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PROTOCOL
Evaluation of bone regeneration using the rat critical size calvarial defect
Patrick P Spicer1,5, James D Kretlow1,2,5, Simon Young1,3, John A Jansen4, F Kurtis Kasper1 & Antonios G Mikos1
1Department of Bioengineering, Rice University, Houston, Texas, USA. 2Department of General Surgery, Division of Plastic Surgery, Baylor College of Medicine, Houston, Texas, USA. 3Department of Oral and Maxillofacial Surgery, University of Texas Health Science Center at Houston, Houston, Texas, USA. 4Department of Biomaterials, Radboud University Nijmegen Medical Centre, Nijmegen, The Netherlands. 5These authors contributed equally to this work. Correspondence should be addressed to A.G.M. ([email protected])
Published online 27 September 2012; doi:10.1038/nprot.2012.113
Animal models that are reliably reproducible, appropriate analogs to the clinical condition they are used to investigate, andthat offer minimal morbidity and periprocedural mortality to the subject, are the keystone to the preclinical development of translational technologies. For bone tissue engineering, a number of small animal models exist. Here we describe the protocol for one such model, the rat calvarial defect. This versatile model allows for evaluation of biomaterials and bone tissue engineering approaches within a reproducible, non-load-bearing orthotopic site. Crucial steps for ensuring appropriate experimental control and troubleshooting tips learned through extensive experience with this model are provided. The surgical procedure itself takes ~30 min to complete, with ~2 h of perioperative care, and tissue collection is generally performed 412 weeks postoperatively. Several analytical techniques are presented, which evaluate the cellular and extracellular matrix components, functionality and mineralization, including histological, mechanical and radiographic methods.
2012 Nature America, Inc. All rights reserved.
INTRODUCTION
Bone regeneration represents a substantial component of clinical practice aimed at filling defects arising from trauma, congenital defects and tumor excision. Although numerous current clinical strategies can be applied to address these defects, the nonunion defect (Box 1), defined as incomplete closure of the defect, remains a clinical challenge1,2. Many different strategies are currently being investigated to address the challenge presented by nonunion; however, adequate testing of such strategies is necessary before they can be translated into human use. Historically and at present, animal testing of pharmaceuticals, medical devices and medical strategies has had a key role in the translation of many therapeutics into clinics. Despite ethical concerns and efforts to develop alternatives to animal experimentation, standardized animal models are crucial...