Komarova S V, Ataullakhanov F I, Globus R K
Life Sciences Division, NASA Ames Research Center, Moffett Field, California 94035-1000, USA.
Am J Physiol Cell Physiol. 2000 Oct;279(4):C1220-9. doi: 10.1152/ajpcell.2000.279.4.C1220.
To evaluate the relationship between osteoblast differentiation and bioenergetics, cultured primary osteoblasts from fetal rat calvaria were grown in medium supplemented with ascorbate to induce differentiation. Before ascorbate treatment, the rate of glucose consumption was 320 nmol. h(-1). 10(6) cells(-1), respiration was 40 nmol. h(-1). 10(6) cells(-1), and the ratio of lactate production to glucose consumption was approximately 2, indicating that glycolysis was the main energy source for immature osteoblasts. Ascorbate treatment for 14 days led to a fourfold increase in respiration, a threefold increase in ATP production, and a fivefold increase in ATP content compared with that shown in immature cells. Confocal imaging of mitochondria stained with a transmembrane potential-sensitive vital dye showed that mature cells possessed abundant amounts of high-transmembrane-potential mitochondria, which were concentrated near the culture medium-facing surface. Acute treatment of mature osteoblasts with metabolic inhibitors showed that the rate of glycolysis rose to maintain the cellular energy supply constant. Thus progressive differentiation coincided with changes in cellular metabolism and mitochondrial activity, which are likely to play key roles in osteoblast function.
为了评估成骨细胞分化与生物能量学之间的关系，将培养的来自胎鼠颅骨的原代成骨细胞在添加了抗坏血酸的培养基中培养以诱导分化。在抗坏血酸处理之前，葡萄糖消耗速率为320 nmol·h⁻¹·10⁶细胞⁻¹，呼吸作用为40 nmol·h⁻¹·10⁶细胞⁻¹，乳酸产生与葡萄糖消耗的比率约为2，这表明糖酵解是未成熟成骨细胞的主要能量来源。与未成熟细胞相比，抗坏血酸处理14天导致呼吸作用增加四倍，ATP产生增加三倍，ATP含量增加五倍。用跨膜电位敏感的活性染料对线粒体进行共聚焦成像显示，成熟细胞拥有大量高跨膜电位的线粒体，这些线粒体集中在面向培养基的表面附近。用代谢抑制剂对成熟成骨细胞进行急性处理表明，糖酵解速率上升以维持细胞能量供应恒定。因此，渐进性分化与细胞代谢和线粒体活性的变化同时发生，这可能在成骨细胞功能中起关键作用。
