Protective effect of Nitro-Oleic Acids in neovascularization, vascular regrowth and neurodegeneration in Oxygen-Induced Retinopathy model

VAGLIENTI, MARIA V.; SUBIRADA, PAULA V.; JORAY, B.; PAZ, MARÍA C.; BARCELONA, PABLO F.; BONACCI, GUSTAVO; SÁNCHEZ, MARÍA C.

Denver, Colorado

Congreso; Annual Meeting of The Association for Research in Vision and Ophthalmology ARVO; 2022

ARVO

Purpose : Inflammation, oxidative and nitrosative stress are involved in neovascular retinopathies (NR). Nitro-fatty acids are important electrophilic signaling mediators with anti-inflammatory, antioxidant and cytoprotective properties. Therefore, our aim is to evaluate the effect of Nitro-oleic acid (NO2-OA) in a mouse model of oxygen-induced retinopathy (OIR).Methods : OIR mouse model was used. Briefly, C57BL/6 mice (n=35) were exposed to 75% O2 from P7 to P12, after which they were brought to room air (RA) for additional five (P17) or fourteen days (P26). Age-match mice maintained in RA (n=25) were used as controls. OIR mice were intraocular (i.o.) injected with 5 μM of NO2-OA (n=22) or vehicle (n=13) at P12 and intraperitoneal (i.p) with 15 mg/Kg of NO2-OA or vehicle at P14, P17, P20, P23. At P17 or P26 mice were sacrificed. Some eyes were fixed for whole mount staining of retina and microscopy and other retinas were used for Western blot or RT-PCR assays. Retinal functionality was assessed by scotopic electroretinography (ERG) in dark-adapted mice. Amplitudes and latencies of a- and b-waves from ERG were recorded at P17 or P26. Finally, the NO2-OA effect on neovascularization was evaluated by tube formation assay in bovine aortic endothelial cells (BAEC). GraphPad Prism was used for statistical analysis.Results : NO2-OA induced vascular regrowth (p<0.05) and decrease pathological neovascularization (p<0.001) at P17 OIR. Interestingly, RT-PCR revealed a significant increase in VEGF levels in OIR mice respect to RA mice (p<0.0001), but not difference was found between NO2-OA treatment and vehicle (p=0.9978). In addition, WB of neural retinas showed that NO2-OA prevented glial stress by decreasing GFAP (p<0.0001) in OIR model at P17 (p=0.3160). In the other hand, NO2-OA did not modify the (p=0.0177) levels of GS at P17 (p=0.0003). At P26, ERG shown that NO2-OA treated mice prevented the decrease in b-wave amplitude (p=0.1362) as well as increasing the expression of total Caspase-3 (p=0.0004) as a marker of cellular protection. Finally, it was observed that NO2-OA affected neovascularization by decreasing the total segment length (p<0.0001) and number of tubular structures (p<0.0001) in BAEC cells.Conclusions : These findings suggest that NO2-OA could be beneficial for retinal cells in order to attenuate vascular and non-vascular alterations in NR.