Influence of Decorin and Biglycan on Tensile Viscoelastic Properties in Knockout Mice

Abstract

Tendons have a complex, viscoelastic mechanical behavior that depends on their composition and structure. Understanding these structure-function relationships may help elucidate important differences in the varying functional behaviors of specific tendons as well as guide targeted treatment modalities and tissue engineered constructs. The tendon extracellular matrix (ECM) can be described as a biocomposite material consisting of collagen fibers surrounded by an extrafibrillar matrix. Many studies have focused on the role of the fibers on the tensile properties of tendon; however, fibers alone do not completely explain the viscoelastic and non-linear response of tendon. The interactions of small leucine-rich proteoglycans (SLRPs) with other ECM molecules, such as collagen fibrils, as well as their association with water suggest that SLRPs may play a role in tendon viscoelasticity. Some studies have assessed the role of SLRPs or glycosaminoglycans in the mechanical response of tendon, but few have explored their role in more sophisticated viscoelastic properties. Therefore, the objective of this study was to evaluate the viscoelastic response of the patellar tendon in two different SLRP knockout mice compared to wildtype. We hypothesized that the absence of SLRPs would lead to a stiffer dynamic tissue response compared to wildtype.