Repair of the radial defect of rabbit with polyester/ tricalcium phosphate scaffolds prepared by rapid prototyping technology

Objective： To evaluate the effects of repairing rabbit radial defects with polyester/tricalcium phosphate scaffolds prepared by rapid prototyping technology loaded with bovine bone morphogenetic protein （ bBMP）, and find new carriers for growth factors. Methods： Polyester/tricalcium phosphate scaffolds prepared by rapid prototyping technology loaded with and without bovine BMP were used to repair the 15 mm radial defect in rabbit. Then the results of radiography, histology, scaffolds degrade rates and bone mineral density （BMD） were appraised to examine the effects at the 12th week. Results ： At the 12th week postoperatively, all defects treated with bBMP were radiographically repaired. No radius implanted polyester/tricalcium phosphate scaffolds without bBMP showed radiographic and histological union. At experimental groups, longitudinal alignment of lamellar structure was observed histologically at the 12th week,indicating that remodeling of regenerated bone was complete in different degree. Of the three experimental groups, the bony regeneration and remodeling of callus in poly lactide-co-glycolide/tricalcium phosphate （PLGA/ TCP） group was the best. The BMD values were beyond 70% of normal value at the 12th week while the PLGA/ TCP scaffolds group was the highest, and no abnormalities were observed in the surrounding soft tissue in all groups. Conclusions - Polyester/tricalcium phosphate scaffolds prepared by rapid prototyping technology loaded with bovine BMP can repair a 15 mm radial defect of rabbit. As for the results, the PLGA/TCP scaffold is ideal and better than poly L-lactide-co-D, L-lactide （ PDLLA/TCP ） scaffold, but the ploy L-lactic acid （PLLA/TCP） is not so good for its low degradation rates.