Relationship between osteogenesis and angiogenesis in ovariectomized osteoporotic rats after exercise training

To reveal the role of exercise training in regulating osteogenesis and angiogenesis in rats after ovariectomy (OVX), then further examine the relationship between osteoporosis (OP) and local blood supply. Ninety-six rats were randomly assigned to OVX, OVX + exercise (OVX + Exe), sham operation (CON), and sham + exercise (CON + Exe) groups. Bone mineral density (BMD) was determined by dual-energy X-ray absorptiometer (DXA). Microarchitecture and angiogenesis of the femoral condyles were measured by micro-cumputed tomography (micro-CT). The femoral artery was separated for evaluating the vasodilation and endothelial nitric oxide synthase (eNOS) gene expression.BMD was markedly lower in the OVX than CON and CON + Exe groups. The trabecular bone integrity was better in the OVX + Exe than OVX group, but BMD showed no significant difference. The bone parameters indicated OP characteristics in rats after OVX, parts of them were relatively improved after exercise training. Acetylcholine-induced vessel vasodilation was enhanced by exercise training, but blocked by a NOS inhibitor. eNOS gene expression in femoral vessels showed a downward trend after OVX, and a upward trend in CON group, but seemed not to be affected by exercise training. Angiogenesis in the femur was lower in the OVX group than the CON group, but substantially better in the OVX + Exe than OVX group. Exercise training enhancing acetylcholine-induced femoral artery vasodilation and bone angiogenesis improve the blood supply of bone to facilitate osteogenesis in the OP site and therefore delay the progression of OP after menopause.