Osteoporotic Rat Models for Evaluation of Osseointegration of Bone Implants

Abstract

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.

The performance of CPC/PLGA and Bio‐Oss® for bone regeneration in healthy and osteoporotic rats

“…The removal of the ovaries or testis induces a decline in estrogen or androgen levels, respectively, which leads to a rapid loss of cancellous bone mass and strength . The most conventional osteoporotic animal model is the ovariectomized (OVX) rat, which mimics the bone changes in humans following menopause or oöphorectomy . Bone loss occurs first in trabecular bone, after which cortical bone is affected .…”

Hydroxyapatite‐doped alginate beads as scaffolds for the osteoblastic differentiation of mesenchymal stem cells

“…The resulting scaffold will contain bone matrix components from the initial scaffold as well as cell‐laid matrix, which mimics the nanoscale architecture and bioactive moieties of natural bone. In a proof of concept evaluation, these developed scaffolds are implanted in an orthotopic model to assess the capacity for osseointegration and new bone formation …”

“…After sufficient culture time, osteoblastic differentiation, and matrix production, the scaffolds will be implanted into rat femoral condyle defects. This orthotopic site implant allows for the evaluation of integration with the native bone tissue and the ability of the construct to promote healing of the defect site …”

Osteogenesis around CaP‐coated titanium implants visualized using 3D histology and micro‐computed tomography

“…Consequently, it is important to study this tissue reorganization phenomena in 3D. This becomes even more important when the dynamic equilibrium of balance is disturbed, as is the case in osteoporosis, a compromised bone condition affects the finally achieved implant fixation . Several high resolution 3D analysis techniques are available to study bone.…”