title: Injury response of geriatric mouse patellar tendons.
abstract: Injury adversely impacts the structure and mechanical properties of a tendon, thus causing pain and disability. Previously, we demonstrated that patellar tendons in mature (P150) and aged (P300) mice do not recover original functionality, even 6 weeks after injury, and that uninjured geriatric tendons (P570) are functionally inferior to uninjured mature tendons. In this study, we hypothesized that the repair response in injured geriatric mice would be further compromised, thus undermining patellar tendon function post-injury. Patellar tendons from wild-type mice were injured at 540 days. At 3 and 6 weeks post-surgery, structural, mechanical, and biochemical analyses were performed and compared to uninjured controls. Mechanical properties of geriatric tendons failed to improve after injury. When compared to mature and aged tendons post-injury, it was determined that at no age was there a suitable repair response. In previous studies, we were able to associate the absence of SLRPs with phenotypic changes both early and late in repair. Here we found that SLRPs were significantly decreased after injury, thus offering a possible explanation for why geriatric tendons were unable to mount an adequate repair response. Thus, we conclude that regardless of age after maturity, tendon healing ultimately results in a substandard outcome. © 2015 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 34:1256-1263, 2016.
authors.affiliation: Department of Animal Science, University of California Davis, 2211 Meyer Hall, One Shields Ave, Davis, California, 95616.|Department of Molecular Pharmacology and Physiology, University of South Florida Morsani College of Medicine, 12901 Bruce B. Downs Blvd, MDC 8, Tampa, Florida, 33612.
authors.forename: Michael J
authors.initials: MJ
authors.lastname: Mienaltowski
authors.affiliation: Orthopaedic Research Laboratory, University of Pennsylvania, 424 Stemmler Hall, 3450 Hamilton Walk, Philadelphia, Pennsylvania, 19104.
authors.forename: Andrew A
authors.initials: AA
authors.lastname: Dunkman
authors.affiliation: Orthopaedic Research Laboratory, University of Pennsylvania, 424 Stemmler Hall, 3450 Hamilton Walk, Philadelphia, Pennsylvania, 19104.|Department of Biomedical Engineering, University of Rochester, 321 Goergen Hall, Intercampus Drive, Rochester, New York, 14627.
authors.forename: Mark R
authors.initials: MR
authors.lastname: Buckley
authors.affiliation: Orthopaedic Research Laboratory, University of Pennsylvania, 424 Stemmler Hall, 3450 Hamilton Walk, Philadelphia, Pennsylvania, 19104.
authors.forename: David P
authors.initials: DP
authors.lastname: Beason
authors.affiliation: Department of Molecular Pharmacology and Physiology, University of South Florida Morsani College of Medicine, 12901 Bruce B. Downs Blvd, MDC 8, Tampa, Florida, 33612.
authors.forename: Sheila M
authors.initials: SM
authors.lastname: Adams
authors.affiliation: Department of Molecular Pharmacology and Physiology, University of South Florida Morsani College of Medicine, 12901 Bruce B. Downs Blvd, MDC 8, Tampa, Florida, 33612.
authors.forename: David E
authors.initials: DE
authors.lastname: Birk
authors.affiliation: Orthopaedic Research Laboratory, University of Pennsylvania, 424 Stemmler Hall, 3450 Hamilton Walk, Philadelphia, Pennsylvania, 19104.
authors.forename: Louis J
authors.initials: LJ
authors.lastname: Soslowsky
mesh_terms: D000375:Aging / Q000502:physiology*; D000818:Animals; D005260:Female; D008810:Mice, Inbred C57BL; D017847:Patellar Ligament / Q000293:injuries* / Q000378:metabolism / Q000473:pathology / Q000503:physiopathology; D012038:Regeneration; D000071232:Small Leucine-Rich Proteoglycans / Q000378:metabolism; D013708:Tendon Injuries / Q000378:metabolism / Q000473:pathology / Q000503:physiopathology*
chemical_list: D000071232:Small Leucine-Rich Proteoglycans
keywords: aging; injury; small leucine rich repeat proteoglycans; tendon