title: Mechanical, compositional, and structural properties of the mouse patellar tendon with changes in biglycan gene expression.
abstract: Tendons have complex mechanical properties that depend on their structure and composition. Some studies have assessed the role of small leucine-rich proteoglycans (SLRPs) in the mechanical response of tendon, but the relationships between sophisticated mechanics, assembly of collagen and SLRPs have not been well characterized. In this study, biglycan gene expression was varied in a dose dependent manner using biglycan null, biglycan heterozygote and wild type mice. Measures of mechanical (tension and compression), compositional and structural changes of the mouse patellar tendon were evaluated. Viscoelastic, tensile dynamic modulus was found to be increased in the biglycan heterozygous and biglycan null tendons compared to wild type. Gene expression analyses revealed biglycan gene expression was closely associated in a dose-dependent allelic manner. No differences were seen between genotypes in elastic or compressive properties or quantitative measures of collagen structure. These results suggest that biglycan, a member of the SLRP family, plays a role in tendon viscoelasticity that cannot be completely explained by its role in collagen fibrillogenesis.
authors.affiliation: McKay Orthopaedic Research Laboratory, University of Pennsylvania, 424 Stemmler Hall 36th Street and Hamilton Walk, Philadelphia, Pennsylvania 19104-6081, USA.
authors.forename: Leann M
authors.initials: LM
authors.lastname: Dourte
authors.forename: Lydia
authors.initials: L
authors.lastname: Pathmanathan
authors.forename: Michael J
authors.initials: MJ
authors.lastname: Mienaltowski
authors.forename: Abbas F
authors.initials: AF
authors.lastname: Jawad
authors.forename: David E
authors.initials: DE
authors.lastname: Birk
authors.forename: Louis J
authors.initials: LJ
authors.lastname: Soslowsky
mesh_terms: D000818:Animals; D058578:Biglycan / Q000172:deficiency / Q000235:genetics* / Q000378:metabolism; D001696:Biomechanical Phenomena; D003094:Collagen; D004195:Disease Models, Animal; D055119:Elastic Modulus; D004548:Elasticity; D005260:Female; D015870:Gene Expression; D020869:Gene Expression Profiling; D005838:Genotype; D006579:Heterozygote; D051379:Mice; D018345:Mice, Knockout; D017847:Patellar Ligament / Q000378:metabolism / Q000473:pathology* / Q000503:physiopathology*; D012212:Rheology / Q000379:methods; D013314:Stress, Mechanical; D013718:Tensile Strength; D014783:Viscosity
chemical_list: C546885:Bgn protein, mouse; D058578:Biglycan; D003094:Collagen
keywords: biglycan knockout; proteoglycans; structure-function; tendon mechanics