Fig. 2.

Neuronal cell death induced by H-NCD.A, Time course of H-NCD. Primary cultured cortical neurons were exposed to 300 μm pravastatin for the indicated periods. B, Dose-dependent effect of neurotoxicity by HMG-CoA inhibitors (pravastatin, simbastatin, and lovastatin). Primary cultured cortical neurons were exposed to the indicated concentrations of pravastatin, simbastatin, and lovastatin for 72 hr. C, Dose-dependent effect of mevalonate to reverse H-NCD. Neurons were incubated with the indicated concentrations of mevalonate in the presence of 300 μm pravastatin. The live cell number was assayed by mitochondrial conversion to formazan as detected by the change of OD at 570 nm during the final 3 hr of culture, as described in Materials and Methods. Each point represents the mean ± SEM of triplicates. D, Morphological observations of H-NCD. Fluorescein diacetate propidium iodide staining 72 hr after addition. Top, Control;Middle, 300 μm pravastatin; andBottom, 0.03 mg/ml of mevalonate in the presence of 300 μm pravastatin. Fluorescein diacetate propidium iodide staining was described in Materials and Methods. The dead neurons were red-stained round cells, and the live neurons had a green–yellow cell body. The data shown was a representative of three independent experiments.