Cytobiochemical Study of Periodontal Ligament Fibroblast and Alveolar Bone Cell Derived from Human Periodontium.

趾部，特别是牙周韧带和牙槽骨，是不断受到物理应力的组织，其中包括咬合，咀嚼甚至重力。这些因素是这些组织细胞代谢的内在因素。Saito等人最近报道了人牙周韧带成纤维细胞（HPLF）的碱性磷酸酶（ALPase）表现出与成骨细胞相似的非常高的活性，并提出HPLF可以被称为“成骨成纤维细胞”。(1) HPLF上合成的ALPase与1,25(OH)_2 D_3有关，通过DNA含量和^3H-TdR的掺入测定，D_3降低了细胞的生长。SDS-PAGE上分离的ALPase活性鉴定为110K和120-130K。经胰蛋白酶处理后，未被D_3改变的110K ALPase转化为100K，释放10K肽。这个110K的ALPase可能与细胞膜结构紧密相关。SDS-PAGE显示，120 ~ 130k的ALPase被D_3显著提高，并被胰蛋白酶完全消化。在培养的HPLF中，ALPase可能不仅位于质膜上，而且位于细胞外基质中。因此，调节骨内Ca^2代谢的D_3可能控制HPLF的细胞周期和ALPase基因表达。(2)机械应力对细胞生长和分化的影响应力条件培养基（S-CM）比非应力条件培养基（NS-CM）更显著地降低HPLF、HGF和HABC细胞层的蛋白质含量。NE-CM和S-CM分别使HPLF的ALPase活性提高1.71倍和2.63倍。与S-CM孵育的DNA中^3H-TdR的掺入被显著抑制。另一方面。S-CM刺激细胞接种和粘附后的细胞扩散。其中一个细胞扩散因子的分子大小估计为10K肽，它是热不稳定的，被蛋白水解酶消化。因此，机械应力可能调节HPLF的细胞代谢，刺激负性细胞自分泌生长因子的分泌，而负性细胞自分泌生长因子本身可能控制细胞反应。少

The petiodantium, especially the periodontal ligament and alveolar bone, are tissues constantly subjected to physical stresses among which are occlusion, mastication and even gravity. These factors are inherent factors in the metabolism of these tissue cells. Saito et al recently reported that the alkaline phosphatase(ALPase) of human periodontal ligament fibroblasts(HPLF) showed remarkably high activity which was similar to that present in asteoblasts, and suggested that HPLF could be tersed as " osteoblastic fibroblast".(1) ALPase synthesized on HPLF in relation to 1,25(OH)_2 D_3The cell growth which was assayed by DNA contents and the incorporation of ^3H-TdR was decreased by D_3 From the separation of ALPase activity on SDS-PAGE, 110K and 120-130K ALPase were identified. The 110K ALPase, which was not changed by D_3, was converted to 100K, releasing 10K peptide after trypsin treatment. This 110K ALPase might be tightly associated with cell membrane structure. The 120-130K ALPase wa … More s remarkably increased by D_3 on SDS-PAGE and completely digested with trypsin. The ALPase in the cultured HPLF might be located not only on the plasma membrane but also in the extracellular matrix.Therefore, D_3, which regulates Ca^2 metabolism in bone, may control the cell cycle and also the gene expression of ALPase of HPLF.(2) Effects of mechanical stress on the cell growth and differentiationThe protein content of cell layers of HPLF, HGF and HABC were more significantly decreased by stressed conditioned medium(S-CM) than by non-stressed conditioned medium(NS-CM). ALPase activity of HPLF was increased 1.71 fold by NE-CM and 2.63 fold by S-CM. The incorporation of ^3H-TdR into DNA incubated with S-CM was remarkably inhibited. On the other hand. S-CM stimulated cell spreading after cell inoculation and adhesion. The molecular size of one of the cell spreading factors was estimated 10K peptide which is heat labile and digested by proteolytic enzymes.Therefore, mechanical stress may regulate cell metabolism of HPLF, stimulating secretion of a negative cellular autocrine growth factor, which might itself control cellular response. Less