Ageing of equine articular cartilage: structure and composition of aggrecan and decorin.
Abstract: In order to identify the pathological processes involved in the destruction of articular cartilage in arthritic diseases, it is first necessary to characterise the normal homeostasis of cartilage in a healthy joint. In particular, normal age-related changes in the biochemistry of cartilage complicate any comparisons that are made between diseased and healthy tissue. There are, however, no reports in the literature detailing the influence of ageing on the biochemistry of proteoglycans in equine articular cartilage. This study addresses the absence of such information by investigating the structure of aggrecan and decorin extracted from a wide age-range of full thickness equine tissue. The total glycosaminoglycan content of articular cartilage from the metacarpophalangeal joint remained relatively constant throughout life. In contrast, specific components such as hyaluronan increased in concentration with advancing age as did the content of a structural epitope present on keratan sulphate chains. There were also significant age-related changes in the sulphation pattern of chondroitin sulphate chains. The structure of the large aggregating proteoglycan (aggrecan) became more heterogeneous in size with increasing age and each of the subspecies of aggrecan identified in the extracts was shown to carry a hyaluronan binding region (G1) domain. All subspecies of aggrecan also expressed specific epitopes to keratan sulphate, chondroitin-4-sulphate and chondroitin-6-sulphate glycosaminoglycan chains. The structure of the small nonaggregating proteoglycan decorin and the aggrecan stabilising molecule link protein were demonstrated to be similar in size and charge to that reported for other species.
Publication Date: 1998-02-12 PubMed ID: 9458398DOI: 10.1111/j.2042-3306.1998.tb04087.xGoogle Scholar: Lookup
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- Journal Article
- Research Support
- Non-U.S. Gov't
Summary
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The study examines how the ageing process affects the biochemistry of proteoglycans in horse’s joint cartilage. It specifically looks at changes in the structure of aggrecan and decorin, two key components of cartilage.
Understanding the Biochemistry of Cartilage
- The first step to understanding the pathology of arthritic diseases requires a characterization of normal cartilage homeostasis in a healthy joint. The chemistry of cartilage changes naturally with age, complicating comparisons between healthy and diseased tissues.
- No previous research has investigated the impact of aging on proteoglycan biochemistry in equine articular cartilage. Proteoglycans are proteins that heavily glycosylated, forming an essential part of the cartilage’s extracellular matrix.
Investigating Aggrecan and Decorin
- This research tackled the issue by studying the structure of aggrecan and decorin extracted from equine tissue across a wide age range. Aggrecan and decorin are two important proteoglycans in cartilage, which contribute to its strength and resilience.
- The study found that the total glycosaminoglycan content in the cartilage of the metacarpophalangeal joint remained relatively constant throughout the horse’s lifespan.
Changes in Components
- Despite a steady total glycosaminoglycan content, some specific components, like hyaluronan, rose in concentration with advancing age. Hyaluronan is a glycosaminoglycan that plays a major role in the structural integrity of the joint.
- Additionally, a structural component found on keratan sulphate chains also increased with age. Significant age-related changes were observed in the sulphation pattern of the chondroitin sulphate chains. Chondroitin sulfate is another essential glycosaminoglycan that contributes to cartilage’s compressive strength.
Changes in Aggrecan
- The study discovered that aggrecan’s structure became more variable in size with age. All identified aggrecan subspecies had a hyaluronan binding region (G1) domain, and each expressed specific epitopes to keratan sulphate, chondroitin-4-sulphate, and chondroitin-6-sulphate glycosaminoglycan chains. Epitopes are parts of a molecule that the immune system recognizes.
Comparison with Other Species
- The structural form of the small nonaggregating proteoglycan, decorin, and the aggrecan stabilizing molecule, link protein, compared well in size and charge to what’s been reported for other species.
Cite This Article
APA
Platt D, Bird JL, Bayliss MT.
(1998).
Ageing of equine articular cartilage: structure and composition of aggrecan and decorin.
Equine Vet J, 30(1), 43-52.
https://doi.org/10.1111/j.2042-3306.1998.tb04087.x Publication
Researcher Affiliations
- Royal Veterinary College, University of London, London, UK.
MeSH Terms
- Aggrecans
- Aging / metabolism
- Animals
- Cartilage, Articular / chemistry
- Cartilage, Articular / metabolism
- Chondroitin Sulfate Proteoglycans / analysis
- Chondroitin Sulfate Proteoglycans / metabolism
- Chondroitin Sulfates / analysis
- Chondroitin Sulfates / metabolism
- Chromatography, Ion Exchange / methods
- Chromatography, Ion Exchange / veterinary
- DNA / analysis
- DNA / metabolism
- Decorin
- Electrophoresis, Polyacrylamide Gel / methods
- Electrophoresis, Polyacrylamide Gel / veterinary
- Extracellular Matrix Proteins
- Female
- Horses / metabolism
- Hyaluronic Acid / analysis
- Hyaluronic Acid / metabolism
- Immunoblotting / methods
- Immunoblotting / veterinary
- Lectins, C-Type
- Male
- Proteoglycans / analysis
- Proteoglycans / metabolism
Citations
This article has been cited 7 times.- Pritchard A, Nielsen BD, Robison C, Manfredi JM. Low dietary silicon supplementation may not affect bone and cartilage in mature, sedentary horses. J Anim Sci 2020 Dec 1;98(12).
- Brown WE, DuRaine GD, Hu JC, Athanasiou KA. Structure-function relationships of fetal ovine articular cartilage. Acta Biomater 2019 Mar 15;87:235-244.
- Vynios DH. Metabolism of cartilage proteoglycans in health and disease. Biomed Res Int 2014;2014:452315.
- Padalkar MV, Spencer RG, Pleshko N. Near infrared spectroscopic evaluation of water in hyaline cartilage. Ann Biomed Eng 2013 Nov;41(11):2426-36.
- Ofek G, Revell CM, Hu JC, Allison DD, Grande-Allen KJ, Athanasiou KA. Matrix development in self-assembly of articular cartilage. PLoS One 2008 Jul 30;3(7):e2795.
- Bathe M, Rutledge GC, Grodzinsky AJ, Tidor B. Osmotic pressure of aqueous chondroitin sulfate solution: a molecular modeling investigation. Biophys J 2005 Oct;89(4):2357-71.
- Bathe M, Rutledge GC, Grodzinsky AJ, Tidor B. A coarse-grained molecular model for glycosaminoglycans: application to chondroitin, chondroitin sulfate, and hyaluronic acid. Biophys J 2005 Jun;88(6):3870-87.
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