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Age‐related changes in serum insulin‐like growth factor‐I, insulin‐like growth factor‐I binding protein‐3 and articular cartilage structure in Thoroughbred horses
Author(s) -
FORTIER L. A.,
KORNATOWSKI M. A.,
MOHAMMED H. O.,
JORDAN M. T.,
O'CAIN L. C.,
STEVENS W. B.
Publication year - 2005
Publication title -
equine veterinary journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.82
H-Index - 87
eISSN - 2042-3306
pISSN - 0425-1644
DOI - 10.2746/0425164054406838
Subject(s) - medicine , endocrinology , ageing , insulin like growth factor , cartilage , growth factor , articular cartilage , horse , biology , pathology , anatomy , osteoarthritis , receptor , paleontology , alternative medicine
Summary Reasons for performing study : Structural changes in articular cartilage associated with the ageing process require definition for investigators performing developmental and age‐related studies, for which information is lacking. Objectives : To 1) determine the onset and end of puberty as defined by serum insulin like growth factor (IGF‐I) and IGF‐binding protein‐3 (IGFBP‐3) concentrations and 2) correlate articular‐epiphyseal cartilage complex structural changes with the onset and end of puberty. Methods : IGF‐1 and IGFBP‐3 were measured in serum samples from normal female and male horses age 9‐715 days to determine peak and steady‐state values for horses transitioning through puberty. Osteochondral tissue sections were obtained from horses age 120‐840 days (4‐28 months) and examined histologically for cartilage canals and tidemark formation. Results : In male and female horses, serum IGF‐1/IGFBP‐3 concentrations peaked at approximately 225 days, defining the onset of puberty. Cartilage canals were absent from articular cartilage just prior to this time point. IGF‐1/IGFBP‐3 concentrations declined to steady‐state levels at approximately age 450 days, signalling exit from puberty and therefore the beginning of ageing. This time point correlated to initial formation of a tidemark in the osteochondral tissue sections. Conclusions : Horses may be considered pubescent at age 225‐450 days, and post pubescent and ageing after age 450 days. Potential relevance : Defining the normal post natal to post pubescent concentrations for serum IGF‐I and serum IGFBP‐3 establishes subsets of animals for age‐related studies and may be used to monitor horses for abnormally high IGF‐1 concentrations due to natural disease or subsequent to systemic growth hormone administration.