In vitro antioxidant neuroprotective activity of BN 80933, a dual inhibitor of neuronal nitric oxide synthase and lipid peroxidation

BN 80933, a dual inhibitor of neuronal nitric oxide synthase and lipid peroxidation, prevents in vivo brain ischemic/reperfusion injury. In the present study, BN 80933 was shown to protect neurons from hypoxia-induced cell death in primary cultures of cortical neurons. BN 80933 prevented lactate dehydrogenase activity elevation induced by hypoxia, displaying an IC50 value of 0.15 +/- 0.05 mu M This effect was likely due to the antioxidant properties of BN 80933 because Trolox, but not N-G-nitro-L-arginine, also elicited protection. The antioxidant property of BN 80933 was then further investigated on HT-22 cells subjected to buthionine sulfoximine- or glutamate-induced glutathione depletion. The relative order of potency of the various compounds to inhibit oxidative stress-induced neuronal death (BN 80933 > U104067 > butylated hydroxytoluene > 17 beta-estradiol > Trolox > vitamin E) correlated with their ability to inhibit brain membrane lipid peroxidation (correlation coefficient = 0.939). BN 80933 afforded protection even when added 6 h after glutamate exposure. BN 80933 did not reverse intracellular glutathione depletion but prevented elevation of the level of 8-epiprostaglandin F-2 alpha (8-isoprostane), which appeared to be a delayed phenomenon. In conclusion, BN 80933 induces a potent cytoprotection that may be mediated by inhibition of delayed lipid peroxidation.