Importance of IL-6, MMP-1, IGF-1, and BAX Levels in Lumbar Herniated Disks and Posterior Longitudinal Ligament in Patients with Sciatic Pain

Abstract

Purpose: The aim of this study was to evaluate prognostic importance of interleukin-6 (IL-6), matrix metalloproteinase (MMP)-1, insulin-like growth factor (IGF)-1, and Bcl-2-associated X protein (BAX) levels in biopsy specimens taken from the intervertebral disk specimens and the posterior longitudinal ligaments of patients with sciatic pain.

Methods: The specimens of the intervertebral disk and the posterior longitudinal ligament were obtained from 52 patients undergoing herniectomy and diskectomy at the Neurosurgery Department of the Abant Izzet Baysal University Izzet Baysal Training and Research Hospital between April 2012 and February 2014. The immunohistochemical expressions of IL-6, MMP-1, IGF-1, and BAX were evaluated in three categories: mild, moderate, and intense.

Results: The IL-6 expression in the intervertebral disk specimens was intense in the sequestration group when compared with that of the "protrusion" and "extrusion" groups. The intervertebral disk specimens in "extrusion" and "sequestration" groups were stained intensely for MMP-1. The IGF-1 expression was stained intensely in the intervertebral disk tissue of the extrude group patients. For the "extrusion" and "sequestration" groups, the intervertebral disk specimens were stained intensely for BAX compared with the protrude group. The IL-6 expression in the posterior longitudinal ligament specimens was more intense in the "sequestration" and "extrusion" groups when compared with that of the protrude group. The MMP-1 expressions were milder in the sequestration group when compared with that of the "extrusion" and "protrusion" groups.

Conclusions: Our findings suggest that the cytokines, enzymes, growth factors, and proapoptotic proteins, such as IL-6, MMP-1, IGF-1, and BAX, may be critical factors in the pathophysiology of the degeneration of the intervertebral disks in patients with symptomatic degenerative disk disease.

Keywords: Degeneration; Herniated disk; Immunohistochemistry; Insulin-like growth factor-1; Interleukin-6; Intervertebral disk.