title: Mechanical properties in long bones of rat osteopetrotic mutations.
abstract: Osteopetrosis is a metabolic bone disease with increased skeletal density radiographically and increased risk of fracture. Experimental studies with rat osteopetrotic mutations have shown increased bone density and decreased bone strength. However, it is not known if this reduction in bone strength is only due to changes in structure and geometry or if the tissue properties of bone material itself are changed as well. We have evaluated bone tissue properties with nanoindentation 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 these mutations results in reduced tissue properties of bone material. No significant differences in elastic modulus or hardness were found between osteopetrotic mutants and their normal littermates (NLMs) in any of the three stocks. This indicates that the tissue properties of bone material are not changed significantly in osteopetrosis, even if the mechanical strength is decreased at the macroscopic level.
authors.affiliation: Department of Medical Technology, University of Oulu, P.O. Box 5000, 90014 Oulu, Finland. timo.jamsa@oulu.fi
authors.forename: Timo
authors.initials: T
authors.lastname: Jämsä
authors.forename: Jae-Young
authors.initials: JY
authors.lastname: Rho
authors.forename: Zaifeng
authors.initials: Z
authors.lastname: Fan
authors.forename: Carole A
authors.initials: CA
authors.lastname: MacKay
authors.forename: Sandy C
authors.initials: SC
authors.lastname: Marks
authors.forename: Juha
authors.initials: J
authors.lastname: Tuukkanen
mesh_terms: D000818:Animals; D001696:Biomechanical Phenomena; D005269:Femur / Q000503:physiopathology*; D009154:Mutation; D010022:Osteopetrosis / Q000235:genetics* / Q000503:physiopathology*; D051381:Rats; D011922:Rats, Mutant Strains; D012016:Reference Values; D013977:Tibia / Q000503:physiopathology*