Role of Bone Marrow Derived Autologous Mesenchymal Stem Cells in Fracture Healing in Rabbits

In 10-20% of the fractures, the fracture healing process is impaired which leads to non union and delayed union [1, 2]. Such factors have led to the quest for modalities which can enhance fracture healing. Fracture healing takes place through various stages as hematoma formation, inflammation, angiogenesis, callus formation, and bone remodeling. The healing cascade is coordinated by the interaction of different set of molecules with the local and circulating cells i.e. mitogens (TGF B), Insulin like growth factor (IGF), morphogens (BMPs), effectors of inflammation(IL-1 , IL-6, COX -2), fibroblast growth factor(FGF), platelet derived growth factor(PGDF) and angiogenic factors(VEGF and angiopoietins). These factors affect the proliferation and differentiation of MSCs [3]. MSCs are the pluripotent mesodermal cells which have the potential to differentiate into the different tissues. In the presence of the lineage specific growth factors these MSC have been induced to differentiate into bone in tissue culture [4, 5]. The fracture repair process is initiated by the Mesenchymal stem cells which results in the formation of callus i.e. cartilaginous template .This callus is thereafter replaced by the new bone which repairs the gap[6]. In various experimental studies it has been