Ota Takeru, Chiba Mirei, Hayashi Haruhide
Division of Oral Physiology, Department of Oral Function and Morphology, Graduate School of Dentistry, Tohoku University, 4-1 Seiryo-machi, Aoba-ku, Sendai, Miyagi, 980-8575, Japan.
Cytotechnology. 2016 Dec;68(6):2287-2299. doi: 10.1007/s10616-016-0023-x. Epub 2016 Sep 17.
Vibrational stimulation is an accepted non-invasive method used to improve bone remodeling. However, the underlying mechanisms of this phenomenon remain unclear. In this study, we developed a new vibration-loading system to apply vibrational stimulation to cells based on a previously reported in vivo study. We hypothesized that osteoblasts respond to vibrational strain by expressing osteogenic marker genes, such as alkaline-phosphatase (ALP), Runx2, and Osterix. To test our hypothesis, we developed a vibration-loading system to apply a precise vibrational force to an osteoblast culture on a silicone membrane. The system regulated frequency and acceleration of the vibration, and strain on the silicone membrane culture surface was measured using the strain gauge method. After vibrational stimulation, cellular gene expression was analyzed using real-time polymerase chain reaction. We obtained clear strain signals from the culture surface at vibrational ranges of 1.0-10 m/s acceleration and frequencies of 30, 60, and 90 Hz, respectively. The strain increased in a linear fashion, depending on the acceleration magnitude. Vibrational stimulation also significantly upregulated expression of the osteogenic marker genes Runx2, Osterix, type I collagen, and ALP. In conclusion, we developed a new vibration-loading system that can precisely regulate frequency and acceleration, and we established the presence of dynamic cellular strain on a culture surface. Our findings suggest that vibrational stimulation may directly induce osteoblast differentiation.
振动刺激是一种公认的用于改善骨重塑的非侵入性方法。然而，这一现象的潜在机制仍不清楚。在本研究中，我们基于先前报道的一项体内研究，开发了一种新的振动加载系统，用于对细胞施加振动刺激。我们假设成骨细胞通过表达成骨标记基因（如碱性磷酸酶（ALP）、Runx2和Osterix）来响应振动应变。为了验证我们的假设，我们开发了一种振动加载系统，用于对硅膜上的成骨细胞培养物施加精确的振动力。该系统可调节振动的频率和加速度，并使用应变片法测量硅膜培养表面的应变。振动刺激后，使用实时聚合酶链反应分析细胞基因表达。我们分别在1.0 - 10 m/s加速度的振动范围以及30、60和90 Hz的频率下，从培养表面获得了清晰的应变信号。应变随加速度大小呈线性增加。振动刺激还显著上调了成骨标记基因Runx2、Osterix、I型胶原蛋白和ALP的表达。总之，我们开发了一种能够精确调节频率和加速度的新型振动加载系统，并证实了培养表面存在动态细胞应变。我们的研究结果表明，振动刺激可能直接诱导成骨细胞分化。
