International Journal of Cell Biology / 2012 / Article / Fig 3

Research Article

Effects of Substrate Mechanics on Contractility of Cardiomyocytes Generated from Human Pluripotent Stem Cells

Figure 3

Contraction stress of cardiomyocytes increased with substrate stiffness; bead displacement and beating rate did not increase with stiffness. (a) Average contraction stress of neonatal rat, D30 H9-derived, and D30 19-9-11-derived cardiomyocytes increased with substrate stiffness. Each data point represents an average of the absolute values of contraction stresses over area for a single cell at the maximum point of its contraction cycle. Mean contraction stress values were significantly affected by stiffness via one-way ANOVA (overall for rat and overall for D30 H9 and D30 19-9-11). ***( ) and *( ) indicate statistically significant differences relative to neonatal rat cardiomyocytes on the same stiffness. (b) Maximum contraction stress of neonatal rat, D30 H9-derived, and D30 19-9-11-derived cardiomyocytes increased with substrate stiffness. Each data point represents the upper limit of the range of contraction stresses generated by a single cell at the maximum point of its contraction cycle. ***( ) and ( ) indicate statistically significant differences relative to neonatal rat and D30 19-9-11-derived cardiomyocytes, respectively, on the same stiffness. (c) Displacement of fluorescent beads occurred to a similar extent on all stiffnesses. Each data point represents an average of the absolute values of bead displacement for a single cell, including both near- and far-field beads. For all cell lines, substrate stiffness significantly affected bead displacement using one-way ANOVA (overall , , for rat, D30 H9, and D30 19-9-11 resp.), with an overall significant decreasing (rat and D30 H9) or nonsignificant increasing (D30 19-9-11) trend via linear regression. (d) Beating rate was similar on all stiffnesses. Substrate stiffness did not significantly affect beating rate via one-way ANOVA for each cell line (overall , , for rat, D30 H9, and D30 19-9-11, resp.). For (a)–(d), cells for each stiffness and error bars represent SEM.
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