Eearly Bone Repair and Regeneration of Nano-Sized J3-Tricalcium Phosphates/Collagen Composite in Rabbits

A novel biomimetic composite consisted of nano P-tricalcium phosphate and collagen (n-TCP/Col.), having similar structure with the natural bone, was produced by a wet-chemical method. The biological effect with and without n-TCP/Col on bone repair and regeneration was evaluated by histological and radiological examination in a rabbit femoral condyle model. The results showed that radiopacity of implant decreased gradually and began to increase at 12 weeks, while no obvious changes for the control. Histological results revealed that trabecular bone formed around the implant at 4 weeks and increased at 8 weeks; By 12 weeks, bone filling with Harvard's system was observed around the implant. By contrast, only loose connective tissue was seen in control group. This was further illuminated by fluorescence microscopy. The results of this study suggested that the novel nano p-tricalcium phosphate and collagen composite possessed good properties of osteoconductivity and degradation in the biological environment, which could have potential application as a promising bone substitute.