Abstract:

BACKGROUND: Allogenic bone marrow mesenchymal stem cells as seed cells for tissue engineering have become the future trend of development.
OBJECTIVE: To investigate the osteogenic effects of allogenic bone marrow mesenchymal stem cells and the outcome in vivo.
METHODS: Bone marrow mesenchymal stem cells from beagle dogs were marked with chloromethylbenzoyl ammonia fluorescent dye (CM-Dil), and the proliferation of labeled cells was measured using MTT assay in vitro. Autologous or allogenic bone marrow mesenchymal stem cells were inoculated into coral and β-tricalcium phosphate scaffolds for 7 days osteogenic induction and then subcutaneously implanted into the back of beagle dogs. Dogs undergoing blank scaffold implantation served as negative controls. Hematoxylin-eosin staining was used to observe new bone formation at 3 days, 1, 2, 4, 8, 12 weeks after surgery. Bone formation area was statistically analyzed using ipp software. In the CM-Dil group, frozen sections were made to trace the in vivo outcome of bone marrow mesenchymal stem cells under a fluorescence microscope.
RESULTS AND CONCLUSION: The osteogenesis speed in the allogenic bone tissue engineering group was faster than that in the autologous bone tissue engineering group at 4-8 weeks after implantation, but no significant difference between the two groups was found beginning at the 12th week. At 4 weeks after implantation, the expression of γ-carboxy glutamic acid protein in the autologous bone tissue engineering group was higher than that in the allogenic bone tissue engineering group, prompting the bone mineralization appeared earlier in the latter group than the former one. ELISA results showed that the expression of alkaline phosphatase and osteocalcin in the autologous bone tissue engineering group was higher than that in the allogenic bone tissue engineering group at 4 weeks after implantation, and then the expression showed no difference at 12 weeks. CM-Dil labeling results showed that the number of allogenic bone marrow mesenchymal stem cells was reduced significantly compared with that of autologous bone marrow mesenchymal stem cells. All these findings indicate that the ectopic osteogenesis of the allogenic tissue-engineered bone in large animals is found within 12 weeks after implantation, but the osteogenesis efficiency at early stage (within 8 weeks) is lower compared with the autologous tissue-engineered bone. This difference may be related to the post-implantation immunoreactions that lead to the reduction in cell number.

中国组织工程研究杂志出版内容重点：组织构建；骨细胞；软骨细胞；细胞培养；成纤维细胞；血管内皮细胞；骨质疏松；组织工程

Key words: Tissue engineering, Mesenchymal Stem cells, Transplantation, Homologous, Stents