Influence of Physical Forces on Progenitor Cell Migration, Proliferation and Differentiation in Fracture Repair

摘要

The goal of this program is to investigate the influence of controlled mechanical stimulation on the behavior of progenitor cells in an effort to develop strategies to significantly enhance the rate and quality of fracture repair in long bone. All of the proposed studies in the program were completed. The results demonstrate that the application of load increases the callus volume, bone mineral density and biomechanical properties. More importantly, the data demonstrates a substantial independence on the time of load application. Load stimulation can positively influence fracture repair when applied at 10 or 24 days after fracture, while early application (during granulation tissue formation) may be detrimental to tissue regeneration. We also demonstrated that systemically introduced progenitor cells play an indirect role on the repair and identified a variety of factors that may be associated with repair cell recruitment. Surprisingly, the introduction of cells locally into the fracture site were detrimental to the repair process and unaffected by load. The results provide a rationale for new strategies for enhancing fracture repair.