Mechanical behavior of articular cartilage quantitative changes with enzymatic alteration of the proteoglycan...

The in-vitro viscoelastic mechanical response of normal rabbit articular cartilage is strongly dependent on the quantity and integrity of the proteoglycan fraction of the tissue matrix. Experimental results demonstrate that specific functional relationships exist between shear moduli, retardation time spectra, and proteoglycan content. Quantitative enzymolysis of the proteoglycan fraction of the tissue alters the form of these relationships in a fashion consistent with the altered physiochemical make-up of the tissue. The observed changes in mechanical behavior with controlled enzymolysis are similar to those associated with the early stages of osteoarthritis, rheumatoid arthritis, joint sepsis, and synovitis in animal models.