Abstract
Purpose: :
Identification of genes differentially expressed in rat neuroretinas submitted to experimental acute branch retinal vein occlusion (BRVO), to laser treatment, or to light exposure.
Methods: :
Using an in vivo experimental model of venous occlusion by photodynamic thrombosis in Long-Evans rat retinas, we induced acute ischemia by argon laser photocoagulation of venous sites adjacent to the optic nerve head in the right eye of one group of animals. In a second group, right eye retinas were exposed to laser treatment at sites located between major vessels. Finally, a third group of animals had their right eyes exposed to light through a slit lamp. Untreated left eyes served as controls in each animal. Total RNA was extracted from neuroretinas, 30 minutes and 6 hours post treatments, and processed for global gene analysis with Affymetrix microarrays. Genome-wide comparison of transcriptomes was then performed.
Results: :
At 30 minutes, data did not reveal any sequence differentially expressed for the 3 treated groups. At 6 hours, light exposure was definitively excluded as a factor impacting gene expression. However, the expression of 627 and 113 sequences changed, respectively post BRVO and post laser treatment. When comparing transcriptomes of both groups with controls, we identified that the expression profiles of, respectively, 396 and 21 genes were specifically modified. Interestingly, around 80 genes, all upregulated, were common to both treated groups.The majority of differentially regulated genes encode proteins involved in different aspects of a large number of complex pathways, among which we retained: early response to stress, inflammation, response to hypoxia, angiogenesis, apoptosis and neuroprotection.
Conclusions: :
Our microarray analysis revealed changes in gene expression bearing similarities to gene expression results from other ischemia models. Furthermore, it revealed that laser treatment may have an unreported and specific impact on retina’s metabolism.
Keywords: gene screening • retina • gene microarray