Figure 2.

6-hydroxydopamine (6-OHDA) induces neurotoxicity. 6-OHDA caused cytotoxicity in both Neuro-2a cells (A) and SH-SY5Y cells (B) in a concentration dependent manner, shown by the 6-OHDA dose-response curves. Cells were treated with 6-OHDA at different concentrations for 24 or 48 hr, and the cell viability was measured by MTT [3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide] reduction assay. 6-OHDA EC₅₀ = 111 µM for 24 hr incubation and 109 µM for 48 hr incubation in the Neuro-2a cells; 6-OHDA EC₅₀ = 118 µM for 24 hr incubation and 107 µM for 48 hr incubation in the SH-SY5Y cells. Data are shown as mean ± SEM (n = 4–6).