Early moderate exercise benefits myocardial infarction healing via improvement of inflammation and ventricular remodelling in rats

Figures

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  Figure 1. Early moderate exercise reduces infarct size and cardiomyocyte apoptosis and improves cardiac function in myocardial infarct (MI). (I) Schematics of the training programme. (II) Masson's trichrome staining showed that early moderate exercise reduced infarct size. n = 6‐8. (III) Echocardiography revealed that early moderate exercise improved the ejection fraction (a) and fractional shortening (b). n = 5‐8. (IV‐VI) TUNEL staining demonstrated that early moderate exercise attenuated cardiomyocyte apoptosis. (a) Sedentary heart. (b) Moderate exercise heart. (c) Semiquantification of (a) and (b). n = 4‐5. For early moderate exercise, the animals were trained for two weeks beginning one day after MI

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  Figure 2. Early moderate exercise improves angiogenesis, fibrosis and ventricular remodelling in myocardial infarct (MI). (I) Immunohistochemical staining for vWF showed that blood vessel density in the infarct zone and border zone in early moderate exercise hearts was significantly higher than those in sedentary hearts. (a) Semiquantification of (b) and (c). (b) Infarct zone. (c) Border zone. n = 6‐8. (II) Masson's trichrome staining documented that the collagen area of the infarct zone in early moderate exercise hearts was significantly smaller than that in sedentary hearts. (a) Semiquantification of (b) and (c). (b) Sedentary heart. (c) Early moderate exercise heart. n = 9 per group. (III) Masson's trichrome staining revealed that the TIM in early moderate exercise hearts was significantly larger than that in sedentary hearts, whereas the difference in the WTBZ between early moderate exercise hearts and sedentary hearts was not significant. (a) Schematics of TIM and WTBZ. (b) Semiquantification of TIM. (c) Semiquantification of WTBZ. n = 6‐9 per group. (IV) WAG immunofluorescence staining demonstrated that the cardiomyocyte cross‐sectional area of both the border zone and the remote…

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  Figure 3. Early moderate exercise increases the number of cardiac telocytes in the border zone but not in the infarct zone. (I) Immunofluorescence staining for PDGFRα+/CD34+ revealed that the density of CTs in the early moderate exercise group was slightly increased compared with that in the sedentary group; however, the difference was not statistically significant. (II) Immunofluorescence staining for PDGFRα+/CD34+ revealed that, in the border zone, the density of CTs in the early moderate exercise group was significantly increased compared with that in the sedentary group. (a1‐4) Sedentary heart. (b1‐4) Early moderate exercise heart. (c) Semiquantification of (I) and (II). n = 5 per group. The animals were trained on early moderate exercise for two weeks beginning one day after MI

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  Figure 4. Early moderate exercise inhibits the inflammatory response in infarcted myocardium. (I) Immunofluorescence staining for CD45+ leucocytes revealed that the density of CD45+ leucocyte infiltration in the infarct zone was significantly decreased in early moderate exercise hearts compared with sedentary hearts. (II) Immunofluorescence staining for CD68+ macrophages (M1 macrophages) demonstrated that the density of M1 macrophages in the infarct zone was significantly decreased in early moderate exercise hearts compared with sedentary hearts. (III) Immunofluorescence staining for CD206+ macrophages (M2) showed that the density of CD206+ macrophages in the infarct zone was increased significantly in early moderate exercise hearts compared with sedentary hearts. (IV) Immunofluorescence staining for CD163+ macrophages (M2) showed that the density of CD163+ macrophages in the infarct zone was increased significantly in early moderate exercise hearts compared with sedentary hearts. (a) Semiquantification of (b) and (c). (b) Sedentary heart. (c) Early moderate exercise heart. n = 5 per group. The animals were trained on early moderate exercise for two weeks beginning one day after MI

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  Figure 5. Inhibition of the TGFB1 regulatory network in the infarct zone of the early moderate exercise‐trained heart. (I) The upstream analysis of the integrated ingenuity pathway analysis between miRNAs and mRNAs in the infarct zone predicted that compared with the sedentary MI heart, the primary upstream molecule was TGFB1, which was inhibited in the infarct zone of the early moderate exercise MI heart (P‐value = 1.78E‐08; z‐score = −2.266). The inhibition of 10 genes (TGFB1, FN1, MAPK14, SP1, SP3, ESR1, SMAD4, EGR1, CREBBP and SMAD3) and the activation of 3 genes (HDAC2, TP73 and SMAD7) played a role in the inhibition of the TGFB1 regulatory network. The network displays the regulatory relationship of these 13 genes in which SP1, SMAD4 and SMAD3, the direct downstream genes that are regulated by TGFB1, were inhibited, whereas SMAD7, the inhibitor of the TGFB1 pathway, was activated. In addition, the indirect downstream genes, FN1, MAPK14, SP3, ESR1, EGR1 and CREBBP, were predicted to be inhibited, whereas TP73 was activated. (II) The qPCR quantifications of the expression levels of selected genes included in the TGFB1 network. The animals were trained on early moderate exercise for two…

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  Figure 6. Inhibition of leucocyte activation played a role in the early moderate exercise‐mediated improvement of inflammation. (I) The integrated ingenuity pathway analysis between miRNAs and mRNAs predicted that the activation of leucocytes in the infarct zone was decreased (P‐value = 3.51E‐04; z‐score = −2.209) in the early moderate exercise MI heart compared with the sedentary MI heart. The regulatory network demonstrates that 27 molecules (20 down‐regulated genes, 3 up‐regulated gene and 4 up‐regulated miRNAs) were included in the regulatory network for the decreased activation of leucocytes. The directive inhibition relationship, which included miR‐125b‐5p for ITGA1, FCGR2A for CCL2 and KLF2 for CCL2, was shown to be associated with the inhibition of leucocyte activation. (II) The qPCR quantifications of the expression levels of selected genes included in the decreased activation of the leucocyte network and decreased leucocyte migration network (Figure 7). (a) Selected genes. (b) Selected miRNAs. The animals were trained on the early moderate exercise for two weeks beginning one day after MI. n = 3 per group. *P < .05 vs the sedentary group

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  Figure 7. Inhibition of leucocyte migration was included in early moderate exercise‐mediated improvement of inflammation. The integrated ingenuity pathway analysis between miRNAs and mRNAs predicted that leucocyte migration in the infarct zone would be decreased in the early moderate exercise myocardial infarct (MI) heart compared with the sedentary MI heart (P‐value = 2.67E‐04; z‐score = −2.912). The regulatory network shows that 36 molecules (30 down‐regulated genes, 5 up‐regulated genes and 1 up‐regulated miRNA) were included in the regulatory network for decreased leucocyte migration. The directive inhibition relationship, which included miR‐125b‐5p for VTCN1 and VDR and KLF2 for THBS1 and CCL2, was revealed to be related to the inhibition of leucocyte migration. The animals were trained on the early moderate exercise for two weeks beginning one day after MI. n = 3 per group