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Mineral density and bone strength are dissociated in long bones of rat osteopetrotic mutations.
J Bone Miner Res. 2000 Oct; 15(10):1905-11.JB

Abstract

Bone mineral density (BMD) and mechanical strength generally show strong positive correlations. However, osteopetrosis is a metabolic bone disease with increased skeletal density radiographically and increased risk of fracture. We have evaluated mechanical strength and mineral density in three osteopetrotic mutations in the rat (incisors-absent [ia/ia], osteopetrosis [op/op], and toothless [tl/tl]) to test the hypothesis that reduced bone resorption in one or more of these mutations results in weaker bones in the presence of greater mineral density and skeletal mass. Peripheral quantitative computed tomography (pQCT) was used to analyze BMD and cross-sectional geometry in the tibial diaphysis and metaphysis as well as the femoral diaphysis and femoral neck. The bending breaking force of tibial and femoral midshafts was obtained using the three-point bending test and femoral neck strength was tested by axial loading. Osteopetrotic mutants were significantly smaller than their normal littermates (NLMs) in each stock. The pQCT analysis showed that BMD and bone mineral content (BMC) were higher than or equal to NLMs in all skeletal sites measured in the osteopetrotic mutants. However, the mechanical breaking force was equal to or lower than their NLMs in all sites. The cross-sectional structure of long bone shafts was markedly different in osteopetrotic mutants, having a thin cortex and a medullary area filled with primary trabecular bone. These results indicate that osteopetrotic mutations in the rat increase bone density and decrease bone strength. The tibial diaphysis was significantly weaker in tl/tl and ia/ia mutants and the tibial metaphysis showed the greatest increase in BMD in all mutants. These data are another illustration that an increased BMD does not necessarily lead to stronger bones.

Authors+Show Affiliations

Department of Anatomy and Cell Biology, University of Oulu, Finland.No affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info available

Pub Type(s)

Journal Article

Language

eng

PubMed ID

11028442

Citation

Tuukkanen, J, et al. "Mineral Density and Bone Strength Are Dissociated in Long Bones of Rat Osteopetrotic Mutations." Journal of Bone and Mineral Research : the Official Journal of the American Society for Bone and Mineral Research, vol. 15, no. 10, 2000, pp. 1905-11.
Tuukkanen J, Koivukangas A, Jämsä T, et al. Mineral density and bone strength are dissociated in long bones of rat osteopetrotic mutations. J Bone Miner Res. 2000;15(10):1905-11.
Tuukkanen, J., Koivukangas, A., Jämsä, T., Sundquist, K., Mackay, C. A., & Marks, S. C. (2000). Mineral density and bone strength are dissociated in long bones of rat osteopetrotic mutations. Journal of Bone and Mineral Research : the Official Journal of the American Society for Bone and Mineral Research, 15(10), 1905-11.
Tuukkanen J, et al. Mineral Density and Bone Strength Are Dissociated in Long Bones of Rat Osteopetrotic Mutations. J Bone Miner Res. 2000;15(10):1905-11. PubMed PMID: 11028442.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Mineral density and bone strength are dissociated in long bones of rat osteopetrotic mutations. AU - Tuukkanen,J, AU - Koivukangas,A, AU - Jämsä,T, AU - Sundquist,K, AU - Mackay,C A, AU - Marks,S C,Jr PY - 2000/10/12/pubmed PY - 2001/3/3/medline PY - 2000/10/12/entrez SP - 1905 EP - 11 JF - Journal of bone and mineral research : the official journal of the American Society for Bone and Mineral Research JO - J Bone Miner Res VL - 15 IS - 10 N2 - Bone mineral density (BMD) and mechanical strength generally show strong positive correlations. However, osteopetrosis is a metabolic bone disease with increased skeletal density radiographically and increased risk of fracture. We have evaluated mechanical strength and mineral density in three osteopetrotic mutations in the rat (incisors-absent [ia/ia], osteopetrosis [op/op], and toothless [tl/tl]) to test the hypothesis that reduced bone resorption in one or more of these mutations results in weaker bones in the presence of greater mineral density and skeletal mass. Peripheral quantitative computed tomography (pQCT) was used to analyze BMD and cross-sectional geometry in the tibial diaphysis and metaphysis as well as the femoral diaphysis and femoral neck. The bending breaking force of tibial and femoral midshafts was obtained using the three-point bending test and femoral neck strength was tested by axial loading. Osteopetrotic mutants were significantly smaller than their normal littermates (NLMs) in each stock. The pQCT analysis showed that BMD and bone mineral content (BMC) were higher than or equal to NLMs in all skeletal sites measured in the osteopetrotic mutants. However, the mechanical breaking force was equal to or lower than their NLMs in all sites. The cross-sectional structure of long bone shafts was markedly different in osteopetrotic mutants, having a thin cortex and a medullary area filled with primary trabecular bone. These results indicate that osteopetrotic mutations in the rat increase bone density and decrease bone strength. The tibial diaphysis was significantly weaker in tl/tl and ia/ia mutants and the tibial metaphysis showed the greatest increase in BMD in all mutants. These data are another illustration that an increased BMD does not necessarily lead to stronger bones. SN - 0884-0431 UR - https://www.unboundmedicine.com/medline/citation/11028442/Mineral_density_and_bone_strength_are_dissociated_in_long_bones_of_rat_osteopetrotic_mutations_ L2 - https://doi.org/10.1359/jbmr.2000.15.10.1905 DB - PRIME DP - Unbound Medicine ER -