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Meniscal tissue explants response depends on level of dynamic compressive strain
B Zielinska1, M Killian, M Kadmiel
1Biotechnology Research Center, Department of Mechanical Engineering-Engineering Mechanics, Michigan Technological University, Houghton, MI 49931, United States.
Osteoarthritis and Cartilage
|January 6, 2009
Summary
Altered knee meniscus loading after surgery increases catabolic activity. Dynamic strains of 10-20% upregulate genes like MMPs and ADAMTS4, indicating heightened tissue breakdown and potential osteoarthritis development.
Area of Science:
- Biomechanical Engineering
- Orthopedic Research
- Molecular Biology
Background:
- Partial meniscectomy alters knee joint biomechanics.
- In vitro studies show dynamic compression increases glycosaminoglycan release and IL-1alpha expression in meniscal tissue.
Purpose of the Study:
- To investigate if mechanical loading induces endogenous IL-1 expression.
- To determine downstream gene expression changes in anabolic and catabolic molecules, including MMPs, in response to compressive loading.
Main Methods:
- Porcine meniscal explants were subjected to dynamic compression (0%, 10%, 20%) at 1Hz for 2 hours.
- Gene expression of MMPs, ADAMTS4, ADAMTS5, TNFalpha, TGFbeta, COX-2, COL-1, and aggrecan was measured.
- Prostaglandin E(2) release was quantified in response to varying dynamic compression levels.
Main Results:
- 20% dynamic strain upregulated MMP-1, MMP-3, MMP-13, and ADAMTS4 expression compared to controls.
- 10% strain upregulated aggrecan, COX-2, and ADAMTS5 gene expression.
- COL-1, TIMP-1, and TGFbeta gene expression levels were independent of the applied strain magnitude.
Conclusions:
- Mechanical loading of the meniscus, ranging from 10% to 20% dynamic strain, can elevate its catabolic activity.
- These findings suggest a mechanism by which altered loading post-meniscectomy may contribute to meniscus degeneration.
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