Effect of dehydroepiandrosterone on lipopolysaccharide-induced interleukin-6 production in DH82 cultured canine macrophage cells

Objective: This study examined the effect of dehydroepiandrosterone (DHEA) on lipopolysaccharide (LPS)-stirnulated interleukin-6 (IL-6) production in the DH82 canine macrophage cell line. Study design: Cultured DH82 cells were stimulated with varying concentrations of LPS with or without DHEA for various times. Supernatant IL-6 levels were measured by enzyme-linked immunosorbent assay. and Cellular cytoplasmic I kappa B alpha protein expression measured by Western blot analysis. Results: LPS dose-dependently stimulated IL-6 production (p=0.016). Cells stimulated with 20 p g LPS showed a time-dependent increase of IL-6 concentration up to 10 h post-treatment (p = 0.007). Co-treatment of DH82 cells with 20 mu g LPS and various concentrations of DHEA for 14 h showed that up to 10 mu M DHEA dose-dependently decreased the IL-6 concentration (p = 0.007). Also, addition of 20 mu M DHEA to DH82 cells with 20 p g LPS time-dependently decreased the IL-6 concentration for tip to 14 h post-treatment (p = 0.018). Stimulation of cultured DH82 cells with 20 mu g LPS significantly decreased Cellular cytoplasmic I kappa B alpha expression, beginning at 30 min post-treatment and persisting to at least 2 h post-treatment (p = 0.012). However, co-treatment of cells with 20 mu g LPS and 20 mu M DHEA abroaated this effect until 2 h post-treatment. Conclusions: DHEA decreased the IL-6 concentration in the supernatant of LPS-stimulated DH82 cells by inhibiting the sequestration of I kappa B alpha, which is necessary for the activation of nuclear factor-kappa B. These findings provide new insights into the immunomodulatory effects of DHEA. (c) 2006 Elsevier Ireland Ltd. All rights reserved.