Hypoxia-preconditioned mesenchymal stem cell-derived exosomes attenuate myocardial ischemia/reperfusion injury by miR-29b-3p via PINK1/Parkin-mediated mitophagy

Figure 5 miR-29b-3p alleviates myocardial ischemia/reperfusion injury by inducing mitophagy. A: Mdivi-1 inhibited mitochondrial autophagy; B: Flow cytometric analysis of MitoSOX Red-stained myocardial cells; C and D: Representative flow cytometry plots showing the effects of different treatments on cell apoptosis (C) and quantitative analysis of apoptosis rate (D); E and F: Western blot assay showed the effect of PINK1 siRNA on the protein expression of PINK1, Parkin, Tim23, Tom20, and LC3 and quantitative analysis; G and H: Representative flow cytometry plots showing the effects of different treatments on cell apoptosis (G) and quantitative analysis of apoptosis rate (H); I and J: Mitochondrial oxidative stress detected by flow cytometry (I) and its quantitative analysis (J); K: Schematic diagram of animal model establishment; L: Evans blue and triphenyltetrazolium chloride double staining of hearts 28 days after different treatments. Blue represent non-ischemic areas. Red represents ischemic areas. White represents infarcted areas; M: Echocardiographic measurements of left ventricular end-diastolic diameter, left ventricular end-systolic diameter, ejection fraction, and fractional shortening in mice subjected to sham surgery, ischemia/reperfusion (I/R), I/R + microRNA (miR)-negative control, I/R + miR-29b-3p, I/R + AAV9-sh-negative control, I/R + AAV9-sh-PINK1, and I/R + AAV9-sh-PINK1 + miR-29b-3p from 2 days to 4 weeks post-myocardial I/R injury (n = 10). ^aP < 0.05, ^bP < 0.01, ^cP < 0.001, ^dP < 0.0001. Con: Control; DHE: Dihydroethidium; H/R: Hypoxia/reperfusion; I/R: Ischemia/reperfusion; LVEDd: Left ventricular end-diastolic diameter; LVESd: Left ventricular end-systolic diameter; MFI: Mean fluorescent intensity; miR: MicroRNA; NC: Negative control; NS: Not significant; PI: Propidium iodide.