Aerobic Exercise-Assisted Cardiac Regeneration by Inhibiting Tryptase Release in Mast Cells after Myocardial Infarction.
BACKGROUND
Cardiovascular disease (CVD) contributes critically to the mortality, morbidity, and economic problem of illness globally. Exercise is a share of everyone's life. Some evidence-based studies have frequently shown a progressive correlation between physical activity and good health.


OBJECTIVE
The effects of daily exercise on cardiomyocyte size, collagen content (fibrosis), and releasing mast cells (MCs') tryptase of the model of myocardial infarction (MI) were assessed.


METHODS
40 rats were coincidentally spread into sham+inertia (control), sham+exercise, infarction+inertia, and infarction+exercise groups. An experimental model of acute MI was induced in infarction groups. One week after surgery, exercising groups were allowed to an aerobic exercise program for six weeks. At the endpoint of the study, all examinations were performed.


RESULTS
We found lesser fibrosis in sham+exercise and infarction+exercise groups compared to sham+inertia and infarction+inertia groups, respectively (p = 0.023, p = 0.001). Also, infarction groups were significantly lower than sham groups (p < 0.05) and the infarction+exercise group was significantly lower than the infarction+inertia group (p < 0.05). The effect of exercise on MCs while increased MC density and degranulation occur at the site of fibrosis, we demonstrated that exercise decreases both total MC density and degranulation in both sham and infarction groups (p < 0.05). Immunohistochemistry examinations were significantly higher expression of MCs' tryptase in infarction groups than sham groups (p < 0.05, p < 0.0001).


CONCLUSION
Exercise improves fibrosis and cardiac function in both healthy and MI rats by inhibiting released MCs' tryptase.