Basic Study of Suitable Condition for Bone Formation by Human Osteoblasts and Clinical Application

为了根据成骨细胞在生长和改建过程中的成骨机制开发与成骨细胞结合的骨替代物，必须使从骨髓中获得的分化的成骨细胞产生骨组织。本研究探讨了体外培养人成骨细胞向成骨细胞分化的适宜条件及体内成骨能力，结果表明：在10 - 10 μ M Dex中培养6天的人成骨细胞碱性磷酸酶（ALP）活性<-8><-6>呈剂量依赖性增加。10 μ <-7>M Dex处理3-9天后ALP活性呈时间依赖性增加。成骨细胞分化的生化指标，包括ALP活性和I型前胶原羧基末端肽和骨钙素的分泌，在10 μ M的地塞米松<-7>处理5天后显著增强。在单层培养中，成骨细胞的矿化也受到B的刺激 关于我们 此外，在存在或不存在10 μ M Dex的情况下，将人成骨细胞培养在由变性I型胶原组成的胶原海绵中<-7>。将这些细胞沿着胶原海绵一起移植到SCID小鼠中，并在2-8周收获移植物。在2-4周时，Dex处理的成骨细胞的移植物形成骨样组织，其数量以时间依赖性方式增加至8周。这种骨样组织由移植细胞新合成的矿化胶原基质组成。在类骨组织周围的移植细胞中检测到较高的ALP活性和骨钙素表达。超微结构上，这种矿化基质与骨相似。单纯移植未处理的细胞和胶原海绵不能形成骨样组织。这些研究表明，Dex处理的成骨细胞通过类似骨形成机制的过程在体内形成骨样组织，提示培养的成骨细胞在生长和重塑过程中是基于骨形成机制的，可用作骨替代物。少

For the development of the bone substitutes combined with osteblats on the basis of the mechanism of bone formation during growth and remodeling, it is indispensable to make the differentiated osteoblastic cells obtained from bone marrow produce bone tissue. In this study, we evaluated the suitable condition for the differentiation into osteoblast and the capacity for in vivo bone formation of cultured human osteoblastic cells.The alkaline phosphatase (ALP) activity of the cells cultured for 6 days in 10^<-8>-10^<-6>M Dex increased in a dose-dependent manner. Furthermore, an increase of ALP activity by 10^<-7>M Dex treatment for 3-9 days was observed in a time-dependent manner. Biochemical indicators of osteoblastic differentiation, which include ALP activity and secretion of procollagen type I carboxy-terminal peptide and osteocalcin, were significantly enhanced by Dex treatment at 10^<-7>M for 5 days. In monolayr culture, mineralization by the osteoblastic cells was also stimulated b … More y Dex treatement.Furthermore, human osteoblastic cells were cultured within collagen sponge, which consists of denatured type I collagen, in the presence or absence of 10^<-7>M Dex. These cells along with collagen sponge were transplanted into the SCID mice, and the transplants were harvested at 2-8 weeks. At 2-4 weeks, the transplants of Dex-treated osteoblastic cells formed bone-like tissue, the quantity of which increased in a time-dependent manner to 8 weeks. This bone-like tissue was composed of mineralized collagen matrix newly synthesized by the transplanted cells. A higher expression of ALP activity and osteocalcin was detected in the transplanted cells surrounding the bone-like tissue. Ultrastructurally, this mineralized matrix was similar to bone. The transplants of non-treated cells and collagen sponge alone failed to from bone-like tissue. Thses studies indicate that the bone-like tissue is formed in vivo by the Dex-treated osteoblastic cells via the process resembled mechanism of bone formation, suggesting that the cultured osteoblastic cells is useful as a bone substitutes on the basis of the mechanism of bone formation during growth and remodeling. Less