Grape seed proanthocyanidins protect retinal ganglion cells by inhibiting oxidative stress and mitochondrial...

Grape seed proanthocyanidins (GSP) are known as condensed tannins and have been used as an anti-oxidant in various neurodegenerative diseases. In our study, GSP was used as a daily dietary supplement and the neuroprotective effects were evaluated on the retinal ganglion cells (RGCs) in the retinal tissues in glaucomatous DBA/2D (D2) mice. D2 mice and age-matched non-glaucomatous DBA/2J-Gpnmb⁺ (D2-Gpnmb⁺) mice were fed with GSP or a control diet for up to 6 months. The intraocular pressure (IOP), RGC survival, glial fibrillary acidic protein (GFAP), the levels of apoptotic proteins, and the expression of oxidative stress markers in retinal tissues were determined. In our study, the neuroprotective effects of GSP on retinal tissues were confirmed, as evidenced by (a) GSP inhibited the IOP elevation in D2 mice; (b) GSP enhanced RGC survival and mediated the apoptotic protein expression; (c) GSP suppressed GFAP expression; and (d) the oxidative stress and the levels of mitochondrial reactive oxygen species were regulated by GSP. Our findings indicate that GSP has promising potential to preserve retinal tissue functions via regulating oxidative stress and mitochondrial functions.