Identification of Necroptosis as a Mechanism of Photoreceptor Damage After Retinal Detachment and Nec-1 as a Potential Treatment

Abstract

Purpose: : To explore the role of necroptosis ( a RIP1 kinase dependent cell necrosis) in photoreceptor damage after retinal detachment and the ability of Nec-1 ( an inhibitor of RIP1 Kinase) to act as a neuroprotective agent for photoreceptors

Methods: : Retinal Detachment Model: Retinal detachment was created in the right eyes of Brown Norway rats using subretinal injection of viscoelastic (Provisc). Four eyes received an injection of Provisc with vehicle (control), four eyes received Provisc with zVAD (100 µM) and four eyes received zVAD with Nec-1 (40µM).Cell Death and Necroptosis Assessment: Eyes were enucleated at specified time points and retinas cryo-sectioned and examined histologically. TUNEL assay was performed to quantify photoreceptors with degraded DNA and Photoreceptor degeneration was determined by measuring change in outer nuclear layer (ONL) thickness.

Results: : Three days after the induction of retinal detachment, ONL thickness was 61% of normal in the vehicle-treated control retinal detachment eyes. ONL thickness was improved with treatment to 78% of normal in the zVAD-treated eyes and 93% in the Nec-1-treated eyes (p><0.05). The number of TUNEL positive photoreceptors in eyes with retinal detachment was reduced by 71% (p<0.05) after treatment with zVAD and Nec-1.

Keywords: neuroprotection • retinal detachment • photoreceptors