Target tissue models: the proteoglycans and degeneration of the human intervertebral disc.

Seventy-five intervertebral discs from 15 spines were analyzed after morphologic grading. With degeneration, the water and proteoglycan (PG) contents decreased and the collagen content increased. The PG was isolated from 20 discs by single-stage dissociative density gradient ultracentrifugation. Neither the chondroitin 6-sulphate nor the protein contents of the PG changed with degeneration although the keratan sulphate fell slightly.