The Level Of Improvement In The Function Of Bone Marrow Derived Endothelial Progenitor Cells Is Dependent On The Volume Of Aerobic Exercise Training

Introduction: Skeletal muscle angiogenesis induced by aerobic exercise training (ET) is crucial in the improvement of the aerobic capacity. The endothelial progenitor cells (EPC) derived from bone marrow have been described for promoting both the vascular repair and angiogenesis. Although the role of the ET on the parameters of the EPC has been investigated, the effect of different volumes of ET on the EPC function in bone marrow, skeletal muscle metabolic alterations and capillarization are unknown. Objective: We hypothesized that ET improves the EPC function in bone marrow, accompanied by increase of skeletal muscle oxidative capacity and angiogenesis dependents of the increase of volume of ET. Methods: Twenty-one Wistar rats were divided into 3 groups: sedentary control (SC), trained protocol 1 (T1) and trained protocol 2 (T2). T1: swimming training consisted of 60 min, 1x/day/10 weeks, with 5% body weight load. T2 the same as T1 until 8(th) week, in the 9(th) week the rats trained 2x/day and in the 10(th) week 3x/day. Results: ET promoted resting bradycardia, increase of exercise tolerance, peak oxygen uptake and citrate synthase enzyme activity in the T1 group, being these adaptive responses exacerbate in the P2 group, indicating that the aerobic condition was improved in this group. ET improved the EPC function of the bone marrow in T1, and the response was exacerbated in T2 group. In parallel, increase in the number of capillaries dependent of ET volume was also observed. Conclusion: These findings suggest that the bone marrow as the main reservoir of EPC is influenced by different ET volume, possibly being responsible for the improvement of aerobic performance observed by higher endogenous EPC mobilization, active participants in the process of angiogenesis induced by ET.