ascorbic-acid and 25-hydroxycholesterol

PC12 cells induced to differentiate with nerve growth factor were used to study the neurotoxicity of 25-OH-cholesterol. This agent induced a dose- and time-dependent cell death in neuronal PC12 cells. Cells treated with this agent showed condensed nuclei, a morphology similar to that of cells dying of programmed cell death. However, agents known to prevent neuronal programmed cell death (cyclic AMP, KCl, aurintricarboxylic acid, and cycloheximide) failed to prevent the 25-OH-cholesterol-mediated cytotoxicity. On the other hand, cell death induced by 25-OH-cholesterol was prevented by treatment with vitamin E and methyl-beta-cyclodextrin. In contrast to observations made in other cell types, whole-cell patch clamp recording of neuronal PC12 cells revealed that treatment with 25-OH-cholesterol did not significantly alter calcium influx through voltage-dependent channels. These results provide the first characterization of the toxicity of cholesterol oxides toward neuronal PC12 cells, which should be useful in future studies on the interactions between cholesterol oxides and cells from the nervous system.

Topics: Animals; Apoptosis; Ascorbic Acid; Aurintricarboxylic Acid; beta-Cyclodextrins; Blood; Calcium Channels; Cell Differentiation; Cyclic AMP; Cyclodextrins; Hydroxycholesterols; Nerve Growth Factors; PC12 Cells; Potassium Chloride; Rats; Vitamin E

Cultured rat cerebellar granule cells were used to determine the potential neurotoxicity of cholesterol oxides. The cholesterol oxides tested included: 7-beta-OH-, 7-keto-, 19-OH-, 22(R)-OH-, 22(S)-OH- and 25-OH- cholesterol. Among them, 7-beta-OH- and 7-keto-cholesterol were the most efficacious in causing neuronal death such that 20 microg/ml (50 microM) of these agents killed more than 80% of cells in 2 days. 7-beta-OH-cholesterol at this concentration killed 50% of cells in approximately 7 h. A number of pharmacological agents were tested for their abilities to prevent neuronal death induced by cholesterol oxides. Among them, aurintricarboxylic acid, vitamin E and methyl-beta-cyclodextrin were able to prevent cholesterol oxide-induced neurotoxicity in a dose-dependent manner. These results suggest that, in addition to causing pathological changes in cells directly involved in atherosclerosis, cholesterol oxides may induce toxicity in neurons of the central nervous system.

Topics: Animals; Ascorbic Acid; Aurintricarboxylic Acid; beta-Cyclodextrins; Cell Death; Cells, Cultured; Cerebellum; Cyclic AMP; Cyclodextrins; Cycloheximide; Drug Interactions; Hydroxycholesterols; Neurons; Protein Synthesis Inhibitors; Rats; Rats, Sprague-Dawley; Vitamin E