AN IMMUNOCYTOCHEMICAL STUDY OF BONE MORPHOGENETIC PROTEIN IN EXPERIMENTAL FRACTURE HEALING OF THE RABBIT MANDIBLE

A monoclonal antibody raised against bone morphogenetic protein (BMP-McAb) has been used to demonstrate the presence of bone morphogenetic protein(BMP) in experimental fracture healing. Rabbit mandibles were fractured using standardized methods and left to heal for 3, 7, 14, 21 and 24 d, respectively. The avidin-biotin complex (ABC) method demonstrated an accumulation of positively stained primitive mesenchymal cells at the fracture site in the hematoma stage of bone repair. These cells appeared to undergo differentiation into positively-stained chondroblasts and osteoblasts during the phase of callus formation. Undifferentiated mesenchymal cells showed a high positive reactivity in the early post-fracture stages but a much lower reactivity during the remodelling phase.The results of our study suggest that bone inductive processes are accompanied by the presence of BMP in osteoprogenitor cells during fracture healing of the mandible and that BMP may play a significant role in osteogenesis during bone healing.

Strontium doped electrospinning fiber membrane with antibacterial and osteogenic properties prepared by pulse electrochemical method

The osteogenic differentiation and new bone formation are commonly delayed by bacterial infection of orthopedic implants,which is urgent to be resolved quickly in the clinic.The current paper prepared a strontium-doped elec-trospinning fiber membrane with antibacterial and osteogenic properties by pulse electrochemical method.Poly-lactic acid/hydroxyapatite(PLLA/HA)composite fiber substrate was fabricated by electrospinning technology,and strontium doped SrHA/Cu/Polypyrrole(PPy)composite coating was constructed with pulse electrodeposi-tion method on its surface.The strontium doping technique,degradation of Sr^(2+)and Cu^(2+),cellular compatibility,and the antibacterial activity of the fiber membrane were examined.The results revealed that the deposition of phosphorus and calcium on composite fiber was the highest,indicating good biological activity.The release of Sr^(2+)and Cu^(2+)was stable and gradual due to the modulation of PPy.The composite fiber presented excellent antibacterial performance and the antibacterial rate was close to 100%against Staphylococcus aureus and Es-cherichia coli.Furthermore,it is conducive to the adhesion,spread,and proliferation of vascular endothelial cells and osteoblasts,namely outstanding osteogenesis and angiogenesis abilities.In conclusion,the multifunctional PLLA/HA@SrHA/Cu/PPy composite fiber membrane with good antibacterial and osteogenic activity by electro-spinning technology and pulsed electrochemical deposition method provides an effective strategy for the poor bone healing of infected bone defects.