Fig. 4

Mitochondrial ROS production was measured using MitoSOX Red (mitochondria-targeted superoxide indicator). a Fibroblast nuclei were labelled with LMNB BFP (blue fluorescent protein) and stem cell mitochondria were labelled with Cox8a GFP. Only fibroblasts with a blue fluorescent nucleus were measured. The measured fibroblasts were divided into two groups: fibroblasts with obviously transferred mitochondria derived from MSCs; and fibroblasts without transferred mitochondria. b MitoSOX measurement was performed after 72-h treatment with stem cell supernatant or control cell supernatant. Data shown as mean ± SEM. *p < 0.05, ***p < 0.001. c Representative fluorescence images showing a transferred MSC mitochondrion (green) in a human fibroblast (blue nuclei). Mitochondrial MitoSOX fluorescence is shown (red). Scale bar represents 10 μm. mMSC mouse mesenchymal stem cell, MSC mesenchymal stem cell, NDUFS4 NADH dehydrogenase ubiquinone Fe-S protein 4, ROS reactive oxygen species, WT wild type (Colour figure online)