Liraglutide alleviates diabetic cardiomyopathy in streptozotocin-induced diabetic rats by enhancing mitophagy mediated by the AMPK-Parkin signaling pathway

Figure 6 Liraglutide attenuates mitochondrial damage and cardiomyocytes apoptosis via AMPK-Parkin pathway mediated mitophagy in neonatal rat cardiomyocytes induced by high glucose + palmitic acid. A: Mito-SOX Red staining representing mitochondrial reactive oxygen species (mitoROS) levels in the four groups (scale bar: 25 μm); B: Quantification of mitoROS production as measured with mito-SOX Red staining in B; C: Representative fluorescence staining images of JC-1 aggregates (red) and JC-1 monomer (scale bar: 25 μm); D: Relative fluorescence intensity of aggregate/monomeric JC-1 in D; E: Representative images Mito Tracker Red of the four groups (scale bar = 25 μm as indicated in upper panel, scale bar = 5 μm as indicated in low panel); F: Quantification of the mitochondrial mean length (white double arrow); G: Transmission electron microscopic images showing mitochondria in cardiomyocytes. Normal mitochondria were denoted by white arrows, while the damaged mitochondria (edema, cristae rupture and vacuolized) were indicated by yellow arrows (scale bar: 1 µm); H and I: Fraction of swollen mitochondria and mitochondrial loss of cristae in the four groups; J and K: Representative and quantitative analysis images of cell terminal deoxynucleotidyl transferase mediated dUTP nick end labeling staining for the three groups (scale bar: 50 μm); L-N: Representative western blotting images of pro-caspase 3, cleaved caspase 3, cytosolic-cytochrome C and mytosolic-cytochrome C in the the four groups; O-Q: Quantification of the expression of the proteins including pro-caspase 3, cleaved caspase3, cytosolic-cytochrome C and mytosolic-cytochrome C in L, N and P; R: Representative colocalization images of lysosomes (LysoTracker Green) and mitochondria (Mito Tracker Red; scale bar: 10 µm); S: The percentage of cells with lysosome (LysoTracker Green) and mitochondria (MitoTracker Red) colocalization; T: Representative Western blotting images of LC3 I, LC3 II and Pakin in the four groups; U and V: Quantification of the expression of the proteins including LC3I, LC3II and Pakin in T. ^aP < 0.05; ^bP < 0.01; ^cP < 0.001. Con: Control group; HG: High glucose; PA: Palmitic acid.