Grape Seed Proanthocyanidins Protect N2a Cells against Ischemic Injury via Endoplasmic Reticulum Stress and Mitochondrial-associated Pathways

Abstract

Background/objective: Grape seed proanthocyanidins (GSPs) are a group of polyphenolic bioflavonoids, which possess a variety of biological functions and pharmacological properties. We studied the neuroprotective effects of GSP against oxygen-glucose deprivation/reoxygenation (OGD/R) injury and the potential mechanisms in mouse neuroblastoma N2a cells.

Methods: OGD/R was conducted in N2a cells. Cell viability was evaluated by CCK-8 and LDH release assay. Apoptosis was assessed by TUNEL staining and flow cytometry. Protein levels of cleaved caspase-3, Bax and Bcl-2 were detected by Western blotting. CHOP, GRP78 and caspase-12 mRNA levels were assessed by real-time PCR. JC-1 dying was used to detect mitochondrial membrane potential. ROS levels, activities of endogenous antioxidant enzymes and ATP production were examined to evaluate mitochondrial function.

Results: GSP increased cell viability after OGD/R injury in a dose-dependent manner. Furthermore, GSP inhibited cell apoptosis, reduced the mRNA levels of CHOP, GRP78 and caspase-12 (ER stressassociated genes), restored mitochondrial membrane potential and ATP generation, improved activities of endogenous anti-oxidant ability (T-AOC, GXH-Px, and SOD), and decreased ROS level.

Conclusion: Our findings suggest that GSP can protect N2a cells from OGD/R insult. The mechanism of anti-apoptotic effects of GSP may involve attenuating ER stress and mitochondrial dysfunction.

Keywords: Grape seed proanthocyanidins; apoptosis; brain ischemia; endoplasmic reticulum stress; mitochondrial dysfunction; oxygen-glucose deprivation/reoxygenation..