Experimental study of subcutaneous osteogenesis by bone marrow stromal cells with A-PCPC in Beagle dogs

PURPOSE:To study the osteogenic capability of the construct combined dog's bone stromal cells with active porous calcium phosphate cement(A-PCPC) in nude mice in vivo.METHODS:Isolated bone marrow stromal cells(BMSCs) were expanded and osteogenically induced in vitro.Their osteogenic phenotype was evaluated by cytochemistry.The tissue engineering complex was constructed with BMSCs/A-PCPC in vitro.After SEM scanning,the complex of BMSCs/A-PCPC was implanted into the subcutaneous tissue of the nude mice as experimental group,and A-PCPC as control group.The engineered bone was harvested 2,4,8weeks post-implantation and processed for HE staining,then evaluated by histology and histomorphometry.RESULTS:Cytochemistry showed alkaline phosphate activity,Von Kossa staining proved the formation of mineralization nodules.Scanning electron microscopy showed the cells adhered to the inner surface of the A-PCPC.HE staining showed a small group of woven bone formation 2 weeks later in the experimental group,while the formation of bone less in the control group.Woven bone turned into trabecular bone gradually at 4 weeks in the experimental group,while the control group showed a large number of bone-like tissue.Histomorphometry showed more mature bone in the experimental group than the control group at 8 weeks.CONCLUSIONS:The A-PCPC/BMSCs composites show good osteogenetic activity and could promote mineralization of the immature bone.It can be used as the bone tissue engineering scaffolds.