Fig. 2. Culture expansion of human mesenchymal stem cells (hMSCs) induces mitochondrial dysfunction.
a Mitochondrial morphology was altered during culture expansion of hMSCs. b Increased mitochondrial mass and c loss of mitochondrial membrane intensity were observed in hMSCs at late passage, both determined by flow cytometry. d Mitochondrial reactive oxygen species (ROS) and e total ROS were also increased during in vitro culture expansion of hMSCs. f Electron transport chain complex I (ETC-I) activity was reduced in late passage of hMSCs compared to cells at early passage. g Culture expansion induced loss of hMSC mitophagy, as well as h mitochondrial fusion and fission dynamics determined by mRNA levels. i Genes involved in mitochondrial biogenesis were decreased during culture expansion of hMSCs. Scale bar: 50 µm. Ng negative control. Biological replicates (n): n = 3. *p < 0.05; **p < 0.01; ***p < 0.001.