Department of Chemical and Biomolecular Engineering, University of Nebraska, Lincoln, NE 68516, USA.
Cells Tissues Organs. 2013;197(1):14-26. doi: 10.1159/000339772. Epub 2012 Sep 11.
The impact of low-intensity diffuse ultrasound (LIDUS) stimulation on the cytoskeletal organization of chondrocytes seeded in three-dimensional (3D) scaffolds was evaluated. Chondrocytes seeded on 3D chitosan matrices were exposed to LIDUS at 5.0 MHz (approx. 15 kPa, 51 s, 4 applications/day) in order to study the organization of actin, tubulin and vimentin. The results showed that actin presented a punctate cytosolic distribution and tubulin presented a quasiparallel organization of microtubules, whereas vimentin distribution was unaffected. Chondrocytes seeded on 3D scaffolds responded to US stimulation by the disruption of actin stress fibers and were sensitive to the presence of Rho-activated kinase (ROCK) inhibitor (Y27632). The gene expression of ROCK-I, a key element in the formation of stress fibers and mDia1, was significantly upregulated under the application of US. We conclude that the results of both the cytoskeletal analyses and gene expression support the argument that the presence of punctate actin upon US stimulation was accompanied by the upregulation of the RhoA/ROCK pathway.
研究了低强度弥散超声（LIDUS）刺激对三维（3D）支架中接种的软骨细胞细胞骨架组织的影响。为了研究肌动蛋白、微管蛋白和波形蛋白的组织，将软骨细胞接种在 3D 壳聚糖基质上，然后用 5.0 MHz（约 15 kPa，51 s，每日 4 次）的 LIDUS 进行处理。结果表明，肌动蛋白呈现点状细胞质分布，微管蛋白呈现准平行的微管组织，而波形蛋白的分布不受影响。接种在 3D 支架上的软骨细胞通过破坏肌动蛋白应力纤维对 US 刺激作出反应，并且对 Rho 激活激酶（ROCK）抑制剂（Y27632）敏感。在应用 US 时，ROCK-I 的基因表达（形成应力纤维的关键要素）和 mDia1 显著上调。我们得出结论，细胞骨架分析和基因表达的结果都支持这样的观点，即在 US 刺激下点状肌动蛋白的存在伴随着 RhoA/ROCK 通路的上调。
