Exercise Improves Cardiac Dysfunction in D-Galactose-Treated Rats by Regulation of IGF-1-Humanin Pathway

Introduction: Humanin, a mitochondrial-derived peptide, decreases in the elderly. This study evaluated the effects of concurrent moderate-intensity endurance training (MIET) or high-intensity interval training (HIIT) with D-galactose injection on cardiac function, and the serum and heart levels of humanin and IGF-1 in Wistar male rats. Methods: Left ventricular systolic pressure (LVSP), left ventricular end diastolic pressure (LVEDP), ±maxdp/dt, contractility index (CI) and, Tau were monitored by PowerLab system in CTL, CTL + MIET, CTL + HIIT, D-gal, D-gal + MIET, and D-gal + HIIT groups. The histopathological score, fibrosis, and humanin and IGF-1 levels were measured with hematoxylin & eosin, Masson's trichrome, and enzyme-linked immunosorbent assay, respectively. Results: Histopathological score and heart fibrosis were reduced by HIIT and MIET in the D-gal group. LVSP, ±maxdp/dt, and CI were lower, while LVEDP and Tau were higher in the D-gal group than in the CTL group. MIET and HIIT alleviated the changes in LVSP, ±maxdp/dt, CI, LVEDP, and Tau. HIIT and MIET increased humanin levels in heart and serum of the D-gal group by modifying IGF-1 levels. Conclusion: The study suggests HIIT and MIET may improve cardiac function by regulating the IGF-1-humanin signaling pathway.