Human intervertebral disc acid glycosaminoglycans

Alcian blue critical electrolyte concentration (CEC) staining of intervertebral discs (annulus and nucleus of cervical, thoracic and lumbar discs) distinguished 3 groups where CEC staining correlated with age (less than 3 months; from 3 months to 5 years; over 10 years). The CEC increased markedly (implying increased sulphation of the glycosaminoglycans) in the period of maturation (fetal life to 10 years) and then remained constant throughout adult life. This is at variance with accepted views which attribute such changes to degenerative changes in old age. The major part of the CEC increase occurred after the disappearance of blood vessels from the disc, which is almost complete by 4 years. Our results are compatible with the hypothesis that keratan sulphate replaces chondroitin sulphate, functionally, in conditions of oxygen lack.