Fig. 1.

Desmin knockout (des^−/−) fibers from young muscle were more compliant compared with wild type (wt). A: passive Cauchy stress-sarcomere length quadratic curve fits for young wt (n = 17) and des^−/− (n = 14) fibers. Aa: neonatal mice. Ab: young mice. Ac: adult mice. Although raw data were fit with quadratic regression, fiber stress-sarcomere length curves were nearly linear. Young des^−/− fibers had significantly lower stress compared with wt at sarcomere lengths >3.7 μm as determined by ANOVA with repeated measures. B: tangent moduli calculated from curve fits at a sarcomere length of 3.9 μm for des^−/− and wt fibers in 3 age groups. Young des^−/− fibers were significantly more compliant compared with wt. However, there was no difference between neonatal or adult fiber stiffness values with genotype. *P < 0.05.