title: Osteoporosis influences the early period of fracture healing in a rat osteoporotic model.
abstract: Osteoporotic fractures commonly occur in the elderly. Although current therapies are aimed at the prevention and treatment of osteoporotic fractures, studies examing the fracture healing process in osteoporotic bone are limited. We produced an osteoporotic rat model by ovariectomy (ovx) and maintained a low calcium diet (LCD) in order to evaluate the influence of osteoporosis on fracture healing. Callus formation and strength was monitored over a 3 week period by histological and biomechanical assessment. Data collected simultaneously on a group of rats undergoing sham surgery (sx) were used for comparison. A 40% reduction in fracture callus cross-sectional area and a 23% reduction in bone mineral density in the healing femur of the ovx rats was observed on day 21 following fracture as compared with the sx group (p < 0.01). Biomechanical data from the healing femur of the ovx rats revealed a fivefold decrease in the energy required to break the fracture callus, a threefold decrease in peak failure load, a twofold decrease in stiffness and a threefold decrease in stress as compared with the sx group (p < 0.01, respectively). Histomorphological analysis revealed a delay in fracture callus healing with poor development of mature bone in the ovx rats. This study provides physical evidence of altered fracture healing in osteoporotic bone, which may have important implications in evaluating the effects of new treatments for osteoporosis on fracture healing.
authors.affiliation: Department of Endocrinology, St. George Hospital, University of New South Wales, NSW, Kogarah, Australia.
authors.forename: H
authors.initials: H
authors.lastname: Namkung-Matthai
authors.forename: R
authors.initials: R
authors.lastname: Appleyard
authors.forename: J
authors.initials: J
authors.lastname: Jansen
authors.forename: J
authors.initials: J
authors.lastname: Hao Lin
authors.forename: S
authors.initials: S
authors.lastname: Maastricht
authors.forename: M
authors.initials: M
authors.lastname: Swain
authors.forename: R S
authors.initials: RS
authors.lastname: Mason
authors.forename: G A
authors.initials: GA
authors.lastname: Murrell
authors.forename: A D
authors.initials: AD
authors.lastname: Diwan
authors.forename: T
authors.initials: T
authors.lastname: Diamond
mesh_terms: D000818:Animals; D015519:Bone Density; D002146:Bony Callus / Q000473:pathology / Q000503:physiopathology*; D002136:Calcium, Dietary / Q000494:pharmacology; D004195:Disease Models, Animal; D004967:Estrogens / Q000172:deficiency; D005260:Female; D005264:Femoral Fractures / Q000473:pathology / Q000503:physiopathology*; D005265:Femoral Neck Fractures / Q000473:pathology / Q000503:physiopathology; D010024:Osteoporosis / Q000473:pathology / Q000503:physiopathology*; D010052:Ovariectomy; D051381:Rats; D017207:Rats, Sprague-Dawley
chemical_list: D002136:Calcium, Dietary; D004967:Estrogens