Histomorphometric, physical, and mechanical effects of spaceflight and insulin-like growth factor-I on rat long bones
Histomorphometric, physical, and mechanical effects of spaceflight and insulin-like growth factor-I on rat long bones
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DOI：
10.1016/s8756-3282(98)00135-5
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发表时间：
1998-12-01
期刊：
影响因子：
4.1
通讯作者：
Simske, SJ
中科院分区：
文献类型：
--
作者：
Bateman, TA;Zimmerman, RJ;Simske, SJ
Previous experiments have shown that skeletal unloading resulting from exposure to microgravity induces osteopenia in rats. In maturing rats, this is primarily a function of reduced formation, rather than increased resorption, Insulin-like growth factor-I (IGF-I) stimulates bone formation by increasing collagen synthesis by osteoblasts. The ability of IGF-I to prevent osteopenia otherwise caused by spaceflight was investigated in 12 rats flown for 10 days aboard the Space Shuttle, STS-77, The effect IGF-I had on cortical bone metabolism was generally anabolic, For example, humerus periosteal bone formation increased a significant 37.6% for the spaceflight animals treated with IGF-I, whereas the ground controls increased 24.7%, This increase in humeral bone formation at the periosteum is a result of an increased. percent mineralizing perimeter (%Min.Pm), rather than mineral apposition rate (MAR), for both spaceflight and ground control rats. However, IGF-I did inhibit humerus endocortical bone formation in both the spaceflight and ground control rats (38.1% and 39.2%, respectively) by limiting MAR. This effect was verified in a separate ground-based study. Similar histomorphometric results for spaceflight and ground control rats suggest that IGF-I effects occur during normal weight bearing and during spaceflight, Microhardness measurements of the newly formed bone indicate that the quality of the bone formed during IGF-I treatment or spaceflight was not adversely altered. Spaceflight did not consistently change the structural (force-deflection) properties of the femur or humerus when tested in three-point bending. IGF-I significantly increased femoral maximum and fracture strength. (Bone 23:527-635; 1998) (C) 1998 by Elsevier Science Inc. All rights reserved.
