Resveratrol activation of SIRT1/MFN2 can improve mitochondria function, alleviating doxorubicin‐induced myocardial injury

Figure 1. The effects of doxorubicin on the general vital sign resulted in a loss of weight and an increase in aortic blood pressure. (a) Adult male C57BL/6J mice (10 weeks old) were randomly divided into a control group (CON) and a doxorubicin group (DOX) which was injected with doxorubicin (7.5 mg/kg, twice every other day, intraperitoneally). (b) Weight change was calculated as a percentage change in weight compared with the baseline. (c, d) Blood pressure and heart rate in the two groups; (e, f) blood pressure and heart rate were observed in the doxorubicin group compared with the baseline (n = 7–10). Data are mean ± SD; *p < 0.05, **p < 0.01, ****p < 0.0001. DBP, diastolic blood pressure; HR, heart rate; MBP, mean blood pressure; SBP, systolic blood pressure.

Figure 2. Doxorubicin causes structural and electrical remodeling of the heart. (a) Representative figures for M‐mode of echocardiographic images in the two groups; (b) typical body surface ECGs in the two groups; (c–f) analysis results of left ventricular echocardiographic parameters in each group; (g–h) Results of ECG parameters between groups. (i, j) The representative figures for mapping and the results for conduction velocity. (k) Representative images of HE staining, scale bar, 20 and 50 µm. Data are mean ± SD; n = 7–9. *p < 0.05, **p < 0.01, ***p < 0.001. CON, control group; DOX, doxorubicin group; LVIDd, left ventricular internal dimension end‐diastolic; LVIDs, left ventricular internal dimensions end‐systolic.

Figure 3. Doxorubicin impaired cardiomyocyte mitochondrial function and disrupted mitochondrial homeostasis. (a) Representative confocal microscopy images of mitochondrial membrane potential fluorescence staining and its statistics; the ratio of red/green fluorescence reflects the membrane potential changes. Scale bar, 50 µm. n = 3 independent experiments. (b) Transmission electron microscopy images of mitochondria in mice ventricular cardiomyocyte. Red arrows show normal mitochondrial morphology; white arrows show damaged mitochondrial morphology. N = 3. Scale bar, 200 and 500 nm; (c) Expression of α‐SMA, MFN2, SIRT1, and caspases3 protein in mice ventricular tissues among two groups (n = 5–7). (d–g) Quantification of α‐SMA, MFN2, SIRT1, and caspases3 in (c). Data are mean ± SD. *p < 0.05, **p < 0.01, ****p < 0.0001. α‐SMA, α‐smooth muscle actin; CON, control group; DOX, doxorubicin group; MFN2, Mitofusin2; PBS, phosphate‐buffered saline, the control group in H9c2 cells; SIRT1, Sirtuin1.

Figure 4. Doxorubicin increased oxidative stress in cardiomyocytes which could be reversed by resveratrol. (a) Representative DCFH‐DA fluorescent images in H9c2 cells treated with different concentrations of doxorubicin. Scale bar, 200 µm. (b) DCFH‐DA fluorescence intensity quantification. (c) Representative DCFH‐DA fluorescent images in each group. Scale bar, 100 µm. Quantification of DCFH‐DA in (d). (e) Expression of Mn‐SOD protein among the three groups. n = 3, for independent experiments. (f) Quantification of Mn‐SOD protein expression in (e). *p < 0.05, **p < 0.01, ****p < 0.0001. Data are mean ± SD. DOX, doxorubicin group; DOX + RES, doxorubicin + resveratrol group; MnSOD, manganese superoxide dismutase; PBS, phosphate‐buffered saline, the control group in H9c2 cells.

Figure 5. Resveratrol promoted the expression of SIRT1 and MFN2 in cardiomyocytes, which improved mitochondrial homeostasis and reversed doxorubicin damage. (a) Representative confocal microscopy images of mitochondrial membrane potential fluorescence staining and its statistics; the ratio of red/green fluorescence reflects the membrane potential changes. Scale bar, 50 µm. n = 3. (b) Quantification of DCFH‐DA in (a). (c–e) Representative western blot results of expression of SIRT1, MFN2, and Caspases3 protein among the three groups. Data are mean ± SD. *p < 0.05, **p < 0.01, ***p < 0.001. DOX, doxorubicin group; DOX + RES, doxorubicin + resveratrol group; MFN2, Mitofusin2; PBS, control group in H9c2 cells; SIRT1, Sirtuin1.