Biochemical and immunological study of lumbar disc degeneration.

Proteoglycans of 18 lumbar discs obtained at surgery for lumbar disc lesion were studied biochemically and immunologically (using monoclonal antibody that recognizes core protein of annulus fibrosus proteoglycans) and compared with the results of similar studies on discs obtained at autopsy and Zielke's operation for scoliosis. Disc proteoglycans showed a decrease in extraction and hexuronic acid/protein weight ratio with age in both surgical and post-mortem specimens. Although the molecular weight of proteoglycan monomer seemed to show a slight decrease, that of chondroitin sulfate chain showed no change with age in surgical discs. The proportion of proteoglycan aggregate showed a decrease with age until 40 years old, it went up thereafter because of the loss of proteoglycan monomers. This biochemical degeneration paralleled discogramic degeneration and monoclonal antibody that recognized core protein showed a strong affinity with severely degenerated discs. Besides aging, lumbar instability seemed to exert a profound influence on the progression of degeneration.