Degeneration affects the structure-function relationship of the human meniscus.

Area of Science:

• Biomedical Engineering
• Orthopedics
• Rheumatology

Background:

• Osteoarthritis (OA) involves degeneration of joint tissues, including the meniscus.
• The relationship between meniscal structural integrity, function, and inflammatory mediators in OA is not fully understood.

Purpose of the Study:

• To investigate the association between altered structure-function relationships in osteoarthritic menisci and the production of catabolic and inflammatory mediators.
• To examine the role of the terminal complement complex (C5b-9) in meniscal degeneration.

Main Methods:

• Human knee joint menisci (n=24) were categorized into mild and severe degeneration groups.
• Mechanical testing (pull-to-failure, stress-relaxation) and biochemical assays (DNA, sGAG, collagen) were performed.
• Immunohistochemistry assessed collagen types I/II, aggrecan, MMP-3, IL-6, C5b-9, and VEGF; Spearman correlations were calculated.

Main Results:

• Severely degenerated menisci exhibited lower elastic modulus and tensile strength compared to mildly degenerated ones.
• Degeneration increased permeability and sGAG content while decreasing overall collagen.
• Severely degenerated menisci showed increased production of MMP-3, IL-6, and C5b-9.

Conclusions:

• Distinct meniscal phenotypes are associated with OA degeneration severity.
• Correlations between collagen and mechanical properties shifted from positive to negative as degeneration progressed, indicating complex changes in meniscal tissue during OA.