title: Sex-based difference in Achilles peritendinous levels of matrix metalloproteinases and growth factors after acute resistance exercise.
abstract: Several recent investigations have demonstrated that the ability of various tendons to alter structural and functional properties in response to exercise are muted in women compared with men. We hypothesize that this disparity between men and women may be due to a reduced tendon production of key mediators of tendon extracellular matrix (ECM) remodeling in response to mechanical loading, e.g., exercise. Using microdialysis before and after an acute bout of resistance exercise, we evaluated Achilles peritendinous levels of insulin-like growth factor-1 (IGF-1) and interleukin-6 (IL-6), which have both been shown to increase tendon collagen synthesis. Additionally, the matrix remodeling enzymes matrix metalloproteinase-2 (MMP-2), MMP-9, and tissue inhibitor of metalloproteinase-1 (TIMP-1) were also evaluated. IGF-1 levels were elevated (P< 0.05) to a similar extent in men and women after 3 h of exercise but remained elevated at 4 h in only women. IL-6 levels were ~4-fold greater after exercise in both men and women (P< 0.05). MMP-2 levels increased to a similar extent (~2-3-fold) in men and women (P< 0.05). In contrast, MMP-9 increased with exercise but only in men (P< 0.05). Last, TIMP-1 levels also increased (P< 0.05) with exercise in men and women but the increase was more prolonged in women. In conclusion, we observed modest sex differences in tendon release of MMP-9, TIMP-1, and IGF-1 after acute resistance exercise. If such differences persist throughout a chronic exercise training, they may contribute to the reduced ability of women to adapt to exercise compared with men.NEW & NOTEWORTHYIn this investigation we utilized microdialysis of the peritendinous Achilles to evaluate potential differences between men and women in tendon production of key regulators of extracellular matrix remodeling. We demonstrate that a modest sex-specific difference exists in peritendinous levels of several key extracellular matrix modulators after an acute bout of resistance exercise.
authors.affiliation: Department of Physiology, Arizona College of Osteopathic Medicine, Midwestern University, Glendale, Arizona.
authors.forename: Broc D
authors.initials: BD
authors.lastname: Astill
authors.affiliation: Department of Physiology, Arizona College of Osteopathic Medicine, Midwestern University, Glendale, Arizona.
authors.forename: Mark S
authors.initials: MS
authors.lastname: Katsma
authors.affiliation: Department of Physiology, Arizona College of Osteopathic Medicine, Midwestern University, Glendale, Arizona.
authors.forename: David J
authors.initials: DJ
authors.lastname: Cauthon
authors.affiliation: Department of Physiology, Arizona College of Osteopathic Medicine, Midwestern University, Glendale, Arizona.
authors.forename: Jason
authors.initials: J
authors.lastname: Greenlee
authors.affiliation: Department of Physiology, Arizona College of Osteopathic Medicine, Midwestern University, Glendale, Arizona.
authors.forename: Mark
authors.initials: M
authors.lastname: Murphy
authors.affiliation: Arizona School of Podiatric Medicine, Midwestern University, Glendale, Arizona; and.
authors.forename: Donald
authors.initials: D
authors.lastname: Curtis
authors.affiliation: Department of Physiology, Arizona College of Osteopathic Medicine, Midwestern University, Glendale, Arizona; carrol71@purdue.edu.|Department of Health and Kinesiology, Purdue University, West Lafayette, Indiana.
authors.forename: Chad C
authors.initials: CC
authors.lastname: Carroll
mesh_terms: D000125:Achilles Tendon / Q000378:metabolism*; D000328:Adult; D003094:Collagen / Q000378:metabolism; D015444:Exercise / Q000502:physiology*; D005109:Extracellular Matrix / Q000378:metabolism; D005260:Female; D006801:Humans; D007334:Insulin-Like Growth Factor I / Q000378:metabolism*; D015850:Interleukin-6 / Q000378:metabolism; D008297:Male; D020782:Matrix Metalloproteinases / Q000378:metabolism*; D055070:Resistance Training / Q000379:methods; D012727:Sex Characteristics; D019715:Tissue Inhibitor of Metalloproteinase-1 / Q000378:metabolism
chemical_list: D015850:Interleukin-6; D019715:Tissue Inhibitor of Metalloproteinase-1; D007334:Insulin-Like Growth Factor I; D003094:Collagen; D020782:Matrix Metalloproteinases
keywords: IGF-1; IL-6; MMP; TIMP; exercise; tendon