Characterization of retinal nucleolin expression in an oxygen-induced retinopathy model

Abstract

Purpose : Retinopathy of prematurity (ROP) is a vasoproliferative disorder of the retina, affecting premature infants, which is an important cause of childhood blindness worldwide. The current therapy of ROP is focused on laser theapy alone or combined with intravitreal anti-VEGF molecules; however, the use of intravitreal anti-VEGF medications is associated with elevated intraocular pressure and other systemic adverse events. Our group has identified that nucleolin is expressed on aberrant corneal neovessels and its expression is VEGF-dependent. The aim of the present study is to identify the nucleolin presence un retinal neovessels in an oxigen-induced retinopathy (OIR) mouse model.

Methods : OIR model was performed in C57BL/6 mouse strain following ARVO guidelines for animal research in visual science. The experimental mice (OIR group) were exposed to 75% oxygen during 5 days at seven postnatal days (P7); afterwards, they were exposed to normoxic atmosphere. The control group was exposed to normoxic atmospehere all the time. The eyeballs from both groups were obtained at different days (P12, P13, P15, P17, and P19). Histopathology assays were performed to analyze the retinal architecture as well as to determine the neovessels formation. Immunofluorescence assays were performed to analyze nucleolin localization in retinal tissue, and double immunofluosecence assays were carried out to identify whether nucleolin protein presence was localized in OIR-retinal generated neovessels.

Results : A significant increase in retinal neoangiogenesis was observed in OIR mice in comparison with the control group. In the control group, the retinal architecture was normal; whilst, there was a disruption in the retinal architecture in the OIR group. Interestingly, nucleolin presence was observed on endothelial cell surface of aberrant retinal blood vessels of ROP group; in contrast to the OIR group, there was not an expression of nucleolin on normal blood vessels. All these changes were more evident at P17 of the OIR group.

Conclusions : Taken together these results, suggest that nucleolin expression in aberrant angiogenesis could be a marker in ROP disorder. The absence of the expression of this protein in blood vessels of normal retinal tissue suggest a possible target to treat ROP disease.

Acknowledgements: CONACYT-Problemas Nacionales 2015-311; DGAPA-PAPIIT-UNAM IN215617

This abstract was presented at the 2019 ARVO Annual Meeting, held in Vancouver, Canada, April 28 - May 2, 2019.