Abstract
Mature human intervertebral disc cells have generally been described as being either fibroblast-like or chondrocyte-like; i.e. appearing either elongated and bipolar or rounded/oval. Fibroblast-like cells are observed within the outer regions of the anulus fibrosus whilst chondrocyte-like cells are found in the more central regions of the disc. However, a few reports have noted that in some circumstances disc cells appear to extend more elaborate cytoplasmic processes into their surrounding extracellular matrix. In this study, we have examined healthy and pathological human intervertebral discs for the presence of the cytoskeletal elements, F-actin and vimentin.
Tissues examined included discs of no known pathology, discs with spondylolithesis, scoliosis specimens taken from the convex and concave sides, and degenerated discs. F-actin was not readily observed within discs cells but was a marked feature of vascular tissue within the disc and occasionally seen in infiltrating cells. Vimentin was more readily seen within cells of the inner anulus fibrosus and nucleus pulposus. In general, disc cell morphology was fibrocyte or chondrocyte-like; however, in spondylolisthetic discs, cells with numerous cytoplasmic projections were frequently observed.
The differential morphologies and cytoskeletal composition observed in disc cells may be indicative of variations in mechanical strains and/or pathologies, or indeed of cell function.
The abstracts were prepared by Dr C Pither. Correspondence should be addressed to him at the British Orthopaedic Association, Royal College of Surgeons, 35–43 Lincoln’s Inn Fields, London WC2A 3PN
