Degradation and Recovery of Bone: OVX and Treatment

骨的退化和恢复：OVX 和治疗

• 批准号: 7050616
• 负责人: CLIFFORD MICHAEL LES
• 金额: $ 15.7万
• 依托单位: HENRY FORD HEALTH SYSTEM
• 依托单位国家: 美国
• 财政年份: 2005
• 资助国家: 美国
• 起止时间: 2005-04-07 至 2010-02-28
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7050616
• 关键词: bone fracture; bone metabolism; disease /disorder proneness /risk; elasticity; estrogens; hormone therapy; mechanical stress; nonhuman therapy evaluation; osteogenesis; osteoporosis; ovariectomy; sheep; skeletal stress; tensile strength; viscosity

DESCRIPTION (provided by applicant): Age-related bone fracture is only partially explained by the reduction in bone mass that universally occurs with aging. The failure to predict fracture comes in part from a) the loss of geometrical information when projection x-ray methods are used to measure bone mass, b) ignorance of sufficiently detailed information about the failure properties of bone, and also c) ignorance of detailed in vivo loads on bones (Fracture risk is related to the ratio of load to strength, rather than to bone strength alone). A fourth barrier to accurately predicting fracture risk is that changes in bone tissue mechanical properties caused by age or disease related changes in the collagen, non-collagenous proteins or water content of bone are not detectable to xray methods. As a result of the invisibility of soft tissue changes to x-ray detection, there are age and menopause related changes in tissue material properties (in bone quality) that are invisible, not understood and that unpredictably increase bone fracture risk. Our data support the novel working hypotheses: 1) The viscoelastic properties of bone affect the fracture toughness and apparent strength of bone tissue, 2) The viscoelastic properties of ovine bone degrade after ovariectomy, causing a decrease in the strength and fracture toughness of bone tissue for rates of loading associated with falls. The main goal of the proposed work is to determine the onset time of viscoelastic property degradation and whether cortical bone can recover normal viscoelastic and strength properties with estrogen replacement.

描述（由申请人提供）：与年龄相关的骨折仅由衰老普遍发生的骨骼质量减少而部分解释。无法预测骨折的部分原因是A）当使用投影X射线方法来测量骨骼质量时，几何信息的丧失，b）无知有关骨骼故障特性的充分详细信息，以及C）bones上详细的体内载荷的无知（骨折风险与负载与强度与强度相关，而不是与骨强度相关，而不是骨强度，而不是骨强度）。准确预测断裂风险的第四个障碍是，X射线方法无法检测到胶原蛋白，非胶原蛋白或骨骼的骨骼与疾病相关的变化引起的骨组织机械性能的变化。由于软组织对X射线检测的变化变化，组织材料特性（骨质质量）的年龄和更年期的变化是看不见的，尚不理解，并且无法预测地增加骨折风险。 我们的数据支持新的工作假设：1）骨骼的粘弹性影响骨骼组织的断裂韧性和明显的强度，2）卵巢切除术后卵巢骨降解的粘弹性特性，导致骨骼组织的强度和分裂耐力降低与跌落相关的骨骼组织的强度和分裂。 拟议工作的主要目的是确定粘弹性降解的发作时间，以及皮质骨是否可以通过替代雌激素恢复正常的粘弹性和强度性能。