Evaluation of Neuroprotective Effect of hybrid compound SA-2 Nanosuspension in Optic Nerve Crush Mouse Model.

This study examines the cytoprotective effects of hybrid antioxidant-nitric oxide (NO) donating compound SA-2 nanosuspension in normal trabecular meshwork-5 cells (NTM-5) and optic nerve crush (ONC) induced-mouse retinal ganglion cell (RGC) death model. SA-2 was encapsulated in poly-lactic-co-glycolic acid (PLGA) nanoparticles and reported earlier. Total nitrite concentrations of SA-2-NPs was determined using Griess assay in both buffer and NTM-5 cell supernatants. NTM-5 cells were treated with tert-butyl hydrogen peroxide (TBHP, EC50 = 5.5mM) at varying concentrations of SA-2 NPs (1, 0.5, 0.25, 0.125 % w/v) and cell viability was measured. 12-week-old C57BL/6J mice were subjected to ONC injury in the left eye and were administered with either vehicle or 1% SA-2-NPs via intravitreal injections (2uL) or eye drops (5uL). Pattern ERG (PERG) was used to assess retinal function and RGC survival was determined using RBPMS-positive RGCs. Data were presented as mean ± SEM, n=3-8. 1% SA-2-NPs dose dependently increased NTM-5 cell viability and total nitrite concentrations (~50%) lasting over 4 days. There was significant improvement in PERG amplitudes (1.7-1.9 times) following SA-2-NP administration as well as increased RGC numbers (by ~20%) relative to ONC-ed eyes. SA-2 nanosuspension shows strong positive trend in protecting RGC's from oxidative stress-induced apoptosis in ONC rodent model. Further investigation is being done for improved dosing and signaling changes in response to SA-2 NPs therapy.