Effect of dehydroepiandrosterone and its sulfate metabolite on neuronal cell viability in culture.

BACKGROUND The neurosteroids dehydroepiandrosterone (DHEA) and its sulfated metabolite (DHEAS) have been reported to possess neuroprotective as well as anti-tumoral activity in vitro and in vivo. OBJECTIVES To compare the effect of the two neurohormones on cell viability in primary whole-brain fetal mouse culture and isolated neuronal culture, as well as in a human neuroblastoma cell line (SK-N-SH). METHODS Cell viability and cell proliferation were determined with the neutral red and 3H-thymidine uptake methods. Apoptosis in propidium iodide-stained neuroblastoma cells was determined using flow cytometry. RESULTS DHEA (1 nM-10 microM) decreased the viability of selected primary neuronal cells (33-95% after 24 and 72 hours) but not of whole-brain cultured cells (neuron + glia). DHEAS did not significantly modify cell viability in either primary culture. In a human neuroblastoma cell line, DHEA (1 nM-1 microM) decreased 3H-thymidine uptake (30-60%) and cell viability (23-52%) after 24 hours. DHEAS did not significantly modify, or only slightly stimulated, cell viability and uptake of 3H-thymidine (132% of controls). The combination of DHEA and DHEAS neutralized the toxic effect of DHEA in both primary neuronal culture and neuroblastoma cell line. Flow cytometric analysis of DNA fragmentation in neuroblastoma cells treated with 100 nM DHEA/DHEAS for 24 hours showed an increase in apoptotic events (31.9% and 26.3%, respectively, vs. control 2.54%). CONCLUSIONS Our results do not confirm a neuroprotective role for DHEA and suggest that DHEA and DHEAS have a differential role; DHEA possesses a neurotoxic (expressed only in isolated neurons) and anti-proliferative effect; DHEAS demonstrates only a slight neuroprotective effect.