A novel murine segmental femoral graft model.
To further understand the cellular and molecular mechanisms underlying cortical bone graft healing, we have developed a novel mouse femur model that permits quantitative and molecular analysis of structural bone graft healing. A 4 mm mid-diaphyseal femoral segment was removed and replaced by either immediate implantation of a fresh autograft, a frozen, genetically identical isograft or a frozen allograft from a different strain of mouse, which was secured with a 22-gauge metal intramedullary pin. Healing was evaluated by radiology, histomorphometry, and in situ hybridization. Autograft repair occurred by endochondral bone formation at the host-graft junction and by intramembranous bone formation along the length of the graft bed at 2 weeks, with maturation and remodeling apparent by 4 weeks. Bone repair in allografts and isografts completely relied on endochondral bone formation at the host-graft cortical junction, with absence of periosteal bone formation along the length of the graft, suggesting that live periosteal cells from the donor tissue are necessary for this response. This small animal model of structural bone grafting can be used to evaluate tissue-engineered allografts and novel bone graft substitutes using quantitative and molecularly defined outcome measures.
Department of Orthopaedics, The Center for Musculoskeletal Research, University of Rochester Medical Center, 601 Elmwood Avenue, NY 14642, USA.
Prarop
P
Tiyapatanaputi
Paul T
PT
Rubery
Jonathan
J
Carmouche
Edward M
EM
Schwarz
Regis J
RJ
O'keefe
Xinping
X
Zhang
D000818:Animals; D021461:Animals, Outbred Strains; D016025:Bone Transplantation; D005269:Femur / Q000166:cytology / Q000000981:diagnostic imaging / Q000637:transplantation*; D017102:Fracture Healing; D051379:Mice; D008810:Mice, Inbred C57BL; D023421:Models, Animal; D011859:Radiography; D014184:Transplantation, Homologous