A novel MRI compatible mouse fracture model to characterize and monitor bone regeneration and tissue composition

Abstract

Over the last years, murine in vivo magnetic resonance imaging (MRI) contributed to a new understanding of tissue composition, regeneration and diseases. Due to artefacts generated by the currently used metal implants, MRI is limited in fracture healing research so far. In this study, we investigated a novel MRI-compatible, ceramic intramedullary fracture implant during bone regeneration in mice. Three-point-bending revealed a higher stiffness of the ceramic material compared to the metal implants. Electron microscopy displayed a rough surface of the ceramic implant that was comparable to standard metal devices and allowed cell attachment and growth of osteoblastic cells. MicroCT-imaging illustrated the development of the callus around the fracture site indicating a regular progressing healing process when using the novel implant. In MRI, different callus tissues and the implant could clearly be distinguished from each other without any artefacts. Monitoring fracture healing using MRI-compatible implants will improve our knowledge of callus tissue regeneration by 3D insights longitudinal in the same living organism, which might also help to reduce the consumption of animals for future fracture healing studies, significantly. Finally, this study may be translated into clinical application to improve our knowledge about human bone regeneration.

Dynamic in vivo monitoring of fracture healing process in response to magnesium implant with multimodal imaging: pilot longitudinal study in a rat external fixation model

“…Specialized sequences may be used to partially address the problem, and dynamic MRI with multiple sequences could be realized by using non-metallic screws. 70 Still, the authors suggest a preemptive MRI test to check if the implant material to be tested could be another source of artifact. Further details of potential applications and extensions of the current model are listed in Fig.…”

Angiogenesis is uncoupled from osteogenesis during calvarial bone regeneration

“…the left leg was fractured with three-point bending. It was stabilized with an intramedullary nail (hollow needle 23 G) as described previously 81 . Carprofen (4 mg/kg intra muscular) was given as an analgesic and further on at 24-hour intervals when required.…”