Intervertebral Disc Cells Produce Interleukins Found in Patients with Back Pain.

OBJECTIVE: To examine the link between cytokines in intervertebral disc (IVD) tissues and axial back pain.

DESIGN: In vitro study with human IVD cells cultured from cadaveric donors and annulus fibrosus (AF) tissues from patients.

RESULTS: Cultured nucleus pulposus (NP) and AF cells were stimulated with interleukin (IL)-1β. IL-8 and IL-7 gene expression was analyzed using real-time polymerase chain reaction. IL-8 protein was quantified by enzyme-linked immunosorbent assay. After IL-1β stimulation, IL-8 gene expression increased 26,541 fold in NP cells and 22,429 fold in AF cells, whereas protein released by the NP and AF cells increased 2,389- and 1,784-fold, respectively. IL-7 gene expression increased 3.3-fold in NP cells (P < 0.05).Cytokine profiles in AF tissues collected from patients undergoing surgery for back pain (painful group) or scoliosis (controls) were compared by cytokine array. IL-8 protein in the AF tissues from patients with back pain was 1.81-fold of that in controls. IL-7 and IL-10 in AF tissues from the painful group were 6.87 and 4.63 times greater than the corresponding values in controls, respectively (P < 0.05).

CONCLUSION: Inflammatory mediators found in AF tissues from patients with discogenic back pain are likely produced by IVD cells and may play a key role in back pain.