Temporal evolution of mechanical properties of skeletal tissue regeneration in rabbits: an experimental study

Abstract

Various mathematical models represent the effects of local mechanical environment on the regulation of skeletal regeneration. Their relevance relies on an accurate description of the evolving mechanical properties of the regenerating tissue. The object of this study was to develop an experimental model which made it possible to characterize the temporal evolution of the structural and mechanical properties during unloaded enchondral osteogenesis in the New Zealand rabbit, a standard animal model for studies of osteogenesis and chondrogenesis. A 25 mm segment of tibial diaphysis was removed sub-periosteally from rabbits. The defect was repaired by the preserved periosteum. An external fixator was applied to prevent mechanical loading during osteogenesis. The regenerated skeletal tissues were studied by CT scan, histology and mechanical tests. The traction tests between 7 and 21 days post-surgery were done on formaldehyde-fixated tissue allowing to obtain force/displacement curves. The viscoelastic properties of the regenerating skeletal tissues were visualized throughout the repair process.

Temporal evolution of skeletal regenerated tissue: what can mechanical investigation add to biological?

“…The overall geometry of the regenerated segment is thus still evolving [16]. This is in good agreement with the histology analysis which showed a massive cellular proliferation.…”

“…A first in-vivo study based on periosteal properties demonstrated that it is possible to regenerate a whole bone volume after a large segmental resection in the New-Zealand rabbit [16]. Moukoko [16] produced regenerated osteocular material under almost nought mechanical load, analyzing the time sequences of the regeneration process.…”

“…Moukoko [16] produced regenerated osteocular material under almost nought mechanical load, analyzing the time sequences of the regeneration process. Preserved periosteal sleeve from the resected bone, brought mesenchymal precursor cells into the surgical bed, which led to the initiation of osteogenesis within the volume determined by bone resection [16,17].…”

“…To the authors' knowledge, there was no experimental validation during the transitional period of transformation. Moukoko et al [16] gave first results for 7,-14-and-21-days-old tissue obtained with mechanical traction tests and histological tests. After 14 days of maturation, results showed a mineralizing tissue whose mechanical characteristics were stiffer than those of cartilage and closer to those of bone.…”

Connecting biology and mechanics in fracture healing: an integrated mathematical modeling framework for the study of nonunions

“…Isaksson et al (2009) have shown that although the sequential order of events in the predicted healing process is not significantly influenced by the chosen material properties, the amount of bone formation and mechanical stability at different stages of the healing process and the time to healing were significantly affected by the permeability of granulation tissue, the Young's modulus of cartilage and permeability of immature bone, and therefore adequate characterization of these material properties is important when using models to design new experiments. Moukoko et al (2007) developed a rabbit model to characterize the temporal evolution of the structural and mechanical properties of the developing tissues during unloaded endochondral osteogenesis. Some recent studies have looked into other aspects of the higher mentioned uncertainties.…”