Nagatomi Jiro, Arulanandam Bernard P, Metzger Dennis W, Meunier Alain, Bizios Rena
Department of Biomedical Engineering, Rensselaer Polytechnic Institute, Troy, NY 12180-3590, USA.
Ann Biomed Eng. 2003 Sep;31(8):917-23. doi: 10.1114/1.1590663.
In an attempt to elucidate the cellular/molecular correlations between mechanical stimuli and new bone formation, the present in vitro study used a custom-made laboratory setup and examined the effects of cyclic pressure on select functions of osteoblasts pertinent to osteogenesis. The results demonstrated that, compared to controls (no pressure), mRNA expression for type-I collagen (the main constituent of the organic phase of bone) was enhanced when osteoblasts were exposed to cyclic pressure (10-40 kPa at 1.0 Hz) for 1 h daily for up to 19 consecutive days. In addition, compared to controls, both deposition of collagen and accumulation of calcium (one of the major components of the inorganic phase of bone) increased significantly (p<0.05) following exposure of osteoblast cultures to cyclic pressure for 19 days. Since the amounts of total DNA in controls and in osteoblast cultures exposed to cyclic pressure were similar at all time points tested, it was concluded that increased collagen and calcium concentrations in cultures resulted from enhanced osteoblast function (and not from increased number of cells); the presence of increased amounts of collagen affected the subsequent increased accumulation of calcium. These results provide evidence that daily exposure to cyclic pressure for various time periods (up to 19 days) affect osteoblast functions pertinent to bone formation.
为了阐明机械刺激与新骨形成之间的细胞/分子关联，本体外研究使用了定制的实验室装置，并检测了循环压力对成骨细胞与骨生成相关的特定功能的影响。结果表明，与对照组（无压力）相比，当成骨细胞每天暴露于循环压力（1.0 Hz下10 - 40 kPa）1小时，持续19天时，I型胶原蛋白（骨有机相的主要成分）的mRNA表达增强。此外，与对照组相比，成骨细胞培养物暴露于循环压力19天后，胶原蛋白沉积和钙（骨无机相的主要成分之一）积累均显著增加（p<0.05）。由于在所有测试时间点，对照组和暴露于循环压力的成骨细胞培养物中的总DNA量相似，因此得出结论，培养物中胶原蛋白和钙浓度的增加是由于成骨细胞功能增强（而非细胞数量增加）；胶原蛋白量的增加影响了随后钙积累的增加。这些结果提供了证据，表明每天在不同时间段（长达19天）暴露于循环压力会影响与骨形成相关的成骨细胞功能。
