Loading-induced changes in synovial fluid affect cartilage metabolism.
The purpose of this study was to determine whether changes in the synovial fluid (SF) induced by in vivo loading can induce an alteration in the metabolic activity of chondrocytes in vitro. Therefore, SF was collected from ponies after a period of box rest and after they had exercise for a week. Normal, unloaded articular cartilage explants were cultured in 20% solutions of these SFs for 4 days and chondrocyte activity was determined by glycosaminoglycan (GAG) turnover. In explants cultured in post-exercise SF, GAG synthesis was enhanced and GAG release was diminished when compared to cultures in pre-exercise SF. SF analysis showed that levels of insulin-like growth factors (IGF-I and IGF-II) tended to be higher in post-exercise SF, while no differences were found in metalloproteinase activity, hyaluronic acid and protein concentrations. This study showed that anabolic effects of joint loading on cartilage are, at least partially, mediated by alterations in the SF.
Van den Hoogen
B M
BM
Department of General and Large Animal Surgery, Utrecht University, The Netherlands.
van de Lest
C H
CH
van Weeren
P R
PR
Lafeber
F P
FP
Lopes-Cardozo
M
M
van Golde
L M
LM
Barneveld
A
A
D000818:Animals; D002350:Carpus, Animal; D002358:Cartilage, Articular / Q000166:cytology / Q000378:metabolism*; D006736:Horses / Q000502:physiology*; D006820:Hyaluronic Acid / Q000378:metabolism; D007334:Insulin-Like Growth Factor I / Q000378:metabolism; D007335:Insulin-Like Growth Factor II / Q000378:metabolism; D008297:Male; D008666:Metalloendopeptidases / Q000378:metabolism; D009924:Organ Culture Techniques; D010805:Physical Conditioning, Animal; D011506:Proteins / Q000378:metabolism; D013582:Synovial Fluid / Q000378:metabolism*; D016474:Weight-Bearing / Q000502:physiology*
D011506:Proteins; D007334:Insulin-Like Growth Factor I; D007335:Insulin-Like Growth Factor II; D006820:Hyaluronic Acid; D008666:Metalloendopeptidases