Celluar Biological Analysis on the Mechanism of Mineralization of Human Bone Tissue and its Application for Reconstruction of Human Tissue in Vitro

用胶原凝胶包埋的方法从人上颌骨中分离出成骨细胞。对分离细胞的培养和鉴定结果表明，细胞对PTH和PGE_2有反应，分泌骨钙素，单层培养形成矿化区。当我们研究了几种因素对细胞分化和增殖的影响时，骨基质中含有的血小板源性生长因子倾向于刺激细胞的增殖。据报道，骨髓组织中含有可分化为成骨细胞和成软骨细胞的细胞。由此，我们培养了骨髓基质细胞，阐明了组织中存在成骨细胞，并在体外形成矿化结节。对结节进行组织学和免疫组织化学分析。在这些细胞中，证实存在不需要-甘油磷酸酯就能矿化的细胞。由于软骨细胞在骨形成中具有重要作用，我们也对其进行了研究。我们在单层培养中获得终分化的软骨细胞。维甲酸有刺激细胞增殖的倾向。结果表明，维甲酸对软骨细胞增殖的作用机制不是由表皮生长因子介导的，而是由蛋白激酶c介导的。维甲酸在培养的软骨细胞胞浆和细胞核中均有结合能力。这些结合能力被认为与维甲酸的作用机制有关。此外，为了更深入地了解软骨内成骨的生理机制，我们研究了低钙饮食对生长大鼠下颌软骨的影响。结果提示，生长大鼠缺钙及随后的代谢紊乱导致增生细胞区细胞增殖受到抑制，软骨细胞成熟受到抑制，细胞外基质钙化不良导致软骨吸收受到抑制，从而抑制髁突正常软骨内成骨，抑制髁突软骨内生长。少

Osteoblastic cells were isolated from human maxilla by embedding the bone pieces in collagen gel. As a result of the culture and characterization of the isolated cells, the cells responded to PTH and PGE_2, secreted osteocalcin and formed mineralized area in monolayer culture. When we investigated the effect of several factors on differentiation and proliferation of the cells, platelet-derived growth factor contained in the bone matrix tended to stimulate proliferation of the cells.Bone marrow tissue is reported to contain cells which can differentiate to osteoblast and chondroblast. From these facts, we cultured bone marrow stromal cells and elucidated that the tissue has osteogenic cells, which formed mineralized nodules in vitro. The nodules were analyzed histologically and immunohistochemically. Among the cells, it is confirmed to exist the cells which could mineralize without beta-glycerophosphate.As chondrocytes have an important role in bone formation, we have also studied the f … More ollowing research. We obtained terminally differentiated chondrocytes in monolayer culture. The cells tended to be stimulated proliferation by retinoic acid. The results suggested that the mechanism of proliferation by retinoic acid was not mediated by epidermal growth factor but by protein kinase C. The retinoic acid binding capacity was detected in both the cytosol and nuclear of the cultured chondrocytes. These binding capacity was supposed to be involved in the mechanism of retinoic acid.Furthermore, in order to obtain more insight into the physiologic mechanism of endochondral ossification, changes occurring in the mandibular cartilage of growing rats fed on a low-calcium diet were investigated. The results indicated that calcium-deficiency and subsequent metabolic disorder in growing rats induced inhibition of cell proliferation in the proliferative cell zone, inhibition of maturation of chondrocytes, and inhibition of cartilage resorption due to poor calcification of the extracellular matrix, so that the mechanism of normal endocondral ossification might be inhibited and enibited and endochondral growth of mandibular condyle by suppressed. Less