In Vitro Experimental and Numerical Simulation Study on the Influence of Uniaxial Cyclic Compression on Cytoskeletal Structure.

While research on cellular responses to cyclic compression has predominantly focused on proliferation and differentiation, changes in cell orientation and force distribution within the cytoskeleton represent crucial biomechanical aspects that remain less explored. This study aimed to design a programmable device for applying uniaxial cyclic compression to cells and analyze actin filament reorientation following specific compression regimens. A programmable device was developed to apply uniaxial cyclic compression. A finite element model of a viscoelastic cell incorporating actin filaments was developed to evaluate cell membrane strain. Statistical analysis included Pearson correlation to assess the relationship between actin filament orientation and membrane strain, following normality confirmation with the Kolmogorov-Smirnov test. Student's t-test and one-way ANOVA were used to assess significance between groups. A strong positive correlation was found between the average/peak maximum principal strain on the cell membrane and the angle of actin filaments relative to the cell long axis (r = 0.96, p < 0.05; r = 0.94, p < 0.05, respectively). Cyclic compression reduced the maximum principal strain by reversing the actin filament orientation observed under static compression. This correlated with a significant decrease in cell mortality. Cyclic compression reduces the maximum principal strain on the cell membrane via reorientation of actin filaments, suggesting a cytoprotective effect. These findings provide insight into biomechanical adaptive mechanisms of cells under cyclic compression and could inform the design of bioreactors and rehabilitation devices.