Upregulation of the FAS–mediated apoptosis pathway in an experimental model of retinal detachment

Abstract

Abstract: : Purpose: : To determine whether the FAS–mediated apoptosis pathway becomes activated in photoreceptor cells following retinal detachment. Methods: : Experimental retinal detachments were created in Brown–Norway rats by injecting 10% hyaluronic acid into the subretinal space. Retinal tissue was harvested at 3 and 7 days after creation of the detachment. Western blot analysis was performed using antibodies against caspase 3, caspase 8, BID, FAS–ligand, and FAS–receptor. Immunoprecipitation was performed to assess for FAS–receptor/FAS–ligand complex formation. Transcription levels of FAS pathway intermediates were assessed as a function of time after retinal detachment using quantitative real–time polymerase chain reaction (qRT–PCR). Immunohistochemical localization was performed on paraffin–embedded sections at 3 and 7 days after retinal detachment. Results: Retinal detachment resulted in the time–dependent transcriptional up–regulation of FAS pathway intermediates. There was also a time–dependent increase in FAS–receptor/FAS–ligand complex formation and activation of caspase 8, BID and caspase 3. These intermediates localized to the outer nuclear layer.Conclusions: The FAS–mediated apoptosis pathway becomes upregulated and activated after retinal detachment, contributing to photoreceptor cell death.

Keywords: apoptosis/cell death • retinal detachment • photoreceptors