Intervertebral Disc Cells Produce Interleukins Found in Patients with Back Pain

Area of Science:

• Biomedical Science
• Molecular Biology
• Immunology

Background:

• Axial back pain is a prevalent condition with complex etiologies.
• Intervertebral disc (IVD) degeneration is implicated in back pain, but the specific molecular mechanisms remain incompletely understood.
• Cytokines, signaling proteins involved in inflammation, are potential contributors to pain signaling within the IVD.

Purpose of the Study:

• To investigate the relationship between specific cytokines within human intervertebral disc (IVD) tissues and the presence of axial back pain.
• To determine if IVD cells cultured in vitro produce inflammatory cytokines in response to stimulation.
• To compare cytokine expression profiles in annulus fibrosus (AF) tissues from patients with and without back pain.

Main Methods:

• Human IVD cells (nucleus pulposus and annulus fibrosus) were cultured and stimulated with interleukin (IL)-1β.
• Gene expression of IL-8 and IL-7 was quantified using real-time polymerase chain reaction.
• Protein levels of IL-8 were measured by enzyme-linked immunosorbent assay.
• Cytokine profiles in AF tissues from back pain patients and controls were analyzed using cytokine arrays.

Main Results:

• IL-1β stimulation significantly upregulated IL-8 gene and protein expression in both nucleus pulposus (NP) and AF cells.
• IL-7 gene expression also increased in NP cells following IL-1β stimulation.
• AF tissues from patients with back pain exhibited significantly higher levels of IL-8, IL-7, and IL-10 compared to control tissues.

Conclusions:

• IVD cells, specifically NP and AF cells, are capable of producing key inflammatory cytokines.
• Elevated levels of IL-8, IL-7, and IL-10 in AF tissues are associated with discogenic back pain.
• These findings suggest that inflammatory mediators produced by IVD cells play a significant role in the pathophysiology of axial back pain.