IMMUNOHISTOCHEMICAL DEMONSTRATION OF SENSORY AND AUTONOMIC NERVE-TERMINALS IN HERNIATED LUMBAR DISC TISSUE

Study Design. Thirty-five lumbar disc herniations removed at surgery w ere studied by indirect immunocytochemistry. Objectives. To localize i mmunohistochemically both sensory and autonomic nerve terminals in dis c herniations. Summary of Background Data. Using various more or less specific histologic and histochemical methods, investigators have repo rted the presence of free nerve terminals in disc tissue. However, ver y few studies have, to date, convincingly demonstrated nerve terminals in disc tissue that morphologically resemble the tiny nerve terminals of sensory and autonomic nerve fibers. Methods. Amplification of the peroxidase reaction product in avidin-biotin-peroxidase complex immuno staining by the glucose oxidase-diaminobenzidine-nickel sulfate method was used to visualize small punctate nerve terminals at high magnific ation. Thin frozen sections from disc herniation tissue prefixed in Za mboni fixative were incubated with antibodies to synaptophysin to visu alize nerve terminals in general, and with antibodies to substance P a nd C-flanking peptide of neuropeptide Y to further characterize nerve terminals as either sensory or sympathetic. Results. Nerve terminals c ould be demonstrated in 29 (83%) of the 35 disc herniations. They were observed with the synaptophysin antibody in 17 of 35 (49%) disc herni ations, with substnace P in 16 of 35 (46%) disc herniations, and with C-flanking peptide of neuropeptide Y in 13 of 35 (37%) disc herniation s. Morphologically, the nerve terminals were seen as tiny immunoreacti ve dots. Some of the nerve terminals were observed close to disc cells , possibly suggesting direct interaction. Conclusions. Small nerve ter minals in disc herniations, both sensory substance P endings and sympa thetic C-flanking peptide of neuropeptide Y endings, could be involved in mechanisms of discogenic pain, disc tissue neurogenic inflammation , tissue repair processes after injury, and control of local blood cir culation in the newly formed blood vessels. Disc cells may be directly affected by the neuropeptides released from nearby nerve terminals.