Influência do Treinamento Aeróbio Preventivo na Remodelação Cardíaca de Ratos com Hipertensão Arterial Pulmonar

Abstract

Pulmonary Arterial Hypertension (PAH) is a chronic disease which causes overload to the right ventricle. The effect of preventive training on cardiac remodeling in this condition is still unknown. This study aimed to evaluate the influence of preventive training on hypertrophy, heart function and gene expression of calcium transport proteins in rats with monocrotaline-induced PAH. Thirty-two male Wistar rats were randomly divided into 4 groups: sedentary control (S); trained control (T); sedentary monocrotaline (SM); trained monocrotaline (TM). The preventive training protocol was performed on a treadmill for 13 weeks, 5 times/week. The first two weeks were adopted for adaptation to training with gradual increases in speed/time. The speed of the physical training from the third to tenth weeks was gradually increased from 0.9km/h to 1.1km/h for 60 minutes. Next, monocrotaline was applied (60mg/Kg) to induce PAH and lactate threshold analysis performed to determine the training speeds. The training speed of the TM group in the following two weeks was 0.8km/h-60min and the T=0.9km/h-60min; in the final two weeks both groups trained at the same speed and duration 0.9km/h, 60 min. Cardiac function was assessed through echocardiography, ventricular hypertrophy through histomorphometric analysis and gene expression through RT-qPCR. Right cardiac function assessed through the peak flow velocity was SM=75.5cm/s vs. TM=92.0cm/s (p=0.001) and ventricular hypertrophy was SM=106.4µm² vs. TM=77.7µm² (p=0.004). There was a decrease in the gene expression of ryanodine was S=1.12au vs. SM=0.60au (p=0.02) without alterations due to training. Thus, we conclude that prior physical training exerts a cardioprotective effect on the right ventricle in the monocrotaline rat model.