Tensile Properties of Cultured Aortic Smooth Muscle Cells Obtained in a quasi-in situ Tensile Test with Thermoresponsive Gelatin

摘要

References(31) Cited-By(5) We established a quasi-in situ tensile test to measure the tensile properties of smooth muscle cells (SMCs) cultured on substrate maintaining their shape and cytoskeletal integrity. SMCs were cultured on a substrate coated with thermoresponsive gelatin (PNIPAAm-gelatin) and were held with a pair of micropipettes coated with an adhesive. Cells were detached from the substrate by lowering ambient temperature to dissolve the PNIPAAm-gelatin. Tensile tests for fusiform SMCs up to ∼15% strain performed 3 times in normal and Ca2+-free Hank's balanced salt solution (HBSS(+) and HBSS(-), respectively) in order to investigate the effects of Ca2+ on the change in their tensile properties during loading/unloading cycles. The stiffness of the fusiform SMCs obtained by the first loading process in HBSS(-) and in HBSS(+) was 0.041±0.024 N/m (n=6, mean±SEM) and 0.031±0.008 N/m (n=6), respectively, and was significantly lower than that of spherical cells detached from the substrate by trypsinization (∼0.09 N/m), indicating that cell stiffness is overestimated when cells are trypsinized. Cell stiffness increased from the first cycle to the second and then stabilized in HBSS(-), while it increased continuously with the number of the cycles in HBSS(+). These results suggest that the mechanical properties of SMCs change with stretching and that extracellular Ca2+ has a significant effect on their response to stretch.