Loading-induced changes in synovial fluid affect cartilage metabolism.
Abstract: The object of this study was to determine whether changes in the synovial fluid (SF) induced by in vivo loading can alter the metabolic activity of chondrocytes in vitro, and, if so, whether insulin-like growth factor-I (IGF-I) is responsible for this effect. Therefore, SF was collected from ponies after a period of box rest and after they had been exercised for a week. Normal, unloaded articular cartilage explants were cultured in 20% solutions of these SFs for 4 days and chondrocyte bioactivity was determined by glycosaminoglycan (GAG) turnover (i.e., the incorporation of 35SO4 into GAG and the release of GAG into the medium). Furthermore, the extent to which the bioactivity is IGF-I-dependent was determined in a cartilage explant culture in 20% SF, in the presence and absence of anti-IGF-I antibodies. 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 IGF-I and IGFBP-3 levels were increased in post-exercise SF. There was a positive correlation between IGF-I levels and proteoglycan synthesis, but no correlation between IGF-I levels and proteoglycan release. Addition of anti-IGF-I antibodies significantly inhibited stimulation of proteoglycan synthesis in explants cultured in SF with 40%. However, there was no difference in inhibition of proteoglycan synthesis between pre- and post-exercise SF which indicated that the relative contribution of IGF-I in the stimulating effect of SF did not change. Proteoglycan release was not influenced by the presence of anti-IGF-I antibodies. It is concluded that chondrocyte metabolic activity is at least partially regulated by changes in the SF induced by in vivo loading. Exercise altered the SF in a way that it had a favourable effect on cartilage PG content by enhancing the PG synthesis and reducing the PG breakdown. IGF-I is an important contributor to the overall stimulating effect of SF on cartilage metabolism. It is, however, unlikely that IGF-I is the only mediator in the exercise-induced increase in this stimulating effect.
Publication Date: 2000-07-27 PubMed ID: 10912177
The Equine Research Bank provides access to a large database of publicly available scientific literature. Inclusion in the Research Bank does not imply endorsement of study methods or findings by Mad Barn.
- Journal Article
Summary
This research summary has been generated with artificial intelligence and may contain errors and omissions. Refer to the original study to confirm details provided. Submit correction.
The study investigates how physical activity impacts the properties of synovial fluid and its effects on chondrocyte metabolism, also evaluating if insulin-like growth factor-I (IGF-I) has a role in this process.
Research Objectives and Methodology
- The research aimed to explore whether changes in synovial fluid due to in vivo loading (physical activity) can modify the metabolic activity of chondrocytes, and whether IGF-I contributes to this effect.
- Synovial fluid was gathered from ponies after a period of rest and then after a week of physical activity.
- Chondrocyte bioactivity was examined over 4 days by culturing normal, unloaded articular cartilage explants in 20% solutions of the collected synovial fluids.
- They measured glycosaminoglycan (GAG) turnover as a marker of chondrocyte activity, evaluating the incorporation of 35SO4 into GAG and the release of GAG into the medium.
- The role of IGF-I in this activity was determined by comparing the results in the presence and absence of anti-IGF-I antibodies.
Key Findings
- Cartilage cultured in post-exercise synovial fluid showed enhanced GAG synthesis and reduced GAG release compared to pre-exercise fluid.
- IGF-I and IGFBP-3 levels were increased in post-exercise synovial fluid.
- IGF-I levels positively correlated with proteoglycan synthesis, but there was no correlation with proteoglycan release.
- Addition of anti-IGF-I antibodies inhibited proteoglycan synthesis, however, the extent of inhibition was similar for both pre- and post-exercise synovial fluid, suggesting the relative influence of IGF-I remains static.
- The presence of anti-IGF-I antibodies did not affect proteoglycan release.
Conclusions
- The results indicate that changes in synovial fluid due to physical activity partially regulate chondrocyte metabolism.
- Physical activity altered the synovial fluid in a way that enhanced proteoglycan synthesis and reduced proteoglycan breakdown, thus favourably affecting cartilage proteoglycan content.
- IGF-I plays a significant role in the stimulating effect of synovial fluid on cartilage metabolism, but likely isn’t the only factor involved in the exercise-induced increase in this stimulating effect.
Cite This Article
APA
van de Lest CH, van den Hoogen BM, van Weeren PR.
(2000).
Loading-induced changes in synovial fluid affect cartilage metabolism.
Biorheology, 37(1-2), 45-55.
Publication
Researcher Affiliations
- Faculty of Veterinary Sciences, Department of Biochemistry, Utrecht University, The Netherlands.
MeSH Terms
- Animals
- Antibodies, Monoclonal / pharmacology
- Blotting, Western
- Cartilage, Articular / metabolism
- Chondrocytes / metabolism
- Culture Techniques / methods
- Glycosaminoglycans / metabolism
- Horses
- Insulin-Like Growth Factor Binding Protein 3 / analysis
- Insulin-Like Growth Factor Binding Protein 3 / metabolism
- Insulin-Like Growth Factor I / analysis
- Insulin-Like Growth Factor I / immunology
- Male
- Proteoglycans / metabolism
- Statistics, Nonparametric
- Stress, Mechanical
- Synovial Fluid / physiology
Citations
This article has been cited 5 times.- Carballo CB, Coelho TRP, de Holanda Afonso RC, Faria JCO, Alves T, Monte SM, Ventura Matioszek GM, Moura-Neto V, Brito JM. Osteoarthritic Synovial Fluid and TGF-β1 Induce Interleukin-18 in Articular Chondrocytes.. Cartilage 2020 Jul;11(3):385-394.
- MacNicol JL, Lindinger MI, Pearson W. A time-course evaluation of inflammatory and oxidative markers following high-intensity exercise in horses: a pilot study.. J Appl Physiol (1985) 2018 Apr 1;124(4):860-865.
- Howard JS, Mattacola CG, Romine SE, Lattermann C. Continuous Passive Motion, Early Weight Bearing, and Active Motion following Knee Articular Cartilage Repair: Evidence for Clinical Practice.. Cartilage 2010 Oct;1(4):276-86.
- Brand JA, McAlindon TE, Zeng L. A 3D system for culturing human articular chondrocytes in synovial fluid.. J Vis Exp 2012 Jan 31;(59):e3587.
- Luan Y, Kong L, Howell DR, Ilalov K, Fajardo M, Bai XH, Di Cesare PE, Goldring MB, Abramson SB, Liu CJ. Inhibition of ADAMTS-7 and ADAMTS-12 degradation of cartilage oligomeric matrix protein by alpha-2-macroglobulin.. Osteoarthritis Cartilage 2008 Nov;16(11):1413-20.
Use Nutrition Calculator
Check if your horse's diet meets their nutrition requirements with our easy-to-use tool Check your horse's diet with our easy-to-use tool
Talk to a Nutritionist
Discuss your horse's feeding plan with our experts over a free phone consultation Discuss your horse's diet over a phone consultation
Submit Diet Evaluation
Get a customized feeding plan for your horse formulated by our equine nutritionists Get a custom feeding plan formulated by our nutritionists
