Physical Training as a Blood Pressure Reducer and a Remodeler of Cardiac Fibers in Spontaneously Hypertensive Rats (SHR)
Mariana Molinar Mauad Cintra
Department of General Pathology, Federal University of Triângulo Mineiro (UFTM), Uberaba, Minas Gerais, Brazil.
Matheus Ribeiro Bizuti *
Department of Medicine, Federal University of Fronteira Sul (UFFS), Chapecó, Santa Catarina, Brazil.
Octávio Barbosa Neto
Department of Biological Sciences, Federal University of Triângulo Mineiro (UFTM), Uberaba, Minas Gerais, Brazil.
Marlene Antônia dos Reis
Department of General Pathology, Federal University of Triângulo Mineiro (UFTM), Uberaba, Minas Gerais, Brazil.
Lenaldo Branco Rocha
Department of General Pathology, Federal University of Triângulo Mineiro (UFTM), Uberaba, Minas Gerais, Brazil.
Débora Tavares de Resende e Silva
Department of Anatomy, Federal University of Fronteira Sul (UFFS), Chapecó, Santa Catarina, Brazil.
*Author to whom correspondence should be addressed.
Abstract
Background: Hypertension is the most prevalent of all cardiovascular diseases, reaching target organs such as the heart. Blood pressure control is critical for preventing organ damage induced by hypertension.
Objective: To analyze blood pressure, heart rate, left ventricular thickness, the percentage of cardiac fibrosis and the percentage of type III collagen in Spontaneously Hypertensive Rats (SHR) submitted to swimming physical training.
Methods: The experimental groups were composed of male Wistar Kyoto (WKY) rats (309-311g), which were divided into: 1) Normotensive Sedentary group (SN) (n = 6); 2) Trained Normotensive group (TN) (n = 6); 3) Sedentary Hypertensive group (SH) (n = 6); 4) Trained Hypertensive group (TH) (n = 6). After the end of the protocol, the animals were initially anesthetized to measure blood pressure.
Results: Physical training was responsible for decreasing blood pressure (F = 16,968; p <0.001) and heart rate (F = 10.710; p = 0.004) in the trained groups (normotensive and hypertensive). Moreover, training was responsible for providing an increase in the thickness of the left ventricle (F = 7,254; p = 0.014) and a reduction in the percentage of cardiac fibrosis (F = 16,081; p <0.001). Furthermore, it was observed that the trained group had lower values of type III collagen (F = 13,166; p = 0.002).
Conclusions: Physical swimming training triggered a decrease in blood pressure, heart rate, the percentage of fibrosis and the percentage of type III collagen. In addition, there was also a cardiac remodeling due to the increase in left ventricular hypertrophy.
Keywords: Hypertension, exercise, fibrosis, extracellular matrix, swimming