since axial eye growth is inhibited in chicks treated with positive lenses, some of the genes identified in this study may be involved in the generation of stop-signals for axial eye growth and provide new targets for pharmacological intervention of myopia development.
Keywords: myopia • gene/expression • retina