Murine nucleus pulposus-derived cells secrete interleukins-1-beta, -6, and -10 and granulocyte-macrophage colony-stimulating factor in cell culture.

STUDY DESIGN

Cultures established from murine disc-derived cells were stimulated by lipopolysaccharide. The cells' capacity to secrete proinflammatory cytokines and interleukin-10 with and without lipopolysaccharide stimulation was determined using enzyme-linked immunosorbent assays.

OBJECTIVES

To determine the capacity of disc-derived cells to secrete proinflammatory cytokines, and the effect of lipopolysaccharide stimulation on such secretion.

SUMMARY OF BACKGROUND DATA

The pathophysiology of compressive radiculopathy is unclear. Inflammation is a possible explanation. Proinflammatory cytokine secretion was demonstrated in herniated nucleus pulposus. It is unknown whether these cytokines are secreted from disc-derived cells or from infiltrating inflammatory cells in the herniated nucleus pulposus.

METHODS

Discs were microsurgically harvested from inbred mice and cut to allow the nucleus pulposus to establish cell culture. A study group was exposed to lipopolysaccharide stimulation. Media were harvested from the study and control groups 24 hours later. Secretion of interleukins-1-, -6, and -10, granulocyte-macrophage colony-stimulating factor, and tumor necrosis factor-alpha were determined using enzyme-linked immunosorbent assays.

RESULTS

Basal secretion of interleukins-6 and -10, but no basal secretion of interleukin-1-, granulocyte-macrophage colony-stimulating factor, or tumor necrosis factor-alpha was detected. Secretion of interleukin-1- rose from zero to 27.69 pg/10(5) cells, and granulocyte-macrophage colony-stimulating factor secretion rose from zero to 9.77 pg/10(5) cells after lipopolysaccharide stimulation. A 75-fold increase in interleukin-6 secretion and a 150-fold increase in interleukin-10 secretion were detected after stimulation with lipopolysaccharide. No tumor necrosis factor-alpha secretion was detectable. All result had high statistical significance (all P < 0.001).

CONCLUSIONS

Cultured murine disc-derived cells have the capacity to secrete proinflammatory cytokines and interleukin-10 in the absence of inflammatory cells. This finding supports the hypothesis that disc-derived cells are capable of initiating or amplifying an inflammatory process.