Abstract
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 was to evaluate the effect of nitro-oleic acid (NO2-OA) in the OIR mouse model.
Methods :
Briefly, C57BL/6 mice (n=35) were exposed to 75% O2 from postnatal day (P)7 to P12, after which they were brought to room air (RA) for additional 5 (P17) or 14 days (P26). Age-match mice maintained in RA (n=25) were used as controls. OIR mice were intraocular injected with 5μM of NO2-OA (n=22) or vehicle (n=13) at P12 and intraperitoneal at P14, P17, P20, P23 with 15mg/Kg of NO2-OA or vehicle. At P17 or P26 mice were sacrificed. Some eyes were fixed for whole mount staining of retina and microscopic analysis and other retinas were used for WB or RT-PCR assays. Retinal functionality was assessed at P17 or P26 by scotopic ERG in dark-adapted mice. Some eyes were fixed to obtain cryosections for TUNEL assay. GraphPad Prism8 was used for statistical analysis.
Results :
NO2-OA induced vascular regrowth (p<0.05) and reduced neovascularization (p<0.001) at P17 OIR. 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). Regarding PEDF, neither significant changes were observed in OIR respect to RA mice (p=0.1394) nor between NO2-OA and vehicle (p=0.1849). In addition, WB of neural retinas showed that NO2-OA prevented glial stress (p<0.0001) induced in OIR at P17 (p=0.3160). NO2-OA did not modify the decrease (p=0.0177) in GS at P17 (p=0.0003). The ERG analysis showed a significant decrease in b-wave amplitude in OIR compared to RA mice. Also, a- and b- wave latencies were significantly increased in OIR respect to RA. Besides, WB analysis of retinas from RA and OIR mice revealed decreased levels of caspase-3 protein at P26 OIR. Finally, quantitative analysis showed that TUNEL-positive cells were significantly higher in P26 OIR compared to RA (p<0.05). All of these pathological events were prevented by NO2-OA (p=0.1362) (p=0.0004) (p<0.05).
Conclusions :
In conclusion, our study underscores the role of NO2-OA as potential treatment in the pathogenesis of NR in order to attenuate vascular and non-vascular alterations.
This abstract was presented at the 2024 ARVO Annual Meeting, held in Seattle, WA, May 5-9, 2024.