Oxidative neurotoxicity in rat cerebral cortex neurons: Synergistic effects of H2O2 and NO on apoptosis involving activation of p38 mitogen-activated protein kinase and caspase-3

Authors

  • Jiz-Yuh Wang,

    1. Graduate Institute of Life Sciences, National Defense Medical Center, Taipei, Taiwan, Republic of China
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  • Andrew Y. C. Shum,

    1. Department and Institute of Pharmacology, National Yang-Ming University, Taipei, Taiwan, Republic of China
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  • Yi-Jung Ho,

    1. Department of Physiology, National Defense Medical Center, Taipei, Taiwan, Republic of China
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  • Jia-Yi Wang

    Corresponding author
    1. Graduate Institute of Life Sciences, National Defense Medical Center, Taipei, Taiwan, Republic of China
    2. Department of Physiology, National Defense Medical Center, Taipei, Taiwan, Republic of China
    • Department of Physiology, National Defense Medical Center,161, Sec.6, Ming-Chuan E. Rd. Taipei, Taiwan, Republic of China
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Abstract

Oxidative stress in the brain has been increasingly associated with the development of numerous human neurological diseases. Microglia, activated upon neuronal injury or inflammatory stimulation, are known to release superoxide anion (·Omath image), hydrogen peroxide (H2O2), and nitric oxide (NO), thereby further contributing to oxidative neurotoxicity. The reaction of NO and ·Omath image, forming the toxic peroxynitrite (ONOO), has been proposed to play a pathogenic role in neuronal injury. However, the interactions between H2O2 and NO during oxidative stress, which may promote or diminish cell death, is less clear. In this study, we explored oxidative neurotoxicity induced by H2O2 plus NO in primary cultures of rat cerebral cortex neurons. As the mechanisms may involve reactions between H2O2 and NO, we monitored the production of ONOOand reactive oxygen species (ROS) throughout the experiments. Results indicated that the NO donor S-nitroso-N-acetyl-D, L-penicillamine (SNAP) and H2O2 by themselves elicited neuronal death in a concentration- and time-dependent manner. Sublytic concentrations of H2O2 plus SNAP were sufficient to induce neuronal apoptosis as determined by DNA laddering and fluorescent staining of apoptotic nuclei. Transient ONOOincrease was accompanied by rapid H2O2 decay and NO production, whereas ROS slowly decreased following treatment. Furthermore, p38 mitogen-activated protein kinase (MAPK) activation and the cleavage of caspase-3 were observed. Conversely, inhibition of p38 MAPK and caspase-3 significantly reduced apoptotic death induced by H2O2 plus SNAP. These data suggest that H2O2 and NO act synergistically to induce neuronal death through apoptosis in which activation of p38 MAPK and caspase-3 is involved. © 2003 Wiley-Liss, Inc.

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