Title
Functional adaptation of equine articular cartilage: The formation of regional biochemical characteristics up to age one year
Author
Brama, P.A.J.
Tekoppele, J.M.
Bank, R.A.
Barneveld, A.
van Weeren, P.R.
Gaubius Instituut TNO
Publication year
2000
Abstract
Biochemical heterogeneity of cartilage within a joint is well known in mature individuals. It has recently been reported that heterogeneity for proteoglycan content and chondrocyte metabolism in sheep develops postnatally under the influence of loading. No data exist on the collagen network in general or on the specific situation in the horse. The objective of this study was to investigate the alterations in equine articular cartilage biochemistry that occur from birth up to age one year, testing the hypothesis that the molecular composition of equine cartilage matrix is uniform at birth and biochemical heterogeneity is formed postnatally. Water content, DNA content, glycosaminoglycan content (GAG) and biochemical characteristics of the collagen network (collagen content, hydroxylysine content and hydroxylysylpyridinoline [HP] crosslinks) were measured in immature articular cartilage of neonatal (n = 16), 5-month-old foals (n = 16) and yearlings (n = 16) at 2 predefined differently loaded sites within the metacarpophalangeal joint. Statistical differences between sites were analysed by ANOVA (P<0.01), and age correlation was tested by Pearson's product moment correlation analysis (P<0.01). In neonatal cartilage no significant site differences were found for any of the measured biochemical parameters. This revealed that the horse has a biochemically uniform joint (i.e. the cartilage) at birth. In the 5-month-old foals and yearlings, significant site differences, comparable to those in the mature horse, were found for DNA, GAG, collagen content and hydroxylysine content. This indicates that functional adaptation of articular cartilage to weight bearing for these biochemical parameters takes place during the first months postpartum. Water content and HP crosslinks showed no difference between the 2 sites from neonatal horses, 5-month-old animals and yearlings. At both sites water, DNA and GAG decreased during maturation while collagen content, hydroxylysine content and HP crosslinks increased. We propose that a foal is born with a uniform biochemical composition of cartilage in which the functional adaptation to weight bearing takes place early in life. This adaptation results in biochemical and therefore biomechanical heterogeneity and is thought to be essential to resist the different loading conditions to which articular cartilage is subjected during later life. As collagen turnover is extremely low at mature age, an undisturbed functional adaptation of the collagen network of articular cartilage at a young age may be of significant importance for future strength and resistance to injury.
Subject
Health Biology
Biomedical Research
Functional adaptation
Horse
Site
1,9 dimethylmethylene blue
1,9-dimethylmethylene blue
Amino acid
Bisbenzimide
Drug derivative
Glycosaminoglycan
Hydroxylysine
Hydroxyproline
Methylene blue
Pyridinoline
Water
Age
Animal disease
Articular cartilage
Chemistry
High performance liquid chromatography
Horse
Joint
Newborn
Nonparametric test
Physiology
Age Factors
Amino Acids
Animals
Animals, Newborn
Bisbenzimide
Cartilage, Articular
Chromatography, High Pressure Liquid
Collagen
DNA
Glycosaminoglycans
Horses
Hydroxylysine
Hydroxyproline
Joints
Methylene Blue
Statistics, Nonparametric
Water
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TNO identifier
235544
ISSN
0425-1644
Source
Equine Veterinary Journal, 32 (3), 217-221
Document type
article