title: Compression loading in vitro regulates proteoglycan synthesis by tendon fibrocartilage.
abstract: The regulation of proteoglycan synthesis in a fibrocartilaginous tissue by mechanical loading was assessed in vitro. Discs of bovine tendon fibrocartilage were loaded daily with unconfined, cyclic, uniaxial compression (5 s/min, 20 min/day) and the synthesis of large and small proteoglycans was measured by incorporation of [35S]sulfate. All discs synthesized predominantly large proteoglycan when first placed in culture. After 2 weeks in culture nonloaded discs synthesized predominantly small proteoglycans whereas loaded discs continued to produce predominantly large proteoglycan. The turnover of 35S-labeled proteoglycan was not significantly altered by the compression regime. Increased synthesis of large proteoglycans was induced by a 4-day compression regime following 21 days of culture without compression. Inclusion of cytochalasin B during compression mimicked this induction. Autoradiography demonstrated that cell proliferation was minimal and confined to the disc edges whereas 35S-labeled proteoglycan synthesis occurred throughout the discs. These experiments demonstrate that mechanical compression can regulate synthesis of distinct proteoglycan types in fibrocartilage.
authors.affiliation: Department of Biology, University of New Mexico, Albuquerque 87131.
authors.forename: T J
authors.initials: TJ
authors.lastname: Koob
authors.forename: P E
authors.initials: PE
authors.lastname: Clark
authors.forename: D J
authors.initials: DJ
authors.lastname: Hernandez
authors.forename: F A
authors.initials: FA
authors.lastname: Thurmond
authors.forename: K G
authors.initials: KG
authors.lastname: Vogel
mesh_terms: D000818:Animals; D002356:Cartilage / Q000378:metabolism*; D002417:Cattle; D046508:Culture Techniques; D011509:Proteoglycans / Q000096:biosynthesis*; D013314:Stress, Mechanical; D013710:Tendons / Q000378:metabolism*; D013997:Time Factors
chemical_list: D011509:Proteoglycans