Objective: To investigate and compare the osteogenic potential of three kinds of calcium phosphate ceramic as carriers for recombinant human bone morphogenetic protein-2(rhBMP-2) in vivo.
Methods: BCP ceramics (HA, TCP, HA/TCP) impregnated with rhBMP-2 (experimental groups) and without rhBMP-2(control groups) were implanted into 6 muscles pockets on the dorsum of 3-month-old Wistar rabbits. The rabbits were sacrificed 2, 4 and 8 weeks after implantation and bone induction was estimated by alkaline phosphatase (ALP) activity measurement. The implants were also examined histologically and histomorphometrically by HE staining and computerized graphical analysis.
Results: The ALP activity of implants with rhBMP-2 was higher than that of control groups (P < 0.05), but there was no difference between 2 and 4 weeks in experimental groups. In all experimental groups, the implants exhibited that new bone formation increased with the lapse of time. The amount of new bone formation is more in HA/rhBMP-2 group than in the other two group in the 2nd and 4th weeks, but there was no difference between them (P > 0.05). In the 8th week, the amount of bone formation was most in HA/TCP with rhBMP-2, and was more than that in the 2nd and 4th weeks. Whereas in control groups, there was only fibrous connective tissue.
Conclusion: HA/TCP is a good carriers of rhBMP-2 and can be used as bone substitutes clinically.