The Roles of FGF21 and ALCAT1 in Aerobic Exercise‐Induced Cardioprotection of Postmyocardial Infarction Mice

Figures

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  Figure 1. The protective of aerobic exercise on the MI heart in WT and fgf21−/− mice. (a) The myocardial infarct size was measured with Masson's trichrome staining. The images show that the fibrosis marker was stained in blue, whereas cardiac muscle fibers in red and nuclei in dark brown. Above: original magnification ×4; middle: original magnification ×10; below: original magnification ×20. Scale bar: 10 μm. (b) Quantification of collagen volume of fraction (CVF%). (c) Echocardiography. (d) Left ventricular end diastolic diameter (LVIDd) and left ventricular systolic diameter systole (LVIDs). (e) Left ventricular ejection fraction (EF) and left ventricular short axis (FS). CVF: collagen volume fraction; EF: ejection fraction%; FS: fractional shortening%; LVIDd: left ventricular internal diameter diastole; LVIDs: left ventricular internal diameter systole. S: sham group; ME: MI + aerobic exercise group. Data presented are means ± SD. One-way ANOVA with post hoc LSD multiple-comparison test. ∗p < 0.05, ∗∗p < 0.01.

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  Figure 2. Aerobic exercise significantly inhibited oxidative stress and ER stress-induced apoptosis and activated the FGF21/FGFR1/PI3K/AKT pathway. (a–c) Western blotting images and their densitometric quantitative analysis of ALCAT1, SOD2, p-PI3K/t-PI3K ratio, p-AKT/t-AKT ratio, p-IRE1α/t-IRE1α ratio, p-JNK/t-JNK ratio, GRP78, CHOP, Bax/Bcl-2 ratio, and c-caspase3. (d) TUNEL staining: TUNEL-positive granules in red and DAPI in blue. Original magnification ×10. Scale bar: 200 px. (e) TUNEL-positive cells count. S: sham group; ME: MI + aerobic exercise group. Data presented are means ± SD. One-way ANOVA with post hoc LSD multiple-comparison test. ∗p < 0.05, ∗∗p < 0.01.

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  Figure 3. Aerobic exercise training significantly inhibited oxidative stress and ER stress-induced apoptosis partly via FGF21. (a, b) Western blotting images showed the phosphorylation levels of IRE1α and JNK, and the protein levels of IRE1α, JNK, GRP78, CHOP, Bax/Bcl-2 ratio, c-caspase3, SOD2, and ALCAT1. (c, d) TUNEL staining: TUNEL-positive granules in red and DAPI in blue. Original magnification ×10. (e) MDA content in the myocardium. (f) Enzyme activity of CAT in the myocardium. Scale bar: 200 px. ME: MI + aerobic exercise group. Data presented are means ± SD. One-way ANOVA. ∗p < 0.05, ∗∗p < 0.01.

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  Figure 4. Aerobic exercise and knockout alcat1 reduced cardiac oxidative stress and apoptosis in MI mice. (a) Myocardial infarct size was measured with Masson's trichrome staining. The images showed that the fibrosis marker was stained in blue, whereas cardiac muscle fibers in red and nuclei in dark brown. Scale bar: 200 μm. Quantification of collagen volume of fraction (CVF%). (b) Echocardiography. (c) Left ventricular end diastolic diameter (LVIDd). (d) Left ventricular systolic diameter systole (LVIDs). (e) Left ventricular ejection fraction (EF). (f) Left ventricular short axis (FS). (g) Protein expression levels of ALCAT1. (h) MDA content in the myocardium. (i) GSH content in the myocardium. (j) GSH-Px activity in the myocardium. (k) CAT activity in the myocardium. (l) T-SOD activity in the myocardium. (m) TUNEL staining: TUNEL-positive granules in red and DAPI in blue. (n) TUNEL-positive cells count. (o) Protein expression levels of the Bax/Bcl-2 ratio. CVF: collagen volume fraction; EF: ejection fraction%; FS: fractional shortening%; LVIDd; left ventricular internal diameter diastole; LVIDs: left ventricular internal diameter systole. S: sham group; ME: MI + aerobic exercise group.…

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  Figure 5. AICAR or rhFGF21 reduced the oxidative stress and ER stress-induced apoptosis by H2O2 in H9C2 cells. (a) T-SOD activity in H9C2 cells. (b) MDA in H9C2 cells. (c–f) Western blotting images and their densitometric quantitative analysis of ALCAT1, p-PI3K/t-PI3K ratio, p-AKT/t-AKT ratio, p-IRE1α/t-IRE1α ratio, p-JNK/t-JNK ratio, GRP78, CHOP, Bax/Bcl-2 ratio, and c-caspase3. (g) TUNEL staining: TUNEL-positive granules in red and DAPI in blue. (h) TUNEL-positive cells count. Data presented are means ± SD. One-way ANOVA with post hoc LSD multiple-comparison test. ∗p < 0.05, ∗∗p < 0.01.

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  Figure 6. PI3K inhibitor inhibited the FGF21 overexpression-mediated oxidative stress and antiapoptotic effect on ER stress injury. (a–c) Western blotting images and their densitometric quantitative analysis of SOD2, p-AKT/t-AKT ratio, p-IRE1α/t-IRE1α ratio, p-JNK/t-JNK ratio, GRP78, CHOP, Bax/Bcl-2 ratio, and c-caspase3. Data presented are means ± SD. One-way ANOVA with post hoc LSD multiple-comparison test. ∗p < 0.05, ∗∗p < 0.01.

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  Figure 7. FGF21 inhibited oxidative stress and apoptosis induced by ALCAT1 overexpression through the PI3K-AKT pathway. SOD2, p-PI3K, p-AKT/t-AKT ratio, Bax/Bcl-2 ratio, and c-caspase3 protein levels after rhFGF21 or/and LY294002 intervention in H9C2 cells transfected with lentivirus containing alcat1 gene. Data presented are means ± SD. One-way ANOVA with post hoc LSD multiple-comparison test. ∗p < 0.05, ∗∗p < 0.01.

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  Figure 8. Possible mechanism of aerobic exercise in improving cardiac function in myocardial infarction mice.