Fig. 1: MPP⁺ induces mitochondria-dependent apoptosis in PC12 cells.

PC12 cells were treated with various concentrations of MPP⁺ (0, 0.25, 0.5, 1, 2, 3, 4, and 5 mM) for 24 h (a) or at different time intervals (b), and the viability of PC12 cells was measured by the MTT assay. c The ATP Determination Kit was used to determine the concentration of ATP in PC12 cells treated with MPP⁺ (0, 0.5, 1, 2, 3, and 4 mM). d The mitochondrial membrane potential was measured by JC-1 staining. CCCP (10 µM) was used as the positive control. Scale bars: 20 μm. The fluorescence intensity ratio of red (JC-1 aggregates) to green (JC-1 monomers) fluorescence was used to represent the mitochondrial membrane potential. e The rhodamine 123 fluorescence intensity was detected by a microplate reader. f The expression of cleaved caspase-3 (C-Cas 3) and cleaved PARP (C-PARP) in whole-cell lysates was determined by western blot analysis. g, h The apoptosis rate was measured by flow cytometry using annexin V-FITC/PI staining. The data are expressed as the means ± S.D. (n = 3). ***P < 0.001 vs. the control group