Meniscal tissue explants response depends on level of dynamic compressive strain.
OBJECTIVE
Following partial meniscectomy, the remaining meniscus is exposed to an altered loading environment. In vitro 20% dynamic compressive strains on meniscal tissue explants has been shown to lead to an increase in release of glycosaminoglycans from the tissue and increased expression of interleukin-1alpha (IL-1alpha). The goal of this study was to determine if compressive loading which induces endogenously expressed IL-1 results in downstream changes in gene expression of anabolic and catabolic molecules in meniscal tissue, such as MMP expression.


METHODS
Relative changes in gene expression of MMP-1, MMP-3, MMP-9, MMP-13, A Disintegrin and Metalloproteinase with ThromboSpondin 4 (ADAMTS4), ADAMTS5, TNFalpha, TGFbeta, COX-2, Type I collagen (COL-1) and aggrecan and subsequent changes in the concentration of prostaglandin E(2) released by meniscal tissue in response to varying levels of dynamic compression (0%, 10%, and 20%) were measured. Porcine meniscal explants were dynamically compressed for 2h at 1Hz.


RESULTS
20% dynamic compressive strains upregulated MMP-1, MMP-3, MMP-13 and ADAMTS4 compared to no dynamic loading. Aggrecan, COX-2, and ADAMTS5 gene expression were upregulated under 10% strain compared to no dynamic loading while COL-1, TIMP-1, and TGFbeta gene expression were not dependent on the magnitude of loading.


CONCLUSIONS
This data suggests that changes in mechanical loading of the knee joint meniscus from 10% to 20% dynamic strain can increase the catabolic activity of the meniscus.
Zielinska
B
B
Biotechnology Research Center, Department of Mechanical Engineering-Engineering Mechanics, Michigan Technological University, Houghton, MI 49931, United States.
Killian
M
M
Kadmiel
M
M
Nelsen
M
M
Haut Donahue
T L
TL
D000818:Animals; D017364:Collagenases / Q000235:genetics / Q000378:metabolism*; D019245:Compressive Strength; D015870:Gene Expression / Q000235:genetics; D007719:Knee Joint / Q000378:metabolism*; D008592:Menisci, Tibial / Q000473:pathology*; D020370:Osteoarthritis, Knee / Q000235:genetics / Q000473:pathology*; D013314:Stress, Mechanical; D013552:Swine; D000070600:Tibial Meniscus Injuries; D015854:Up-Regulation; D016474:Weight-Bearing
D017364:Collagenases