Mitochondrial membrane potential (MMP) of the PC12 cells measured by JC-1 as an indicator of mitochondrial function. (A) Red fluorescence intensity (excitation, 550 nm; emission, 600 nm) and green fluorescence intensity (excitation, 485 nm; emission, 535 nm) were determined by using a fluorescence plate reader. (B) Confocal images show JC-1 fluorescence (60 × 3.5). Data are reported as a percentage of the control. * p < 0.05, and ** p <0.01.