Fig 2.

 Effect of celastrol on the cellular viability of undifferentiated neuronal cells. (A) Microscopic analysis using propidium iodide (PI) exclusion methodology revealed that celastrol at 3 μM triggered cell death in undifferentiated human (SH-SY5Y) and rodent (NG108-15) neurons (indicated by arrows). Control, cells without treatment; dimethyl sulfoxide (DMSO), vehicle control for celastrol; Ce, celastrol dissolved in DMSO vehicle. (B) A dose-response analysis indicated that the threshold at which neuronal viability was affected was 1 μM for undifferentiated human neurons and 1.5 μM for undifferentiated rodent neurons