Eklou-Kalonji E, Denis I, Lieberherr M, Pointillart A
Laboratoire de Nutrition et Sécurité Alimentaire, INRA 78 352 Jouy-en-Josas cedex, France.
Cell Tissue Res. 1998 Apr;292(1):163-71. doi: 10.1007/s004410051046.
We examined the effects of various extracellular calcium concentrations on DNA content, procollagen type I carboxy-terminal propeptide (PICP) release (reflects type I collagen synthesis), and alkaline phosphatase activity of porcine osteoblasts. Osteoblasts seeded in control medium (2.2 mM calcium) were transferred to low (0. 5 or 1 mM) calcium medium or to high (3, 5, 7, or 10 mM) calcium medium at different stages of the culture period and for different incubation times. When osteoblasts were transferred to low or high (3 or 5 mM) calcium medium 1 or 2 days after plating and kept in that medium until the end of the culture period, PICP release was inhibited, but DNA content and alkaline phosphatase activity were unchanged, except in 5 mM calcium, which inhibited alkaline phosphatase activity. Short-term culture of subconfluent and near-confluent osteoblasts in 7 or 10 mM calcium for 48 h inhibited DNA content. DNA content returned to normal levels when cells were transferred back to control medium, whereas alkaline phosphatase inhibition induced by 5, 7, or 10 mM calcium was not reversible. Short-term culture in high calcium media did not affect PICP release. Thus, in porcine osteoblasts, low and high extracellular calcium concentrations affect DNA content, PICP release, and the expression of osteoblastic phenotype markers (alkaline phosphatase activity). These effects are dependent on the duration of calcium treatment and the state of differentiation of the osteoblasts.
我们研究了不同细胞外钙浓度对猪成骨细胞DNA含量、I型前胶原羧基末端前肽（PICP）释放（反映I型胶原合成）以及碱性磷酸酶活性的影响。接种于对照培养基（钙浓度为2.2 mM）中的成骨细胞在培养期的不同阶段以及不同孵育时间被转移至低钙（0.5或1 mM）培养基或高钙（3、5、7或10 mM）培养基中。当成骨细胞在接种后1天或2天被转移至低钙或高钙（3或5 mM）培养基并在该培养基中培养至培养期结束时，PICP释放受到抑制，但DNA含量和碱性磷酸酶活性未发生变化，不过在5 mM钙浓度下，碱性磷酸酶活性受到了抑制。亚汇合和接近汇合的成骨细胞在7或10 mM钙中短期培养48小时会抑制DNA含量。当细胞转回对照培养基时，DNA含量恢复至正常水平，而5、7或10 mM钙诱导的碱性磷酸酶抑制作用是不可逆的。在高钙培养基中短期培养不影响PICP释放。因此，在猪成骨细胞中，低细胞外钙浓度和高细胞外钙浓度会影响DNA含量、PICP释放以及成骨细胞表型标志物（碱性磷酸酶活性）的表达。这些影响取决于钙处理的持续时间和成骨细胞的分化状态。
