Oral administration of angiotensin-(1-7) decreases muscle damage and prevents the fibrosis in rats after eccentric exercise.

New finding What is the central question of this study? Eccentric contraction exercises cause damage to muscle fibers, induce inflammatory responses; the exacerbation of this process can induce deposition of fibrous connective tissue, leading to decreased muscle function. The aim of this study is to examine the role of Angiotensin-(1-7) in this context. What is the main finding and its importance? Our results show that oral treatment with Angiotensin-(1-7) decreases muscle damage induced by eccentric exercise, reducing inflammation and fibrosis in the gastrocnemius and soleus muscle. This study shows potential effect of Ang-(1-7) for the prevention of muscle injuries induced by physical exercise. Abstract Eccentric contraction exercises cause damage to the muscle fibers and induce inflammatory reaction. The protective effect of Angiotensin-(1-7) [Ang-(1-7)] in skeletal muscle has led us to examine the role that this peptide plays in modifying processes associated with inflammation and fibrogenesis induced by eccentric exercise. In this study, we sought to investigate the effects of the oral administration of Ang-(1-7) included in hydroxypropyl β-cyclodextrin (HPβ-CD) in preventing and treating muscle damage following downhill running. Male Wistar rats were divided into three groups: control (untreated and not exercised) (n = 10), treated/exercised HPβ-CD Ang-(1-7) (n = 40), and treated/exercised HPβ-CD (n = 40). Exercised groups were subjected to a single eccentric contraction exercise session on a treadmill inclined to -13° and a constant speed of 20 m.min-1, for 60 min. Oral administration with HPβ-CD Ang-(1-7) and HPβ-CD was performed three hours before the exercise protocol and daily as a single dose, until day of euthanasia. Samples were collected at 04/12/24/48 and 72 hours after the exercise session. The animals treated with the Ang-(1-7) showed lower levels of CK, lower levels of TNF-α in soleus muscle and increased levels of IL-10 cytokines. The inflammatory cells and deposition of fibrous connective tissue were lower in the group treated with Ang-(1-7) in soleus and gastrocnemius muscles. The results of this study show that treatment with an oral formulation of Ang-(1-7) plays a fundamental role in the process of muscle injury repair induced by eccentric exercise. This article is protected by copyright. All rights reserved.