Osteoporotic rat models for evaluation of osseointegration of bone implants.

Osseointegration of dental and orthopedic bone implants is the important process that leads to mechanical fixation of implants and warrants implant functionality. In view of increasing numbers of osteoporotic patients, bone implant surface optimization strategies with instructive and drug-loading ability have been heavily explored. However, few animal models are available to study the effect of novel implant surface modifications in osteoporotic conditions. Since laboratory rats comply with a number of practical advantages, including the reliability of several methods for rapid induction of osteoporotic conditions, the present work aimed to define the use of the femoral condyle in osteoporotic female and male rats as a suitable implantation model to study osseointegration of bone implants. The method describes the procedures for induction (by hypogonadism) and assessment (by in vivo micro-computed tomography [CT]) of osteoporotic conditions in both female and male rats. The implantation site architecture (femoral condyle bone properties and dimensions) was comparatively evaluated for female and male rats, and the implant installation procedures are described. Finally, the possible analytical techniques to evaluate bone responses via mechanical tests, ex vivo micro-CT, and histological methods are provided.