Abstract
Abstract: :
Purpose: Ischemic conditions have been implicated as a factor in the progression of glaucoma. Experimentally induced ischemia–reperfusion leads to neurodegeneratation in the inner retina resembling glaucoma–associated damage. The purpose of this study was to assess the alterations in gene expression profiles associated with the onset of degeneration. Methods: Following 1 h ischemia, induced by raising the pressure in the anterior chamber, RNA was isolated from total retina at reperfusion intervals (1 h, 2h, 6h, 12h). Gene expression levels of selected genes were determined in individual samples using quantitative PCR. After confirming the upregulation of c–fos (1h, 2h) or loss of parvalbumin (6h, 12h), a pool was composed of each experimental group and of all contralateral untreated/sham retinas. These pools were used as probes on a series of 22K rat Agilent–micro arrays, following a common reference design. Results: At 1 h and 2 h reperfusion, alterations in the gene expression profile were restricted to about 400 genes, while at later intervals about 1600 genes were changed. Statistical analysis of the combined dataset, using ANOVA, identified a total of 800 altered genes (P < 0.0001). Verification of the array results with qPCR on a selection of trancripts showed a good correlation of the changes (R2 = 0.78). Moreover, previously described changes in the expression level of AMPA–type glutamate receptors and amacrine cell–specific markers such as parvalbumin and glycine transporter (Glyt1) were confirmed showing a high quality of the data set. Conclusions: Further analysis and classification of the altered genes with respect to their biological function will be carried out using bioinformatics. This will give more insight in the processes that underlie the ischemia–mediated damage to the inner retina and their possible involvement in glaucomatous degeneration.
Keywords: retina • ischemia • neuroprotection