Aerobic Endurance Training Modulates Cardiac Renin-Angiotensin System Peptides and Matrix Metalloproteinase Activity During Chronic Stress.

To investigate the involvement of metalloproteinases (MMPs) in the context of endurance training and their interactions with renin-angiotensin signalling (RAS) in stress-induced pathophysiological responses. Trained rats were submitted to 8-weeks of endurance treadmill training with chronic mild stress (CMS), TS rats, and without CMS (T). Non-trained rats (NTS and NT groups) were submitted to identical procedures except for training. NTS and TS groups were submitted to a CMS protocol for 3 weeks. Elevated corticosterone levels indicate an initial triggering factor that mediates the downstream intracellular signalling networks related to the MMPs and RAS activation after CMS. Endurance training confers cardioprotection against the stress response by lowering the Ang 3-7 levels, whereas increased activity of MMPs was observed in TS rats. Chronic stress disrupts the cardiac function, MMPs, and RAS activation by increasing the cardiac activity of the MMP-2 activity and Ang 1-9 levels with concomitant reduction of cardiac and blood levels of Ang 1-7. Stress also reduced circulating levels of Ang 1-9 and Ang 1-5, Ang 1-7 metabolites, along with increased Ang III (2-8). Aerobic endurance training is a potential exercise-based strategy that counteracts the stress-related disturbances in the MMPs and RAS signalling pathways.