A description of the rate of contraction‐relaxation of rat tail tendons

Abstract

AbstractAging alters the contraction‐relaxation of rat tail tendons; this has been attributed to an increase in the degree of crosslinking of collagen and its surrounding mucopoly‐saccharides. An analysis was made of tendon mechanics after acetic acid exposure in the untreated and formaldehyde treated state as well as the properties of acetic acid–water solutions. Tendons were treated with formaldehyde solutions (pH 7–8) over a wide range of dilution (100,000: 1 to 1: 1, pF = 5 to 0) of a stock 37% formalin. The contraction‐relaxation and extractability were followed after exposure to 0.5M acetic acid. An empirical analysis of the length vs. time curves yielded the initial rate of contraction, dL/dtC, the rate of relaxation, dL/dtR, and a specifie rate constant for the process, KCR. There was a parallent dependence of formaldehyde concentration on the effect of incurbes as well as the exteractability of tendons. On the length‐vs.‐time curves as well as the extractability of tendons. This was interpreted as evidence of the effect of induced crosslinking on the properties of the macromolecule collagen. Since similar effects are observed as a function of natural aging the role of added crosslinking as the mechanism for this change is suggested again. Contimuous variation analyses of spectroscopic and viscometric data of the acetic spectroscopic and viscometric data of the acetic acid–water system demonstrated extensive molecular interaction. The hydrogen bond‐forming tendencies of the carboxyl CO and HO may be as the basis for the action of the solvent in the contraction‐relaxation process.