Inhibition of neuronal apoptosis by a metalloporphyrin superoxide dismutase mimic.

The objective of this study was to determine whether free radicals play a pathogenic role in neuronal apoptosis. The ability of Mn(III) tetrakis(benzoic acid) porphyrin (MnTBAP), a superoxide dismutase mimic, to inhibit staurosporine-induced neuronal apoptosis was tested in mixed cerebrocortical cultures. Staurosporine produced concentration-dependent cell death that was markedly inhibited by MnTBAP. Immunocytochemical analyses of cultures for neuron- and astrocyte-specific markers revealed that high concentrations of staurosporine induced the death of both neurons and astrocytes; both cell types were protected by MnTBAP. A less active congener of MnTBAP failed to protect cells against staurosporine-induced apoptosis. MnTBAP also protected cortical cultures against ceramide-induced apoptosis. These results support a role for oxidative stress in neuronal apoptosis.