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

ObjectiveThis study examined the effect of dehydroepiandrosterone (DHEA) on lipopolysaccharide (LPS)-stimulated interleukin-6 (IL-6) production in the DH82 canine macrophage cell line.Study designCultured 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 IκBα protein expression measured by Western blot analysis.ResultsLPS dose-dependently stimulated IL-6 production (p = 0.016). Cells stimulated with 20 μg 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 μg LPS and various concentrations of DHEA for 14 h showed that up to 10 μM DHEA dose-dependently decreased the IL-6 concentration (p = 0.007). Also, addition of 20 μM DHEA to DH82 cells with 20 μg LPS time-dependently decreased the IL-6 concentration for up to 14 h post-treatment (p = 0.018). Stimulation of cultured DH82 cells with 20μg LPS significantly decreased cellular cytoplasmic IκBα 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 μg LPS and 20 μM DHEA abrogated this effect until 2 h post-treatment.ConclusionsDHEA decreased the IL-6 concentration in the supernatant of LPS-stimulated DH82 cells by inhibiting the sequestration of IκBα, which is necessary for the activation of nuclear factor-kappa B. These findings provide new insights into the immunomodulatory effects of DHEA.