Effects of scaffold stiffness on mechanosensitivity of cultured cardiac myocytes

Abstract

We have been studying adverse effect of ultrasound exposure on pulsation of the heart using cardiomyocytes isolated from neonatal rats. Our previous study used cardiac myocytes cultured on a cover slip scaffold; however, the stiffness of the underlying layer is very different from that in in vivo conditions. In this study, cardiomyocytes were cultured on a soft gel scaffold, and their mechanosensitivity was compared with those cultured on a coverslip scaffold. In the experimental results, significant difference was found in the shape indices that represent circularity of cells (gel, 0.29 ± 0.08; cover slip, 0.11 ± 0.04), indicating that cytoskeleton is less developed in the cells cultured on the gel scaffold. Furthermore, a threshold of cycle numbers to induce pulsation disruption is about 10 times higher in the cardiomyocytes culltured on gel scaffold, suggesting the dependence of mechanosensitivity of cardiomyocytes on development of their cytoskeleton.