Attenuation of staurosporine-induced apoptosis, oxidative stress, and mitochondrial dysfunction by synthetic superoxide dismutase and catalase mimetics, in cultured cortical neurons

Neuronal apoptosis induced by staurosporine (STS) involves multiple cellula r and molecular events, such as the production of reactive oxygen species ( ROS). In this study, we tested the efficacy of two synthetic superoxide dis mutase/catalase mimeties (EUK-134 and EUK-189) on neuronal apoptosis, oxida tive stress, and mitochondrial dysfunction produced by STS in primary corti cal neuronal cultures. Exposure of cultures to STS for 24 h increased lacta te dehydrogenase (LDH) release, the number of apoptotic cells, and decrease d trypan blue exclusion. Pretreatment with 20 muM EUK-134 or 0.5 muM EUK-18 9 significantly attenuated STS-induced neurotoxicity, as did pretreatment w ith the caspase-1 inhibitor, Ac-YVAD-CHO, but not the caspase-3 inhibitor, Ac-DEVD-CHO. Posttreatment (1-3 h following STS exposure) with 20 muM EUK-1 34 or 0.5 muM EUK-189 significantly reduced STS-induced LDH release, in a t ime-dependent manner. Exposure of cultures to STS for I h produced an eleva tion of ROS, as determined by increased levels of 2,7-dichlorofluorescein ( DCF). This rapid elevation of ROS was followed by an increase in lipid pero xidation, and both the increase in DCF fluorescence and in lipid peroxidati on were significantly blocked by pretreatment with EUK-134. STS treatment f or 3-6 h increased cytochrome. c release from mitochondria into the cytosol , an effect also blocked by pretreatment with EUK-134. These results indica te that intracellular oxidative stress and mitochondrial dysfunction are cr itically involved in STS-induced neurotoxicity. However, there are addition al cellular responses to STS, which are insensitive to treatment with radic al scavengers that also contribute to its neurotoxicity. (C) 2001 Academic Press.