Differences in mitochondrial efficiency and heart function after different modes of exercise training in hypertension

Abstract

Abstract Physical exercise is often used for the cardioprotective purpose in hypertension. However, it's not clear whether the mitochondrial efficacy will depend on the intensity and mode of physical exercise. The aim of the work is to investigate the effect of different modes of exercise training on mitochondria function and cardyohemodynamic in hypertension. All experimental procedures were performed in accordance with the European Communities Council Directive of 24 November 1986 (86/609 /EEC). Six-month-old spontaneously hypertensive rats (SHR) and normotensive control–Wistar rats were randomly assigned to 2 different training modes: moderate (20 min) and enhanced (45 min). Swimming training was done five times per week for 5–6 weeks. The functional cardiohemodynamic indicators were registered via microcatheter and Millar Pressure-Volume System. Mitochondrial oxygen consumption registered by Oxygraph. Moderate exercise training mode in SHR had a positive effect on the respiratory chain of mitochondria, respiratory control increased by 25,3%, the mitochondrial membrane potential increased by 47,8%. Moderate exercise training mode protected mitochondrial permeability transition pore (MPTP) formation. The threshold of MPTP opening increased by 1.4 times and the sensitivity of MPTP to inductor Ca2+ decreased. It was shown that end-systolic and end-diastolic pressure of SHR was decreased by 23,8% and 32,7% respectively. Moderate exercise improves end-diastolic heart function in SHR by increasing dP/dtmin and reducing the end-diastolic myocardial stiffness in 8,3 times. Stroke volume increased in 3,3 times, stroke work decreased by 17.2%, which may indicate the heart work efficiency increased after moderate exercise training. The Frank-Starling mechanism efficiency after moderate exercise was increased by 3,7 times. After enhanced exercise mode we didn't observe a protected effect on heart mitochondria and heart function in SHR. The mitochondrial membrane potential didn't increase, mitochondrial respiration in states V2, V3, V4 were significantly decreased. In conclusion, we showed that a moderate mode of exercise in SHR rats increased mitochondrial efficiency and improved heart function. The enhanced mode of exercise was excessive for SHR which was confirmed by suppressing the mitochondrial respiration and end-diastolic function of the heart. Funding Acknowledgement Type of funding sources: None.