Annals of Biomedical Engineering ( IF 3.8 ) Pub Date : 2020-09-21 , DOI: 10.1007/s10439-020-02615-9 Amin Komeili 1, 2 , Baaba Sekyiwaa Otoo 1 , Ziad Abusara 1, 3 , Scott Sibole 1 , Salvatore Federico 1, 4 , Walter Herzog 1, 5
Dynamic deformation of chondrocytes are associated with cell mechanotransduction and thus may offer a new understanding of the mechanobiology of articular cartilage. Despite extensive research on chondrocyte deformations for static conditions, work for dynamic conditions remains rare. However, it is these dynamic conditions that articular cartilage in joints are exposed to everyday, and that seem to promote biological signaling in chondrocytes. Therefore, the objective of this study was to develop an experimental technique to determine the in situ deformations of chondrocytes when the cartilage is dynamically compressed. We hypothesized that dynamic deformations of chondrocytes vastly differ from those observed under steady-state static strain conditions. Real-time chondrocyte geometry was reconstructed at 10, 15, and 20% compression during ramp compressions with 20% ultimate strain, applied at a strain rate of 0.2% s−1, followed by stress relaxation. Dynamic compressive chondrocyte deformations were non-linear as a function of nominal strain, with large deformations in the early and small deformations in the late part of compression. Early compression (up to about 10%) was associated with chondrocyte volume loss, while late compression (> ~ 10%) was associated with cell deformation but minimal volume loss. Force continued to decrease for 5 min in the stress-relaxation phase, while chondrocyte shape/volume remained unaltered after the first minute of stress-relaxation.
中文翻译:
轻度动态载荷条件下的软骨细胞变形。
软骨细胞的动态变形与细胞机械转导有关,因此可能为关节软骨的机械生物学提供新的理解。尽管对静态条件下的软骨细胞变形进行了广泛的研究,但动态条件下的工作仍然很少见。然而,关节中的关节软骨每天都暴露在这些动态条件下,并且似乎促进了软骨细胞中的生物信号传导。因此,本研究的目的是开发一种实验技术来确定原位当软骨被动态压缩时软骨细胞的变形。我们假设软骨细胞的动态变形与在稳态静态应变条件下观察到的有很大不同。实时软骨细胞几何形状在斜坡压缩期间以 10%、15% 和 20% 压缩重建,极限应变为 20%,应变率为 0.2% s -1,然后是应力松弛。动态压缩软骨细胞变形作为名义应变的函数是非线性的,在压缩的早期变形较大,在压缩后期变形较小。早期压缩(高达约 10%)与软骨细胞体积损失有关,而晚期压缩(> ~ 10%)与细胞变形有关,但体积损失最小。在压力放松阶段,力量继续减少 5 分钟,而在压力放松的第一分钟后,软骨细胞的形状/体积保持不变。