Ecole Polytechnique, Laboratory for Optics and Biosciences, 91128 Palaiseau, France.
J Biomech. 2011 Jul 28;44(11):2047-52. doi: 10.1016/j.jbiomech.2011.05.009. Epub 2011 Jun 1.
We continuously monitored the microstructure of a rat-tail tendon during stretch/relaxation cycles. To that purpose, we implemented a new biomechanical device that combined SHG imaging and mechanical testing modalities. This multi-scale experimental device enabled simultaneous visualization of the collagen crimp morphology at the micrometer scale and measurement of macroscopic strain-stress response. We gradually increased the ultimate strain of the cycles and showed that preconditioning mostly occurs in the first stretching. This is accompanied by an increase of the crimp period in the SHG image. Our results indicate that preconditioning is due to a sliding of microstructures at the scale of a few fibrils and smaller, that changes the resting length of the fascicle. This sliding can reverse on long time scales. These results provide a proof of concept that continuous SHG imaging performed simultaneously with mechanical assay allows analysis of the relationship between macroscopic response and microscopic structure of tissues.
我们在拉伸/松弛循环过程中持续监测鼠尾肌腱的微观结构。为此，我们开发了一种新的生物力学设备，将 SHG 成像和力学测试模式结合在一起。这种多尺度实验设备使我们能够在微米尺度上同时可视化胶原卷曲形态，并测量宏观应变-应力响应。我们逐渐增加循环的极限应变，结果表明预处理主要发生在第一次拉伸过程中。这伴随着 SHG 图像中卷曲周期的增加。我们的结果表明，预处理是由于少数原纤维和更小的微观结构的滑动，改变了束的静止长度。这种滑动可以在长时间尺度上反转。这些结果证明了一个概念，即同时进行连续 SHG 成像和力学检测可以分析宏观响应与组织微观结构之间的关系。
