Antioxidants inhibit the human cortical neuron apoptosis induced by hydrogen peroxide, tumor necrosis factor alpha, dopamine and beta-amyloid peptide 1-42.

Several substances related to the neurodegenerative diseases of Alzheimer and Parkinson, such as hydrogen peroxide, tumor necrosis factor alpha, dopamine and beta-amyloid peptide 1-42, have been shown to induce apoptosis in tumoral cell lines and rat neurons but not in human neurons. Moreover, the role of mitochondria (membrane potential) during neuronal apoptosis is still a matter of debate. We present here, for the first time, in cultured human cortical neurons that the DNA fragmentation induced by these substances was preceded by a decrease of the mitochondrial membrane potential. We have also examined the antiapoptotic effect of the antioxidants glutathione, N-acetyl-cysteine and ascorbic acid. All these antioxidants inhibited the apoptosis induced by hydrogen peroxide, tumor necrosis factor alpha, dopamine and beta-amyloid peptide 1-42, since they were able to inhibit completely the mitochondrial membrane potential depolarization and the DNA fragmentation.