The Skeletal Structure of Insulin-Like Growth Factor I-Deficient Mice
| Autor: | Colin Leary, Bernard P. Halloran, Lyn Powell-Braxton, Clifford J. Rosen, Sharmila Majumdar, Andres Laib, Wesley G. Beamer, Daniel D. Bikle, Eric A. Nauman |
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| Rok vydání: | 2001 |
| Předmět: |
Male
medicine.medical_specialty Bone density Ratón Endocrinology Diabetes and Metabolism medicine.medical_treatment Biology Bone and Bones Mice Insulin-like growth factor Sex Factors Bone Density Osteogenesis Internal medicine medicine Animals Orthopedics and Sports Medicine Tibia Insulin-Like Growth Factor I Mice Knockout Ossification Growth factor Skeleton (computer programming) Endocrinology Growth Hormone Knockout mouse Female medicine.symptom |
| Zdroj: | Journal of Bone and Mineral Research. 16:2320-2329 |
| ISSN: | 0884-0431 |
| DOI: | 10.1359/jbmr.2001.16.12.2320 |
| Popis: | The importance of insulin-like growth factor I (IGF-I) for growth is well established. However, the lack of IGF-I on the skeleton has not been examined thoroughly. Therefore, we analyzed the structural properties of bone from mice rendered IGF-I deficient by homologous recombination (knockout [k/o]) using histomorphometry, peripheral quantitative computerized tomography (pQCT), and microcomputerized tomography (muCT). The k/o mice were 24% the size of their wild-type littermates at the time of study (4 months). The k/o tibias were 28% and L1 vertebrae were 26% the size of wild-type bones. Bone formation rates (BFR) of k/o tibias were 27% that of the wild-type littermates. The k/o bones responded normally to growth hormone (GH; 1.7-fold increase) and supranormally to IGF-I (5.2-fold increase) with respect to BFR. Cortical thickness of the proximal tibia was reduced 17% in the k/o mouse. However, trabecular bone volume (bone volume/total volume [BV/TV]) was increased 23% (male mice) and 88% (female mice) in the k/o mice compared with wild-type controls as a result of increased connectivity, increased number, and decreased spacing of the trabeculae. These changes were either less or not found in L1. Thus, lack of IGF-I leads to the development of a bone structure, which, although smaller, appears more compact. |
| Databáze: | OpenAIRE |
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