A kinetic analysis of swelling of rat tail tendon

Abstract

AbstractInteraction of water with connective tissue is an important biophysical process. The chemical and physical morphology of tendons is a complex syncitium of collagen (procollagen + collastromin), mucopolysaccharide (aqueous phase + dense phase), and water (free and bound). It is proposed that a kinetic analysis of swelling of tendons might add new facts concerning the properties of the above tissue system. The present study shows that although diffusion may be the transport basis for swelling, there exists an anomalous dependence of diffusion on time of swelling. It is proposed that the velocity of swelling (dW/dt) is equal to a term Ks(A/W − BW), the latter embodying a specific rate constant Ks, a driving factor A, and a retardation factor B which relates transitory tendon weight W to the initial weight W0, the equilibrium weight W∞ and time t. When this equation is integrated, a working expression is obtained that agrees satisfactorily with experimental data. It is supported further by theories of swelling of anisotropic gels. Data plotted in the form of log (W2∞ − W2)/(W2∞ − W20) versus t showed good agreement with linearity required by the above rate equation. Longitudinal stress decreased swelling ratio W∞/W0, but sped up attainment of equilibrium.