Streaming potentials: a sensitive index of enzymatic degradation in articular cartilage.

Under physiological conditions, the extracellular matrix of articular cartilage contains a high fixed-charge density, associated with its ionized proteoglycan (PG) molecules. Compression of the highly charged cartilage matrix within the physiologic range leads to the production of electrical streaming potentials. We observed significant changes in the potential response due to chemical modifications of the matrix, such as extraction of PG and glycosaminoglycan (GAG) moieties using chondroitinase-ABC adn trypsin. The streaming potential was a sensitive index of the degradative loss of these matrix constituents and of the kinetics of the enzymatic degradative process.