Vascular tissue exhibits marked mechanical nonlinearity when exposed to large strains. Vascular smooth muscle cells (VSMCs) are the most prevalent cell type in the artery wall, but it is unclear how much of the vessel nonlinearity is attributable to VSMCs. Here, we used cellular microbiaxial stretching (CμBS) to measure the large-strain mechanical properties of individual VSMCs. We find that the mechanical properties of VSMCs with native-like architectures are highly anisotropic, due to their highly aligned actomyosin cytoskeletons, and that inhibition of actomyosin contraction with rho-associated kinase inhibitor HA-1077 results in nearly isotropic material properties. We further find that when VSMCS are exposed to large strains (up to 60% stretch), the cells’ stress–strain behavior is surprisingly linear. Finally, we modified a previously published Holzapfel-Gasser-Ogden type strain energy density function to characterize individual VSMCs, to account for the observed large-deformation linearity. These data have important implications in the development of models of vascular mechanics and mechanobiology.

当暴露于大应变时，血管组织表现出明显的机械非线性。血管平滑肌细胞（VSMC）是动脉壁中最普遍的细胞类型，但尚不清楚多少血管非线性可归因于VSMC。在这里，我们使用细胞微双轴拉伸（CμBS）来测量单个VSMC的大应变力学性能。我们发现具有天然样结构的VSMC的机械性能具有高度各向异性，这是由于其高度对齐的放线菌素细胞骨架，并且用rho-associated激酶抑制剂HA-1077抑制放线菌素的收缩导致了几乎各向同性的材料性能。我们进一步发现，当VSMCS暴露于大应变（拉伸率高达60％）时，细胞的应力应变行为出乎意料地呈线性。最后，我们修改了以前发布的Holzapfel-Gasser-Ogden型应变能密度函数来表征单个VSMC，以解决观察到的大变形线性问题。这些数据对血管力学和力学生物学模型的发展具有重要意义。