title: The injury response of aged tendons in the absence of biglycan and decorin.
abstract: Recent studies have demonstrated that the small leucine-rich proteoglycans (SLRPs) biglycan and decorin impact tendon development, aging and healing in mature mice. However, despite the increased risk of tendon injury in the elderly, the role of SLRPs in tendon repair has not been investigated in aged animals. Therefore, our objective was to elucidate the influences of bigylcan and decorin on tendon healing in aged mice to relate our findings to previous work in mature mice. Since the processes of aging and healing are known to interact, our hypothesis was that aging mediates the role of biglycan and decorin on tendon healing. Patellar tendons from wild-type, biglycan-null and decorin-null mice were injured at 270 days using an established model. At 3 and 6 weeks post-surgery, structural, mechanical and biochemical analyses were performed and compared to uninjured controls. Early stage healing was inferior in biglycan-null and decorin-null mice as compared to wild type. However, tendons of all genotypes failed to exhibit improved mechanical properties between 3 and 6 weeks post-injury. In contrast, in a previous investigation of tendon healing in mature (i.e., 120 day-old) mice, only biglycan-null mice were deficient in early stage healing while decorin-null mice were deficient in late-stage healing. These results confirm that the impact of SLRPs on tendon healing is mediated by age and could inform future age-specific therapies for enhancing tendon healing.
authors.affiliation: The McKay Orthopaedic Research Laboratory, University of Pennsylvania, 424 Stemmler Hall, 3450 Hamilton Walk, Philadelphia, PA 19104, USA.
authors.forename: Andrew A
authors.initials: AA
authors.lastname: Dunkman
authors.affiliation: The McKay Orthopaedic Research Laboratory, University of Pennsylvania, 424 Stemmler Hall, 3450 Hamilton Walk, Philadelphia, PA 19104, USA.
authors.forename: Mark R
authors.initials: MR
authors.lastname: Buckley
authors.affiliation: Department of Molecular Pharmacology & Physiology, University of South Florida Morsani College of Medicine, 12901 Bruce B. Downs Blvd, MDC 8, Tampa, FL 33612, USA.
authors.forename: Michael J
authors.initials: MJ
authors.lastname: Mienaltowski
authors.affiliation: Department of Molecular Pharmacology & Physiology, University of South Florida Morsani College of Medicine, 12901 Bruce B. Downs Blvd, MDC 8, Tampa, FL 33612, USA.
authors.forename: Sheila M
authors.initials: SM
authors.lastname: Adams
authors.affiliation: The McKay Orthopaedic Research Laboratory, University of Pennsylvania, 424 Stemmler Hall, 3450 Hamilton Walk, Philadelphia, PA 19104, USA.
authors.forename: Stephen J
authors.initials: SJ
authors.lastname: Thomas
authors.affiliation: The McKay Orthopaedic Research Laboratory, University of Pennsylvania, 424 Stemmler Hall, 3450 Hamilton Walk, Philadelphia, PA 19104, USA.
authors.forename: Akash
authors.initials: A
authors.lastname: Kumar
authors.affiliation: The McKay Orthopaedic Research Laboratory, University of Pennsylvania, 424 Stemmler Hall, 3450 Hamilton Walk, Philadelphia, PA 19104, USA.
authors.forename: David P
authors.initials: DP
authors.lastname: Beason
authors.affiliation: Department of Pathology, Anatomy & Cell Biology, Thomas Jefferson University, 1020 Locust Street, Jefferson Alumni Hall, Suite 249, Philadelphia, PA 19107, USA.
authors.forename: Renato V
authors.initials: RV
authors.lastname: Iozzo
authors.affiliation: Department of Molecular Pharmacology & Physiology, University of South Florida Morsani College of Medicine, 12901 Bruce B. Downs Blvd, MDC 8, Tampa, FL 33612, USA.
authors.forename: David E
authors.initials: DE
authors.lastname: Birk
authors.affiliation: The McKay Orthopaedic Research Laboratory, University of Pennsylvania, 424 Stemmler Hall, 3450 Hamilton Walk, Philadelphia, PA 19104, USA. Electronic address: soslowsk@upenn.edu.
authors.forename: Louis J
authors.initials: LJ
authors.lastname: Soslowsky
mesh_terms: D000375:Aging / Q000473:pathology / Q000502:physiology*; D000818:Animals; D058578:Biglycan / Q000235:genetics / Q000378:metabolism*; D001696:Biomechanical Phenomena; D017931:DNA Primers / Q000235:genetics; D058575:Decorin / Q000235:genetics / Q000378:metabolism*; D005260:Female; D051379:Mice; D008810:Mice, Inbred C57BL; D008822:Mice, Transgenic; D046529:Microscopy, Electron, Transmission; D017847:Patellar Ligament / Q000293:injuries; D020133:Reverse Transcriptase Polymerase Chain Reaction; D013708:Tendon Injuries / Q000378:metabolism*; D014945:Wound Healing / Q000235:genetics / Q000502:physiology*
chemical_list: C546885:Bgn protein, mouse; D058578:Biglycan; D017931:DNA Primers; C546879:Dcn protein, mouse; D058575:Decorin
keywords: Aging; Biglycan; Decorin; Injury; Proteoglycan; Tendon