The large proteoglycans of the human intervertebral disc: Changes in their biosynthesis and structure with age5 topography5 and pathology

Study Design. The structure and extracellular assembly of the newly synthesized aggregating proteoglycans of the tin man intervertebral dish were examined using an expiate culture system. Objectives. The objective was to study the changes with aging, topography, and pathology, comparing newly synthesized with endogenous proteoglycans. Summary of Background Data. No detailed studies of the biosynthesis of human disc proteoglycans have been previously reported. Methods. A method of explants culture that minimizes swelling and matrix loss was used to maintain the tissue architecture. Slices of postmortem and pathologic disc tissues were incubated in medium containing polyethylene glycol at appropriate concentration a to 3a acne the swelling pressure of the tissues. The disc slices were contained in small-pore dialysis tubing to prevent penetration of the polyethylene glycol into the tissue. The newly synthesized proteoglycans were rsdiolabeled with [35S]-sulphate. Proteoglycans were then extracted from the tissue slices and characterized with gel chromatographic and electrophoresis techniques. Results. It was found that a simple, high molecular Weight proteoglycan is the major 35S-labceled synthesis product of disc cells at all ages. However, biosynthetic changes do occur: The monomer made by fetal and newborn disc sells was larger Than that of Huts, Furthermore, adult disc coils made their minor large 35S-labeled products, the synthesis pattern of which varied between regions. Conclusion. These results provide the first evidence than biosynthetic changes contribute to the age-related increase in theft heterogeneity of the humbly disc proteoglycan population.