ABSTRACT
PURPOSE: To explore the ectopic osteogenic abilities of bone marrow stromal cells (BMSCs) on different scaffold materials in nude mice. METHODS: Canine BMSCs in vitro cultured were seeded at the density of 1x10(6)cells/cm(2) onto scaffolds of freeze-dried demineralized bone matrix (fdDBM), tricalcium phosphate (TCP), 200microm coralline hydroxyapatite (CH200) and 500microm coralline hydroxyapatite (CH500). The cell adherence and growth on the materials were examined by SEM and H&E staining after 4 to 7 days of in vitro culturing. To observe the ectopic osteogenic capacity, four 10mmx5mmx2mm cell/scaffold complexes (fdDBM, TCP, CH200, CH500) and a blank control scaffold (fdDBM only) were implanted subcutaneously into each of athymic mice (n=8). The implants were harvested after 9 weeks and H&E stained. Newly formed trabecular bone volume (TBV) was measured by IMAGER-PRO PLUS software, and statistical analysis was performed by ANOVA with SAS software. RESULTS: Canine BMSCs adhered to all 4 types of scaffolds and spread well in their pores 7-8 days after seeding. Athymic subcutaneous ectopic osteogenesis were observed in all the specimens of TCP, CH200, CH500 but were observed only in 75% of BMSCs/fdDBM and 25% of fdDBM. The TCP group showed significant higher TBV percentage (28.2%+/-2.86) than CH200 group (24.1%+/-4.12) and CH500 group (18.1%+/-4.66) (P<0.01). CONCLUSIONS: BMSCs adhered to all 4 scaffolds. When combined with BMSCs, TCP exhibited the greatest osteogenic potential, which indicates that it might be an excellent scaffold material in the field of bone tissue engineering. Supported by National 973 Project (G1999054300) and National Natural Science Foundation of China(30271426).