Quantification of the mechanical behavior of carotid arteries from wild-type, dystrophin-deficient, and sarcoglycan-delta knockout mice.

As patients with muscular dystrophy live longer because of improved clinical care, they will become increasingly susceptible to many of the cardiovascular diseases that affect the general population. There is, therefore, a pressing need to better understand both the biology and the mechanics of the arterial wall in these patients. In this paper, we use nonlinear constitutive relations to model, for the first time, the biaxial mechanical behavior of carotid arteries from two common mouse models of muscular dystrophy (dystrophin-deficient and sarcoglycan-delta null) and wild-type controls. It is shown that a structurally motivated four-fiber family stress-strain relation describes the passive behavior of all three genotypes better than does a commonly used phenomenological exponential model, and that a Rachev-Hayashi model describes the mechanical contribution of smooth muscle contraction under basal tone. Because structurally motivated constitutive relations can be extended easily to model adaptations to altered hemodynamics, results from this study represent an important step toward the ultimate goal of understanding better the mechanobiology and pathophysiology of arteries in muscular dystrophy.