Late Breaking Abstract - Effects of preventive exercise in monocrotaline rat model with pulmonary hypertension

Abstract

In patients with pulmonary hypertension(PH), right ventricular failure(RVF) is the main determinant of prognosis and a common cause of death. PH leads to compensated hypertrophy that progresses to decompensated RVF. RVF is accompanied by changes in the right ventricle(RV) and extracellular matrix(ECM). Preventive exercise has been shown to be a therapeutic approach in PH. We evaluated the influence of preventive exercise in ECM in the RV compensated hypertrophy in PH. We used male Wistar rats divided into 4 groups(n=8): Sedentary control(SC); Training control(TC); Sedentary PH(SPH); and Training PH(TPH). The rats performed the exercises for 13 weeks. PH was induced by monocrotaline(60mg/kg) during the 10th week of training, and the control rats received a saline solution. At the end of the 13th week, echocardiogram were performed, and the rats were euthanized. RV hypertrophy was assessed through histomorphometric analysis. Gene expression using RT-qPCR: colIa1(collagen type I alpha 1 chain); colIa2(collagen type I alpha 2 chain); coll3a1(collagen type III alpha 1 chain);and Mmp2 and 9(matrix metalloproteinase 2 and 9). Collagen content was assessed through picrosirius red. Our results showed increases in cardiomyocyte sectional area(SC vs. SPH,p=0.0001), peak flow velocity(SC vs. SPH,p=0.001), and gene expression of the colla1(SC vs. SPH,p=0.007). The preventive exercise normalized the peak flow velocity(SHP vs. TPH, p=0.001) and decreased the area of the cardiomyocytes(SHP vs. TPH,p=0.001). This occurred without changes in the ECM. Preventive exercise exerts a cardioprotective effect in compensated hypertrophy in monocrotaline rat model with PH(function and hypertrophy), without alterations in ECM.