Title
Topographical mapping of biochemical properties of articular cartilage in the equine fetlock joint
Author
Brama, P.A.J.
Tekoppele, J.M.
Bank, R.A.
Karssenberg, D.
Barneveld, A.
van Weeren, P.R.
Publication year
2000
Abstract
The aim of this study was to evaluate topographical differences in the biochemical composition of the extracellular matrix of articular cartilage of the normal equine fetlock joint. Water content, DNA content, glycosaminoglycan (GAG) content and a number of characteristics of the collagen network (total collagen content, levels of hydroxylysine- (Hyl) and the crosslink hydroxylysylpyridinoline, (HP) of articular cartilage in the proximal 1st phalanx (P1), distal 3rd metacarpal bone (MC), and proximal sesamoid bones (PSB) were determined in the left and right fetlock joint of 6 mature horses (age 5-9 years). Twenty-eight sites were sampled per joint, which included the clinically important areas often associated with pathology. Biochemical differences were evaluated between sampling sites and related with the predisposition for osteochondral injury and type of loading. Significant regional differences in the composition of the extracellular matrix existed within the joint. Furthermore, left and right joints exhibited biochemical differences. Typical topographic distribution patterns were observed for each parameter. In P1 the dorsal and palmar articular margin showed a significantly lower GAG content than the more centrally located sites. Collagen content and HP crosslinks were higher at the joint margins than in the central area. Also, in the MC, GAG content was significantly lower at the (dorsal) articular margin compared with the central area. Consistent with findings in P1, collagen and HP crosslinks were significantly lower in the central area compared to the (dorsal) articular margin. Biochemical and biomechanical heterogeneity of articular cartilage is supposed to reflect the different functional demands made at different sites. In the present study, GAG content was highest in the constantly loaded central areas of the joint surfaces. In contrast, collagen content and HP crosslinks were higher in areas intermittently subjected to peak loading which suggests that the response to a certain type of loading of the various components of the extracellular matrix of articular cartilage are different. The differences in biochemical characteristics between the various sites may help to explain the site specificity of osteochondral lesions commonly found in the equine fetlock joint. Finally, these findings emphasise that the choice of sampling sites may profoundly influence the outcome of biochemical studies of articular cartilage.
Subject
Biology
Biomedical Research
Biochemical
Cartilage
Horse
Mapping
Site
1,9 dimethylmethylene blue
1,9-dimethylmethylene blue
amino acid
bisbenzimide
collagen
DNA
drug derivative
fluorescent dye
glycosaminoglycan
hydroxylysine
methylene blue
pyridinoline
water
animal
animal disease
article
articular cartilage
biomechanics
biopsy
chemistry
extracellular matrix
forelimb
high performance liquid chromatography
histology
horse
joint
physiology
Amino Acids
Animals
Biomechanics
Biopsy
Bisbenzimide
Cartilage, Articular
Chromatography, High Pressure Liquid
Collagen
DNA
Extracellular Matrix
Fluorescent Dyes
Forelimb
Glycosaminoglycans
Horses
Hydroxylysine
Joints
Methylene Blue
Water
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http://resolver.tudelft.nl/uuid:d37f5536-38de-4596-93f3-30454afda7ea
TNO identifier
235420
ISSN
0425-1644
Source
Equine Veterinary Journal, 32 (1), 19-26
Document type
article