The antioxidant EPC-K1 attenuates NO-induced mitochondrial dysfunction, lipid peroxidation and apoptosis in cerebellar granule cells

In this study we investigated the effects of nitric oxide (NO) on cultured cerebellar granule cells. Exposure to NO donors, S-nitrosoglutathione (GSNO ; 250 mu M) or sodium nitroprusside (SNP; 500 mu M), triggered apoptosis in immature cultures of cerebellar granule cells, which was characterized by chromatin condensation, nuclei fragmentation, and DNA laddering. Exposure o f cerebellar granule cells to NO donors led to a decrease in the mitochondr ial transmembrane potential and intracellular ATP content, which suggested that NO treatment caused mitochondrial dysfunction. NO treatment also induc ed oxidative stress in cerebellar granule cells as measured by thiobarbitur ic acid (TBA) assay. Pretreating cells with L-ascorbic acid 2-[3,4-dihydro- 2,5,7,8-tetramethyl-2-(4,8,12-trimethyltridecyl)-2H-1-benzopyran-6-yl-hydro gen phosphate] potassium salt (EPC-K1), a novel antioxidant, attenuated NO- induced mitochondrial dysfunction and oxidative stress re, some extent, and prevented the cells from apoptosis. The results of the present investigati on suggest that a superoxide/peroxynitrite-mediated oxidative stress may be an important pathway leading to NO-associated neuronal damage. Pretreating cells with the antioxidant EPC-K1 attenuated NO-induced neurotoxicity by s cavenging superoxide/peroxynitrite and;or its breakdown products. (C) 1999 Elsevier Science Ireland Ltd. All rights reserved.