Endotoxin Stimulates Interleukin-6 Production in Intestinal Epithelial Cells

Abstract

Objective: To test the hypothesis that endotoxin stimulates the release of interleukin-6 (IL-6) from intestinal epithelial cells and that this effect of endotoxin is regulated by prostaglandin E₂(PGE₂). Design: A rat intestinal crypt cell line, IEC-6, was cultured in the presence of lipopolysaccharide (LPS), 0.1 to 1.0 μg/mL, and/or PGE₂, 1 μmol/L. In other experiments, indomethacin, 20 μmol/L, was added to LPS-treated cells to block the effects of prostaglandins. Control wells contained medium alone. Levels of IL-6 were determined by the B9 murine hybridoma bioassay. Polymerase chain reaction was performed on RNA from control and LPS-treated cells to examine IL-6 message. Results: Lipopolysaccharide and PGE₂induced IL-6 release from IEC-6 cells in a dose- and time-dependent fashion, and the substances interacted synergistically. Addition of indomethacin blunted the effect of endotoxin on IL-6 production, consistent with a stimulatory role of PGE₂. Polymerase chain reaction demonstrated increased IL-6 messenger RNA in endotoxin-treated cells. Conclusions: Endotoxin and PGE₂stimulate IL-6 production in IEC-6 cells and interact synergistically. The endotoxin-stimulated IL-6 release may be regulated at the transcriptional level. (Arch Surg. 1994;129:1290-1295)