Poor histological healing of a femoral fracture following 12 months of oestrogen deficiency in rats

• Published in: Osteoporosis international 2013-10, Vol.24 (10), p.2581-2589
• Main Authors: Oliver, R. A., Yu, Y., Yee, G., Low, A. K., Diwan, A. D., Walsh, W. R.
• Format: Article
• Language: English
• Subjects: Absorptiometry, Photon; Aging - pathology; Aging - physiology; Animals; Bone Density - physiology; Bones; Bony Callus - diagnostic imaging; Bony Callus - pathology; Bony Callus - physiopathology; Disease Models, Animal; Endocrinology; Estrogens; Estrogens - deficiency; Female; Femoral Fractures - diagnostic imaging; Femoral Fractures - pathology; Femoral Fractures - physiopathology; Fracture Healing - physiology; Fractures; Legs; Medicine; Medicine & Public Health; Original Article; Orthopedics; Osteoporosis; Osteoporosis - physiopathology; Osteoporotic Fractures - diagnostic imaging; Osteoporotic Fractures - pathology; Osteoporotic Fractures - physiopathology; Ovariectomy; Rats; Rats, Sprague-Dawley; Rheumatology; Rodents; Stress, Mechanical; Wound healing
• ISSN: 0937-941X; 1433-2965
• DOI: 10.1007/s00198-013-2345-2

Summary Fractures in post-menopausal osteoporosis cause significant morbidity; however, animal models for post-menopausal fracture healing lack the effect of ageing. Therefore, we developed a model using aged animals with chronic oestrogen deficiency, which demonstrates inferior fracture repair (decreased healing histologically, bone mineral density and content and strength). This novel model may help develop molecular strategies for osteoporotic fracture repair. Introduction The femur is susceptible to damage by both systemic conditions such as osteoporosis and locally by traumatic injury. The capacity for fracture repair decreases with age, while the risk of fracture increases. As studies of osteoporotic fracture healing in rats traditionally use a period of 3 months or less of oestrogen deficiency prior to fracturing, we aimed to establish a osteoporosis model in rats with chronic oestrogen deficiency by 12 months to better mimic human female osteoporosis. Methods Seventy female Sprague–Dawley rats (10 weeks old) were ovariectomised or sham operated and housed for 12 months. The right femur was fractured by way of an open osteotomy and fixed with an intramedullary Kirschner wire. Animals were sacrificed at 1, 3 and 6 weeks for radiography, dual-energy X-ray absorptiometry, tensile testing and histology. Results Bone mineral density and bone mineral content were lower by 60 and 63 %, respectively, ( p