title: The mechanical strength of bone in different rat models of experimental osteoporosis.
abstract: In order to discover good parameters for experimental osteoporosis, we measured the failure load of the femoral neck and the bending strength of the tibia in orchidectomized (ORC) (20 rats for 4 weeks), ovariectomized (OVX) (28 rats for 6 weeks), and immobilized (IMM) (33 rats for 3 weeks) rats. Each of these operations led to a significant decrease in trabecular bone volume when compared with corresponding controls (p < 0.001). The ash weight of femurs was significantly decreased in ORC (p < 0.05) and IMM (p < 0.001) rats, but not in OVX rats. Growth of the femur was somewhat slower in ORC (p < 0.05) and IMM rats (p < 0.05), but not in OVX animals. All three osteoporosis models showed significant decreases in the maximal load of the femoral neck (ORC: 23.9%, p < 0.001; OVX: 15.8%, p < 0.001; IMM: 27.7%, p < 0.001), as well as in energy absorption (ORC: 43.9%, p < 0.001; OVX: 28.3%, p < 0.001; IMM: 45.3%, p < 0.001). In tibia orchidectomy reduced maximal strength and energy absorption significantly (10%, p < 0.01; 27.8%, p < 0.01), but ovariectomy decreased only maximal load (8.7%, p < 0.01) and immobilization only energy absorption (18.0%, p < 0.01). Our results suggest that the mechanical strength of the femoral neck is a sensitive indicator of bone loss in all three osteoporosis models.
authors.affiliation: Department of Anatomy, University of Oulu, Finland.
authors.forename: Z
authors.initials: Z
authors.lastname: Peng
authors.forename: J
authors.initials: J
authors.lastname: Tuukkanen
authors.forename: H
authors.initials: H
authors.lastname: Zhang
authors.forename: T
authors.initials: T
authors.lastname: Jämsä
authors.forename: H K
authors.initials: HK
authors.lastname: Väänänen
mesh_terms: D000818:Animals; D001696:Biomechanical Phenomena; D003627:Data Interpretation, Statistical; D004195:Disease Models, Animal; D005260:Female; D005272:Femur Neck / Q000502:physiology*; D006801:Humans; D007103:Immobilization; D008297:Male; D009919:Orchiectomy; D010024:Osteoporosis / Q000473:pathology / Q000503:physiopathology*; D015663:Osteoporosis, Postmenopausal / Q000473:pathology / Q000503:physiopathology*; D010052:Ovariectomy; D051381:Rats; D017207:Rats, Sprague-Dawley; D013718:Tensile Strength; D013977:Tibia / Q000502:physiology*