Type III collagen in the intervertebral disc.

Several collagen types have now been isolated from the intervertebral disc, although type III collagen has previously only been extracted from human pathological disc. In this study, type III collagen has been isolated from normal human and bovine intervertebral disc and immunolocalized in sections of rat, sheep, bovine and 'normal' human intervertebral disc of various ages. Staining with antisera to type III collagen is localized primarily around the cells. Results indicate that cells of the disc sit in 'chondrons', similar to those seen in the deep and mid zones of articular cartilage. We suggest that type III collagen is present in the intervertebral disc and hypothesize that it may be involved in the organization of the pericellular environment, perhaps linking the chondron capsule to the interterritorial matrix.