Study of morphological and functional cardiac adaptations promoted by the pharmacological approach in association with aerobic physical training in hypertensive rats

The most common systemic arterial hypertension (HBP) treatment involves a pharmacological approach based mainly on the inhibition of the renin-angiotensin-aldosterone system (RAAS). However, other approaches have been used with excellent results, such as the prescription of regular physical exercises, mainly aerobic, often as adjunctive therapy to pharmacological treatment. However, although the literature shows that the combination of treatments promotes greater blood pressure reductions (PA), we know little about the tissue and functional effects of the heart. Therefore, the main objective of the study was to investigate the effects of isolated and associated treatments of RAAS inhibition and aerobic physical training on hemodynamics, morphology and cardiac function in spontaneously hypertensive rats (SHR), as well as on the reactivity of the coronary bed and contractility of the left ventricle. For that, the thesis was divided in two studies; The first addressed the effects of hypertension on the aforementioned parameters, and the adaptations promoted by aerobic physical training; While in the second study we compared the effects of aerobic physical training and inhibition of prescribed RAAS alone or in combination. Male Wistar rats (N = 12) and SHR, 18 weeks of age (N = 24) were used. The animals were divided into three groups: group of normotensive Wistar rats (N = 12), SHR (N = 12) group treated with vehicle (water) and SHR group (N = 12) treated with Enalapril maleate (10 mg / Kg / day-1) for 10 weeks. Half of each group underwent aerobic physical training by swimming for 10 weeks. All groups were submitted to two experimental protocols; The morphofunctional evaluation of the left ventricle using conventional two-dimensional echocardiography performed on live animals; And the study of coronary bed reactivity and left ventricular contractility in isolated hearts by the Langendorff technique. Our results showed that the association of physical training with Enalapril maleate promoted the most significant reductions in BP. The results of the echocardiographic evaluation in the live animals showed that the SHR had important morphological alterations when compared with the normotensive ones. Physical training had little effect on these alterations, unlike Enalapril maleate that modified several parameters evaluated. In turn, results from the Langendorff technique in isolated hearts showed that SHR presented higher reactivity to coronary flow and lower intraventricular systolic pressure. Physical training and Enalapril maleate increased intraventricular systolic pressure, and when compared, physical training presented higher values. The combination of the treatments did not potentiate the results. In conclusion, in the echocardiographic examination the treatment with Enalapril maleate presented more prominent results, whereas the effects of the physical training on the heart were better evidenced by the technique of Langendorff. The combination of the two treatments had no additional effects on the parameters evaluated. (AU)