Porous calcium phosphate cement induces osteogenesis of mesenchymal stem cells under microenvironment / 中国组织工程研究

ABSTRACT

BACKGROUND: The osteoinduction by biomaterials has been proven in various animal experiments. OBJECTIVE: To investigate the osteoinduction of porous calcium phosphate cement on bone marrow mesenchymal stem cel s. METHODS: Bone marrow mesenchymal stem cel s were isolated from rabbits aged 1 week in vitro and labeled by PKH-67 or PKH-26, respectively. Forty-eight adult New Zealand white rabbits were randomized into four groups and porous calcium phosphate cement was implanted into both sides of gluteus maximus in each rabbit. Then, 1 mL PKH-26-labeled bone barrow mesenchymal stem cel s (1×1010/L) were injected into the superior gluteal artery branch at each side of gluteus maximus near the femur, and 1 mL PKH-67-labeled bone barrow mesenchymal stem cel s (1×1010/L) injected into tissues around the cement (group A); 1 mL PKH-26-labeled bone barrow mesenchymal stem cel s (1×1010/L) were injected into the each side of superior gluteal artery branch (group B); 1 mL PKH-67-labeled bone barrow mesenchymal stem cel s (1×1010/L) were injected into tissues around the cement (group C); the same amount of normal saline was injected into tissues around the cement (group D). At 3, 7 and 12 weeks after implantation, the cement and its surrounding tissues were extracted and detected by fluorescence microscope and Massion staining. Expression of bone morphogenetic protein 2 was analyzed by RT-PCR. RESULTS AND CONCLUSION: Under fluorescence microscope, PKH-26-labeled bone barrow mesenchymal stem cel s attached fast and distributed homogeneously; however, PKH-67-labeled bone barrow mesenchymal stem cel s attached slowly and exhibited a gradual y homogeneous distribution. Massion staining showed that ectopic new bone formation appeared to have an upward trend in al groups, and the area of new bones in groups A, B and C were larger than that of group D at different time points after implantation. There was a significantly higher expression of bone morphogenetic protein 2 in groups A, B and C compared with the group D at different time points after implantation (P < 0.05), and the expression was the highest in the group A (P < 0.05). In conclusion, the porous calcium phosphate cement can induce bone barrow mesenchymal stem cel s chemotaxis and osteogenetic differentiation. Besides, osteoblasts are differentiated from both the surrounding capil aries and body fluid, and capil ary-derived mesenchymal stem cel s occupy the important position.