Fig. 4

Effect of mitochondrial dysfunction in senescent PD-MSCs during long-term cultivation. a Representative confocal images showed mitochondrial superoxide levels (MitoSox Red) and mitochondrial content (MitoTracker Green) in early passage, late passage, and hTERT+ PD-MSCs (magnification, × 200). b The ROS levels of early and late passage PD-MSCs were measured with the fluorescent dyes DCFDA. c The mitochondrial mass of early and late passage PD-MSCs was analyzed by using the NAO, respectively. d The mitochondrial membrane potential of early and late passage PD-MSCs was detected by JC-1 fluorescent dye which is measured as the ratio of the J-aggregated (red) to the JC-1 monomeric (green) forms. e Relative ATP levels of early and late passage PD-MSCs were analyzed by ATP production assay kit. f XF analyses revealed the oxygen consumption rates of fatty acid, glucose, and glutamine pathways in early and late passage PD-MSCs. The data were representative of three independent experiments and expressed as means ± S.D. An asterisk indicates P < 0.05 versus early passage