Figure 4.

Mitochondrial activity of PC12 cells after pre-incubation of XF (0.5 or 1 µg/mL) in cell culture flasks for at least 48 h, which were treated with 3-NP (2.5, 5, 10 and 15 mM) with the absence or presence of very low concentrations of XF (0.5 and 1 µg/mL) for 8 h (A) and 24 h (B). The mitochondrial activity of cells was measured using a 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT) assay. The data represent the mean ± SD of cell viability in five independent experiments. Significantly higher from the corresponding 3-NP treatments group at * p < 0.05 or ** p < 0.005 and significantly lower from the corresponding 3-NP treatments at ^ p < 0.05 or ^^ p < 0.005.