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.
Bibliographical noteFunding Information:
We acknowledge our funding sources US National Science Foundation (CMMI 1553255, PWA), the American Heart Association (16PRE27770112, ZW), and the University of Minnesota Graduate College of Science and Engineering Fellowship (TMR). Portions of this work were conducted in the Minnesota Nano Center, which is supported by the National Science Foundation through the National Nano Coordinated Infrastructure Network (NNCI) under Award Number ECCS-1542202.
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