异体脱钙骨基质骨粒复合骨水泥骨缺损修复材料结构特征及生物力学性能

AIM: To analyze constructive and biomechanical properties of different quality ratio material impregnated decalcified bone matrix (DBM) with bone cement (BC) . METHODS: The DBM particles and the materials impregnated 0 rmg/g, 300 mg/g and 400 mg/g maas ratio DBM particles with BC were made according to the methods of Urist et al. The compound material constructions were observed by scanning electron microscope and the biomechanical properties were measured by Instron mechanics testing-machine. RESULTS: The DBM particles with irregular gaps existing within interspace were connected with BC by the multipoint mode in the compound material. The ultimate compressive strength were 0 mg/g DBM in (59.3 ±2.2) MPa, 300 mg/g in (27.1 ±1.8) MPa, 400 mg/g in (19.3±1.6) MPa. The ultimate bending strength were 0 mg/g in (54.3±3.7) MPa, 300 mg/g in (18.5±1.1) MPa, 400 mg/g in (13.3±1.4) MPa. CONCLUSION: The materials of DBM impregnated with BC had perfect plastic property with much more irregular gaps existing within interspace. The materials could provide abundant biomechanical support.

Objective To express the recombinant human bone morphogenetic protein-7 (rhBMP-7) in Chinese hamster ovary (CHO) cells and to establish the in vitro biological activity assay of rhBMP-7. Methods Human BMP-7 cDNA was subcloned into pcDNA3.1 mammalian expression vector and transfected to CHO cells by using the lipofectin transfection method. BMP-7 expression cell culture supernatants were harvested and purified for target protein. To analyze the bioactivity of the secreted rhBMP-7, a novel in vitro assay was established by measuring its alkaline phosphatase (ALP) stimulating of osteoblast cell line, W-20-17. Results BMP-7 stably expressing cell clone was selected, which secreted mature disulfide-linked homodimer form of hBMP-7 and had an apparent molecular weight of 36kDa. rhBMP-7 with ＞95% purity was obtained using 3 step chromatography method. Bioactivity assay showed that the purified protein specifically stimulated W-20-17 cell producing ALP, with a 4-fold increase of ALP activity at 100ng/ml or more, and the EC50 of 15.6ng/ml. Conclusion Purified rhBMP-7 from this CHO expression system has significant biological activity in induction of osteoblast phenotype, which demonstrates potential bone regeneration activity.