EFFECTS OF AGING AND EXERCISE ON BONE MASS

随着年龄的增长，骨量丢失，骨折发生率随之增加 是一个重大的医疗和社会问题。 有 目前没有接受的治疗II型，或年龄相关的（老年） 骨质疏松 体育锻炼被认为是一种可能的治疗方法 对于或预防措施，对年龄相关的骨质流失，但大多数过去 由于缺乏足够的控制，研究受到了影响。 还有， 关于运动与运动之间相互作用的几个重要问题 治疗和其他因素尚未得到充分研究。 在这 一项研究表明，比格犬随着年龄的增长会失去骨骼。 以类似于人类的方式，将被用作研究 增加体育锻炼对受试者骨量的影响 环境 实验室里有24只雌性比格犬，年龄从 8到13年，相当于人类的60到80年， 将每天进行20分钟的分级跑步机跑步， 个月 治疗效果将在体内使用双抗体夹心法进行评价。 能量光子吸收测定法或定量数字X射线摄影，以及 计算机断层扫描。 使用这些技术，骨矿物质含量的 股骨远端和中段、腰椎和上下颌，以及 将在12个月前确定股骨中段的皮质几何结构 治疗开始和结束时以及治疗后8个月 治疗 个体治疗前基线变化率 参数将与治疗期间和治疗后的变化率进行比较。 治疗周期。 动物在所有阶段的活动水平也将 被监视。 这项研究的长期目标是确定 适度剧烈的体育锻炼可以用来治疗或预防衰老， 相关的骨质流失 几个具体因素对 将研究运动治疗的疗效：初始受试者年龄 和机械负荷的相对活动水平或基线增加， 和运动治疗期后对去适应的反应。

Loss of bone mass with aging and consequent increase in fracture incidence among the elderly is a major medical and societal problem. There is currently no accepted treatment for type II, or age-related (senile) osteoporosis. Physical exercise has been suggested as a possible treatment for or preventive measure against age-related bone loss, but most past studies have been compromised by lack of sufficient controls. Also, several important issues regarding the interaction between exercise treatment and other factors have been inadequately studied. In this investigation, the Beagle dog, which has been shown to lose bone with aging in a manner similar to that of humans, will be used as a model to study the effects of increased physical exercise on bone mass in a controlled environment. 24 female Beagles in a laboratory colony ranging in age from 8 to 13 years, equivalent to humans in the sixth through eighth decades, will be subjected to 20 minutes per day of graded treadmill running for 8 months. The effects of the treatment will be evaluated in vivo using dual energy photon absorptiometry or quantitative digital radiography, and computed tomography. Using these techniques, bone mineral content of the distal and midshaft femur, lumbar vertebrae, and mandible-maxillae, and cortical geometry of the midshaft femur will be determined 12 months prior to treatment, at the beginning and end of treatment, and 8 months after treatment. Individual pre-treatment baseline rates of change in these parameters will be compared with rates of change during treatment and post- treatment periods. Activity levels of the animals in all periods will also be monitored. The long-term goal of the study is to determine if moderately strenuous physical exercise can be used to treat or prevent age- related bone loss. The influence of several specific factors on the efficacy of exercise treatment will be investigated: initial subject age and relative activity level or baseline increases in mechanical loading, and response to deconditioning following an exercise treatment period.