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Updated: Aug 10, 2026
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A Friction Testing-Bioreactor Device for Study of Synovial Joint Biomechanics, Mechanobiology, and Physical Regulation
Published on: June 2, 2022
Hyaluronan secretion by synoviocytes is mechanosensitive
T S Momberger1, J R Levick, R M Mason
1Division of Biomedical Sciences, Faculty of Medicine, Imperial College London, SW7 2AZ, United Kingdom.
Summary
Joint use stimulates hyaluronan (HA) production in synoviocytes. Mechanical stretch, even brief, enhances HA secretion, requiring new protein synthesis and gene transcription for this key joint component.
Area of Science:
- Biochemistry
- Cell Biology
- Rheumatology
Background:
- Hyaluronan (HA) is crucial for synovial fluid and joint lubrication.
- The relationship between joint usage and HA production remains unclear.
- Previous studies suggested joint distension increases HA, but direct cellular evidence was lacking.
Purpose of the Study:
- To investigate whether synoviocytes exhibit mechanosensitive hyaluronan secretion in vitro.
- To determine the role of mechanical stretch duration on HA secretion.
- To explore the molecular mechanisms regulating stretch-induced HA production.
Main Methods:
- Primary rabbit synoviocyte cultures were subjected to static mechanical stretch using a Flexcell apparatus.
- HA secretion was measured in the culture medium over time.
- Gene expression (HAS2) and protein synthesis inhibition (Actinomycin D, cycloheximide) were assessed.
Main Results:
- Mechanical stretch significantly increased HA secretion by 57% over 3 hours.
- Both sustained and short-duration (10 min) stretch effectively stimulated HA secretion.
- Inhibition of transcription and protein synthesis blocked stretch-induced HA secretion.
- HAS2 mRNA levels showed only minor increases with stretch, but significantly with TGF-beta1 and IL-1beta.
Conclusions:
- Synoviocytes possess a mechanosensitive pathway for regulating HA secretion.
- This pathway relies on gene transcription and de novo protein synthesis.
- Mechanical loading of joints likely influences HA levels through synoviocyte stimulation.
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