RESUMO
Poor fixation of bone replacement implants, e.g. the artificial hip, in implantation sites with inferior bone quality and quantity may be overcome by the use of implants coated with a cultured living bone equivalent. In this study, we tested, respectively, amorphous carbonated apatite (CA)- and crystalline octacalcium phosphate (OCP)-coated discs for their use in bone tissue engineering. Subcultured rat bone marrow cells were seeded on the substrates and after 7 days of culture, the implants were subcutaneously implanted in nude mice for 4 weeks. After 7 days of culture, the cells had formed a continuous multi-layer that covered the entire surface of the substrates. The amount of cells was visually higher on the crystalline OCP-coated discs compared to the amorphous CA-coated discs. Furthermore, the amorphous CA-coated discs exhibited a visually higher amount of mineralized extracellular matrix compared to the crystalline OCP-coated discs. After 4 weeks of implantation, clear de novo bone formation was observed on all discs with cultured cells. The newly formed bone on the crystalline OCP-coated discs was more organized and revealed a significantly higher volume compared to the amorphous CA-coated discs. The percentage of bone contact with the discs was also significantly higher on the OCP-coated discs. Overall, the results suggest that a crystalline OCP coating is more suitable for bone tissue engineering than an amorphous CA coating.
