Mitochondrial and contractile function improvement induced by aerobic training in hypertensive rat myocardium

GODOY COTO J.; PEREYRA E,; CAVALLI F.,; CALDIZ CI; YEVES A.M.,; ENNIS I.L.

Berlin

Congreso; XXIV World Congress International Society for Heart Research (ISHR); 2022

International Society of Heart Research

Mitochondrial and contractile function improvement induced byaerobic training in hypertensive rat myocardiumJoshua Godoy Coto, Erica Pereyra, Fiorella Cavalli, Claudia I. Caldiz,Alejandra M. Yeves, Irene L. EnnisCardiovascular Research Center, UNLP – CONICET, La Plata, ArgentinaIntroductionEssential hypertension pathologically remodels the heart, with declinedcontractility, oxidative stress, and mitochondrial dysfunction. Long-termexercise promotes cardioprotection, at least due to heart remodeling andredox rebalancing.ObjectiveTo assess the aerobic training beneficial adaptations in heart functionand myocardial mitochondria in spontaneously hypertensive rats (SHR).Methods3-month-old male SHR were randomized to sedentary (S) or trained (T)groups. The T group was submitted to an 8-week (5 days/week) swimmingprotocol. Blood pressure and echocardiography measurements wererecorded before and after the training period. Hearts were destined fortransmission electron microscopy imaging, RT-PCR analysis, Western Blot,enzymatic activity, or mitochondrial isolation. Results are presented asmean ± SEM (n) and considered statistically different when p b 0.05.Otherwise, the p-value is stated. Animal Welfare Committee of ourestablishment approved animal handling protocols.ResultsThe 8-week swimming training trended to attenuate blood pressure rise(mmHg, S: 26.01 ± 7.32 (11), T: 7.43 ± 7.45 (11), p =0.09) and improvedmid-ventricular shortening (% (n=17), S0: 23.45 ± 1.27, SF: 26.13 ± 1.04,T0: 23.16 ± 1.29, TF: 28.98 ± 0.64). Regarding to redox balance, chronicexercise improved catalase activity (k/g, S: 223.2 ± 44.9, T: 460.7 ± 78.5).Even though it did not modify the mitochondrial morphology assessed bycross-sectional area and aspect ratio; a partial recovery of the mitochondriasarcomerearray was evidenced (mitochondrial clusters/photo, S: 8.10 ±0.73 (5), T: 5.74 ± 1.34 (5), p=0.16). Moreover, exercise training modifiedthe mitochondrial dynamics (% vs S, (n=6)): mtDNA/nDNA: 129.7 ± 14.0