| Description |
Ligaments exhibit viscoelastic behavior in response to strain. This behavior protects joints from injury during loading. Collagen is the primary structural component of ligaments, but does not account fully for the viscoelastic behavior. Elastin is another structural protein in ligaments, and provides structural support to the collagen. We investigated the contribution of elastin to the viscoelastic stress relaxation of medial collateral ligaments (MCLs) through the comparison of control MCL with MCL with a digested elastin network. Pancreatic elastase was used to digest the elastin network in treated tissue. Polyethylene glycol (PEG) was used to isolate the effects of water from the effects of elastin on the stress relaxation of the MCLs. The elastase-treated tissues exhibited lower stress responses to elongation versus the control groups. The elastasetreated PEG tissue also showed both an increase in the magnitude of relaxation at every strain step, and an increased rate of strain verses the control PEG tissue. Taken together, these data suggest that elastin exerts a damping force in response to ligament strain, which may shield the collagen from fractures by dissipating stress over time. Additionally, the PBS groups exhibited higher rates and magnitudes of relaxation than the PEG counterparts at low strain levels, suggesting that the effects of water content on stress relaxation are only apparent at low strain levels. |
