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Exercise‐induced increases in trabecular bone volume are associated with increased nitric oxide‐mediated vasodilation in osseous vasculature of young and old rats
Author(s) -
Dominguez James Michael,
Prisby Rhonda D.,
Allen Matthew R.,
Delp Michael D.
Publication year - 2009
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.23.1_supplement.955.21
Subject(s) - vasodilation , nitric oxide , endocrinology , medicine , endothelium , nitric oxide synthase , osteoporosis , aerobic exercise
Old age‐associated osteoporosis is related to diminished bone blood flow and impaired nitric oxide (NO)‐mediated vasodilation. The purpose of this study was to determine whether exercise training enhances endothelium‐dependent vasodilation and correspondingly improves bone volume in aged animals. Young adult (4‐6mo) and old (24‐26mo) male Fischer‐344 rats remained sedentary or were exercise trained (15m/min, 15 o incline, 5days/wk, 10‐12wk). Endothelium‐dependent vasodilation of the femoral principle nutrient artery was assessed in vitro using acetylcholine (ACh) and inhibitors of NO synthase (NOS) and cyclooxygenase (COX) were used to determine the signaling pathways involved. Endothelium‐dependent vasodilation was greater after exercise training (young: 87±3%; old: 73±5% relaxation) compared to sedentary (young: 75±6%; old: 59±5% relaxation). In old rats, the NOS‐mediated contribution to endothelium‐dependent vasodilation was enhanced by exercise training. Distal femur trabecular bone volume (BV/TV) was significantly reduced with old age in sedentary animals (young: 27±2%; old: 23±1%). Exercise training increased BV/TV in both groups (young: 34±2%; old: 26±1%) compared to sedentary. These data are the first to demonstrate that exercise training impacts the osseous vasculature. Moreover, a training‐induced elevation in the NOS signaling pathway is associated with greater trabecular bone volume.