The neurotoxic effect of 24-hydroxycholesterol on SH-SY5Y human neuroblastoma cells

Neurodegenerative disorders are characterized by a massive loss of nerve cells. The neuronal cell death is accompanied by an increased cholesterol release and conversion of cholesterol into the polar metabolite, 24-hydroxycholesterol (24-OH-Chol), appears to be an important mechanism in the central nervous system for eliminating cholesterol from the brain. We tested the influence of 24-OH-Chol on SH-SY5Y human neuroblastoma cells by recording cell morphology, Trypan blue exclusion, LDH-release into the culture medium, intracellular calcium and reactive oxygen species (ROS). The exposure of SH-SY5Y human neuroblastoma cells to 50 microM 24-OH-Chol led to a 90% loss in cell viability within 30 h, the LDH-release into the medium increased rapidly after 24 h, and after 24 to 30 h we found an elevation in intracellular calcium. These results show that, in a physiological concentration range, 24-OH-Chol damages neuronal cells, thus we speculate that this oxysterol may be involved in the etiology of neurodegenerative disease.