IJCS | Volume 31, Nº6, November / December 2018

DOI: 10.5935/2359-4802.20180060 585 ORIGINAL ARTICLE International Journal of Cardiovascular Sciences. 2018;31(6)585-593 Mailing Address: Fernando Luiz Affonso Fonseca Avenida Lauro Gomes, 2000. Postal Code: 09.060-050, Vila Príncipe de Gales, Santo André, SP - Brazil. E-mail: profferfonseca@gmail.com Effect of Mild Aerobic Exercise in Atrial Granules of Mice with Chronic Chagas Disease Roberto Ferraboli, 1 Elisabete De Marco Ornelas, 1 Fernando Luiz Affonso Fonseca, 2 Glaucia Luciano da Veiga, 2 Clever Gomes Cardoso, 3 Mara Rubia Marques, 3 Laura Beatriz Mesiano Maifrino 1,4 Universidade São Judas Tadeu, 1 SP - Brazil Faculdade de Medicina ABC, 2 SP - Brazil Universidade Federal de Goiás, 3 GO - Brazil Instituto Dante Pazzanese de Cardiologia, 4 SP - Brazil Manuscript received September 20, 2017, revised manuscript November 24, 2017, accepted December 20, 2017. Abstract Background: Chagas disease presents in different clinical forms, ranging from asymptomatic to acute, with destruction of heart cells and a possibility of death. In the chronic phase, the parasites can cause serious injuries to different tissues. Objectives: Our objectivewas to study the effects of physical exercise (swimming) in atrial granules and components of cardiomyocytes in mice with chronic Chagas disease. Methods: In total, 20 male mice were divided into four different groups: untrained control (UC), trained control (TC), untrained infected (UI), and trained infected (TI). In the UI and TI groups, 1,000 forms of Trypanosoma cruzi (Y strain) were inoculated intraperitoneally. After 40 days of infection and proof of chronic phase, the exercise protocol began. The UC and UI groups performed exercise for 10 min/day, and the TC and TI groups followed a training protocol five times a week for 30 minutes during 8 weeks. Ultrathin sections were subjected to morphometric and stereological analyses using electron photomicrographs (x15000) obtained by transmission electron microscopy. Results: The TI group showed the lowest percentage of small granules (58%), while the UI group presented 80% of these granules. The volume density of the Golgi complex and myofibrils in the TI group were reduced compared with those in the UI group, while the parameters of atrial granules and mitochondria increased. Conclusion: Our results suggest that mild physical exercise changes the morphological and morphometric parameters of granules and organelles in the cardiac atrium of mice infected with T. cruzi , and produces moderate beneficial effects on the cardiovascular system. (Int J Cardiovasc Sci. 2018;31(6)585-593) Keywords: Chagas Disease; Exercise; Atrial Natriuretic Factor; Mice. Introduction Cardiac manifestations of Chagas disease remain the leading cause of death in several countries in Latin America and have become a public health problem in nonendemic countries due tomigration. 1 Chronic Chagas heart disease is considered a major cause of nonischemic cardiomyopathy worldwide. 2 With an annual incidence of 28,000 cases in the region of the Americas, Chagas disease affects approximately 6 to 8 million people and causes, on average, about 12,000 deaths per year. 3 Chronic Chagas heart disease is characterized by cardiac dysfunction in varying degrees evolving to heart failure, bradycardia, biventricular cardiomyopathy or right ventricular dysfunction, severe arrhythmias, thromboembolism, syncope, and sudden death. It is a cardiomyopathywith a prognosis determined by systolic dysfunction and diastolic failure, especially among patients with heart failure. 2,4-6 Both atrial natriuretic peptide (ANP) and brain natriuretic peptide (BNP) are synthesized and stored in the cytoplasm of atrial and ventricular cardiomyocytes