McCarthy R N, Jeffcott L B
Department of Veterinary Science, University of Melbourne, Veterinary Clinic and Hospital, Victoria, Australia.
Res Vet Sci. 1992 Jan;52(1):28-37. doi: 10.1016/0034-5288(92)90054-6.
The effects of exercise and relative inactivity on cortical bone were compared in young horses. Two groups were used; one was given a 14-week programme of exercise (n = 6) and the other kept as unexercised controls (n = 6). The first nine weeks of exercise involved trotting and cantering (2 to 4 km d-1 at speeds up to 12 m s-1) on a treadmill set at an incline of 3 degrees. Over the next five weeks the horses were trained at near maximal speeds (that is, up to 14.5 m s-1) with no incline of the treadmill. At the end of the programme marked differences in cortical porosity and distribution of subperiosteal osteogenesis at the mid-shaft of the third metacarpal bone were found between the groups. Histomorphometrical examination of the dorsal cortex showed minimal bone remodelling in the exercised horses, but extensive modelling as evidenced by the large amount of subperiosteal bone formation. In contrast, the unexercised horses had significantly more bone remodelling and less formation of subperiosteal bone. The histomorphometric and microradiographic findings provided an explanation for changes in the non-invasive bone measurements that occurred during training. Bone mineral content of the mid-metacarpus was found to increase more in the exercised than the unexercised horses despite a lower overall growth in bodyweight. In those horses that completed the full training programme, ultrasound speed increased significantly by the end of the training programme. It remained unchanged in the horse that did not complete the full exercise programme and decreased slightly in the unexercised horses. The difference in ultrasound speed between the groups was considered to reflect differences in intracortical bone porosity, endosteal bone formation and alterations in skin thickness. The stiffness of cortical bone increased significantly in the exercised horses but remained unaltered in the unexercised horses.
对幼年马匹运动和相对不运动对皮质骨的影响进行了比较。使用了两组；一组进行为期14周的运动计划（n = 6），另一组作为不运动的对照组（n = 6）。运动的前九周包括在倾斜3度的跑步机上小跑和慢跑（每天2至4公里，速度高达12米/秒）。在接下来的五周里，马匹以接近最大速度（即高达14.5米/秒）进行训练，跑步机不倾斜。在该计划结束时，发现两组之间在第三掌骨中轴的皮质孔隙率和骨膜下骨生成分布存在明显差异。对背侧皮质的组织形态计量学检查显示，运动马匹的骨重塑最少，但大量骨膜下骨形成证明有广泛的骨建模。相比之下，不运动的马匹有明显更多的骨重塑和更少的骨膜下骨形成。组织形态计量学和显微放射学结果为训练期间发生的无创骨测量变化提供了解释。尽管体重总体增长较低，但运动马匹掌骨中部的骨矿物质含量增加幅度大于不运动的马匹。在完成完整训练计划的马匹中，到训练计划结束时超声速度显著增加。未完成完整运动计划的马匹中超声速度保持不变，不运动的马匹中超声速度略有下降。两组之间超声速度的差异被认为反映了皮质内骨孔隙率、骨内膜骨形成和皮肤厚度变化的差异。运动马匹的皮质骨刚度显著增加，而不运动的马匹则保持不变。
