Bone cell responses to high-frequency vibration stress: does the nucleus oscillate within the cytoplasm?
Bone cell responses to high-frequency vibration stress: does the nucleus oscillate within the cytoplasm?
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DOI：
10.1096/fj.05-4966.com
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发表时间：
2006-05-01
期刊：
影响因子：
4.8
通讯作者：
Klein-Nulend, Jenneke
中科院分区：
文献类型：
--
作者：
Bacabac, Rommel G.;Smit, Theo H.;Klein-Nulend, Jenneke
细胞的机械感测指导骨量和结构的变化，以响应机械负荷的挑战。低幅、高频率负荷通过促进骨形成和抑制废用性骨质疏松来刺激骨生长。然而，骨细胞如何感知振动应力是未知的。因此，我们研究了骨细胞对宽频率范围（5-100 Hz）振动应力的反应。我们使用NO和前列腺素E（2）（PGE（2））释放以及考克斯-2 mRNA表达作为骨细胞反应的参数，因为这些分子调节骨对机械负荷的适应。NO的释放与振动应力的最大加速度呈正相关，而PGE 2的释放与振动应力的最大加速度呈负相关。考克斯-2 mRNA表达以频率依赖性方式增加，这与高频率下NO释放增加有关，证实了我们先前的结果。NO和PGE 2的释放呈负相关，表明这些信号分子在骨适应高频负荷中发挥不同的作用。最大加速度速率与ω（3）（频率= ω/2 π）成比例，这与用于模拟由于振动应力引起的细胞质内的细胞核运动的斯托克斯-爱因斯坦关系相称。NO和PGE（2）与最大加速度速率的相关性则与核振荡有关，为高频负荷的细胞机械感测提供了物理基础。
Mechanosensing by cells directs changes in bone mass and structure in response to the challenges of mechanical loading. Low-amplitude, high-frequency loading stimulates bone growth by enhancing bone formation and inhibiting disuse osteoporosis. However, how bone cells sense vibration stress is unknown. Hence, we investigated bone cell responses to vibration stress at a wide frequency range (5-100 Hz). We used NO and prostaglandin E(2) (PGE(2)) release, and COX-2 mRNA expression as parameters for bone cell response since these molecules regulate bone adaptation to mechanical loading. NO release positively correlated whereas PGE2 release negatively correlated to the maximum acceleration rate of the vibration stress. COX-2 mRNA expression increased in a frequency-dependent manner, which relates to increased NO release at high frequencies, confirming our previous results. The negatively correlated release of NO and PGE2 suggests that these signaling molecules play different roles in bone adaptation to high-frequency loading. The maximum acceleration rate is proportional to omega(3) (frequency = omega/2 pi), which is commensurate with the Stokes-Einstein relation for modeling cell nucleus motion within the cytoplasm due to vibration stress. Correlations of NO and PGE(2) with the maximum acceleration rate then relate to nucleus oscillations, providing a physical basis for cellular mechano-sensing of high-frequency loading.