(A) Observation of ultrastructure of mitochondria by transmission electron microscopy (n=3). (B) The proportion of mitochondria with altered ultrastructure under different experimental conditions (n=3), significant differences (P<0.05) were observed among a–c. (C) Detection of intracellular ATP levels (n=3), significant differences (P<0.05) were observed among a–d. (D) Detection of intracellular NAD+ levels (n=3), significant differences (P<0.05) were observed among a–c. (E) Western blot analysis of PGC-1α and NRF1 expression in BMSCs (n=3). (F) Analysis of relative expression of PGC-1α (n=3), significant differences (P<0.05) were observed among a–d. (G) Analysis of relative expression of NRF1 (n=3), significant differences (P<0.05) were observed among a–d. (H,I) Detection of mitochondrial membrane potential using a mitochondrial membrane potential assay kit with TMRE (n=3). All the experiments were repeated at least thrice (n≥3), significant differences (P<0.05) were observed among a–c. Data were presented as means ± SD. P<0.05 by one-way ANOVA with Tukey’s post hoc test (three or more groups). Abbreviations: COX IV, cytochrome c oxidase IV; 3-TYP, 3-(1H-1,2,3-triazol-4-yl) pyridine.