title: Serum osteocalcin and CTX-MMP concentration in young exercising thoroughbred racehorses.
abstract: Bone responds to exercise with changes in bone (re-)modelling, which might be monitored non-invasively with biochemical bone markers. The aim of this study was to evaluate the influence of exercise on serum osteocalcin and serum carboxy-terminal cross-linked telopeptide of type I collagen generated by matrix metalloproteinases (CTX-MMP) concentration in young racehorses. Seventy-one 2 to 4-year-old Thoroughbreds were included in this prospective infield study. Blood sampling was performed six times (i.e. six sampling cycles) during a 9-month period. Serum samples were analysed with commercial osteocalcin and CTX-MMP radioimmunoassays. Two-year-old racehorses had higher serum osteocalcin and CTX-MMP values than 3-year-old horses. Gender and training amplitude did not significantly influence serum osteocalcin and CTX-MMP values. Two-year-old horses showed an increase in osteocalcin values between cycles 2 and 3 and an increase in serum CTX-MMP values between cycles 1 and 2. Serum osteocalcin and CTX-MMP concentrations decreased between cycles 4 and 5, and 5 and 6. Three-year-old horses showed an increase in serum osteocalcin levels between cycles 3 and 4 and an increase in serum CTX-MMP concentrations between cycles 1 and 2, and 3 and 4. Serum osteocalcin levels decreased between cycles 5 and 6, whereas serum CTX-MMP levels decreased between cycles 4 and 5, and 5 and 6. Two- and three-year-old horses showed a decreased osteocalcin/CTX-MMP ratio between cycles 1 and 2. Moreover, 2-year-old horses showed an increase in the osteocalcin/CTX-MMP ratio between cycles 2 and 3. Sore shin formation did not significantly influence serum osteocalcin and CTX-MMP values. Serum osteocalcin and CTX-MMP are promising bone markers for monitoring exercise induced changes in equine bone metabolism.
authors.affiliation: Department of Large Animal Internal Medicine, Faculty of Veterinary Medicine, University of Liège, Belgium. bcarstanjen@vet-alfort.fr
authors.forename: B
authors.initials: B
authors.lastname: Carstanjen
authors.forename: H
authors.initials: H
authors.lastname: Amory
authors.forename: J
authors.initials: J
authors.lastname: Sulon
authors.forename: O
authors.initials: O
authors.lastname: Hars
authors.forename: B
authors.initials: B
authors.lastname: Remy
authors.forename: P
authors.initials: P
authors.lastname: Langlois
authors.forename: O M
authors.initials: OM
authors.lastname: Lepage
mesh_terms: D000367:Age Factors; D000818:Animals; D001842:Bone and Bones / Q000378:metabolism*; D003094:Collagen / Q000097:blood*; D024042:Collagen Type I; D005260:Female; D006736:Horses / Q000097:blood* / Q000378:metabolism; D008297:Male; D020782:Matrix Metalloproteinases / Q000378:metabolism*; D015675:Osteocalcin / Q000097:blood*; D010455:Peptides / Q000097:blood*; D010805:Physical Conditioning, Animal / Q000502:physiology*; D011446:Prospective Studies; D011863:Radioimmunoassay / Q000662:veterinary
chemical_list: D024042:Collagen Type I; D010455:Peptides; C052929:collagen type I trimeric cross-linked peptide; D015675:Osteocalcin; D003094:Collagen; D020782:Matrix Metalloproteinases