title: Genetic Response of Rat Supraspinatus Tendon and Muscle to Exercise.
abstract: Inflammation is a complex, biologic event that aims to protect and repair tissue. Previous studies suggest that inflammation is critical to induce a healing response following acute injury; however, whether similar inflammatory responses occur as a result of beneficial, non-injurious loading is unknown. The objective of this study was to screen for alterations in a subset of inflammatory and extracellular matrix genes to identify the responses of rat supraspinatus tendon and muscle to a known, non-injurious loading condition. We sought to define how a subset of genes representative of specific inflammation and matrix turnover pathways is altered in supraspinatus tendon and muscle 1) acutely following a single loading bout and 2) chronically following repeated loading bouts. In this study, Sprague-Dawley rats in the acute group ran a single bout of non-injurious exercise on a flat treadmill (10 m/min, 1 hour) and were sacrificed 12 or 24 hours after. Rats in the chronic group ran 5 days/wk for 1 or 8 weeks. A control group maintained normal cage activity. Supraspinatus muscle and tendon were harvested for RNA extractions, and a custom Panomics QuantiGene 2.0 multiplex assay was used to detect 48 target and 3 housekeeping genes. Muscle/tendon and acute/chronic groups had distinct gene expression. Components of the arachidonic acid cascade and matrix metalloproteinases and their inhibitors were altered with acute and chronic exercise. Collagen expression increased. Using a previously validated model of non-injurious exercise, we have shown that supraspinatus tendon and muscle respond to acute and chronic exercise by regulating inflammatory- and matrix turnover-related genes, suggesting that these pathways are involved in the beneficial adaptations to exercise.
authors.affiliation: McKay Orthopaedic Research Laboratory, University of Pennsylvania, Philadelphia, Pennsylvania, United States of America.
authors.forename: Sarah Ilkhanipour
authors.initials: SI
authors.lastname: Rooney
authors.affiliation: Molecular Profiling Core, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, United States of America.
authors.forename: John W
authors.initials: JW
authors.lastname: Tobias
authors.affiliation: McKay Orthopaedic Research Laboratory, University of Pennsylvania, Philadelphia, Pennsylvania, United States of America.
authors.forename: Pankti R
authors.initials: PR
authors.lastname: Bhatt
authors.affiliation: McKay Orthopaedic Research Laboratory, University of Pennsylvania, Philadelphia, Pennsylvania, United States of America.
authors.forename: Andrew F
authors.initials: AF
authors.lastname: Kuntz
authors.affiliation: McKay Orthopaedic Research Laboratory, University of Pennsylvania, Philadelphia, Pennsylvania, United States of America.
authors.forename: Louis J
authors.initials: LJ
authors.lastname: Soslowsky
mesh_terms: D000818:Animals; D003094:Collagen / Q000378:metabolism; D008297:Male; D020782:Matrix Metalloproteinases / Q000378:metabolism; D018482:Muscle, Skeletal / Q000378:metabolism; D010805:Physical Conditioning, Animal; D025341:Principal Component Analysis; D012313:RNA / Q000302:isolation & purification / Q000378:metabolism; D051381:Rats; D017207:Rats, Sprague-Dawley; D013710:Tendons / Q000378:metabolism*; D059467:Transcriptome
chemical_list: D012313:RNA; D003094:Collagen; D020782:Matrix Metalloproteinases