Effects of edaravone on N-methyl-D-aspartate (NMDA)-mediated cytochrome c release and apoptosis in neonatal rat cerebrocortical slices

N-Methyl-D-aspartate-mediated neurotoxicity is known to involve nitric oxide production and to be augmented in an environment of reactive oxygen species. We used TUNEL staining and homogenous cytosolic immunoreactivity of cytochrome c in an acute brain slice preparation to investigate the influence of edaravone (3-methyl-1-phenyl-2-pyrazolin-5-one), a free radical scavenger, on N-methyl-D-aspartate-induced apoptosis. Cerebrocortical slices were obtained from parietal lobes of 7-day-old Sprague-Dawley rats, superfused with well-oxygenated artificial cerebrospinal fluid, and metabolically recovered. Subsequent 30-min exposures to 10 mu M N-methyl-D-aspartate in treated and untreated slices were followed by 4 h of recovery superfusion with oxygenated artificial cerebrospinal fluid. Outcomes were compared for three groups of slices: "the N-methyl-D-aspartate-only group"; "the edaravone treatment group", which had 20 mu M edaravone present throughout and subsequent to N-methyl-D-aspartate exposure; the "control group", in which slices were superfused only with oxygenated artificial cerebrospinal. fluid. At the conclusion of recovery (t = 4 h), the percentage of TUNEL-positive cells in the edaravone treatment group (7.0 +/- 3.3%) was significantly reduced from the percentage for the N-methyl-D-aspartate-only group (21.9 +/- 4.1%), and insignificantly greater than the percentage for the control group (3.4 +/- 2.1%). Percentages of cytochrome c positive cells at t = I h were significantly increased (p < 0.01) in the N-methyl-D-aspartate-only group (30.6 +/- 1.9%) compared to percentages for both the control group (11.4 +/- 2.6%) and the edaravone treatment group (15.2 +/- 2.1%). Edaravone's reduction in TUNEL staining and cytochrome c release provides evidence of reactive oxygen species mechanisms and antioxidant benefits in cytochrome c-mediated apoptosis during N-methyl-D-aspartate excitotoxicity. (c) 2006 ISDN. Published by Elsevier Ltd. All rights reserved.