Discogenic pain is associated with ingrowth of blood vessels and nerves, but uncertainty over the extent of ingrowth is hindering development of appropriate treatments. We hypothesise that adult human annulus fibrosus is such a dense crosslinked tissue that ingrowth Disc tissue was examined from 61 patients (aged 37–75 yrs) undergoing surgery for disc herniation, degeneration or scoliosis. 5 µm sections were stained with H&E to identify structures and tissue types. 30 µm frozen sections were examined using confocal microscopy, following immunostaining for CD31 (an endothelial cell marker), PGP 9.5 and Substance P (general and nociceptive nerve markers, respectively). Fluorescent tags were attached to the antibodies. ‘Volocity’ software was used to calculate numbers and total cross-sectional area of labelled structures, and to measure their distance from the nearest free surface (disc periphery, or annulus fissure).Introduction
Methods
Herniated disc tissue removed at surgery usually appears degenerated, and MRI often reveals degenerative changes in adjacent discs and vertebrae. This has fostered the belief that a disc Surgically-removed discs were examined using histology, immunohistochemistry and confocal microscopy. 21 samples of herniated tissues were compared with age-matched tissues excised from 11 patients whose discs had reached a similar Pfirrman grade of degeneration but without herniating. Degenerative changes were assessed separately in three tissue types (where present): nucleus, inner annulus, and outer annulus. Mann-Whitney U tests were used to compare ‘herniated’ vs ‘in-situ’ tissues.Introduction
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