Stirbat Tomita Vasilica, Tlili Sham, Houver Thibault, Rieu Jean-Paul, Barentin Catherine, Delanoë-Ayari Hélène
Institut Lumière Matière, UMR5306 Université de Lyon 1-CNRS, Université de Lyon, 69622 Villeurbanne cedex, France.
Eur Phys J E Soft Matter. 2013 Aug;36(8):84. doi: 10.1140/epje/i2013-13084-1. Epub 2013 Aug 12.
Morphogenetic processes involve cell flows. The mechanical response of a tissue to active forces is linked to its effective viscosity. In order to decouple this mechanical response from the complex genetic changes occurring in a developing organism, we perform rheometry experiments on multicellular aggregates, which are good models for tissues. We observe a cell softening behavior when submitting to stresses. As our technique is very sensitive, we were able to get access to the measurement of a yield point above which a creep regime is observed obtained for strains above 12%. To explain our rheological curves we propose a model for the cytoskeleton that we represent as a dynamic network of parallel springs, which will break under stress and reattach at null strain. Such a simple model is able to reproduce most of the important behavior of cells under strain. We highlight here the importance of considering cells as complex fluids whose properties will vary with time according to the history of applied stress.
形态发生过程涉及细胞流动。组织对主动力的力学响应与其有效粘度相关。为了将这种力学响应与发育中的生物体中发生的复杂基因变化解耦，我们对多细胞聚集体进行流变学实验，多细胞聚集体是组织的良好模型。我们观察到在施加应力时细胞会出现软化行为。由于我们的技术非常灵敏，我们能够测量到一个屈服点，超过该点，对于应变高于12%的情况会观察到蠕变状态。为了解释我们的流变曲线，我们提出了一个细胞骨架模型，将其表示为平行弹簧的动态网络，该网络在应力作用下会断裂，并在零应变时重新连接。这样一个简单的模型能够重现细胞在应变下的大多数重要行为。我们在此强调将细胞视为复杂流体的重要性，其性质会根据所施加应力的历史随时间而变化。
