Down-regulation of IL-6, IL-8, TNF-α and IL-1β by glucosamine in HaCaT cells, but not in the presence of TNF-α

There is considerable evidence that glucosamine exerts an inhibitory effect on inflammatory cytokine expression in cells Glucosamine has been recommended as a promising anti-inflammatory modulator, which has been applied in clinical trials for attenuation of the inflammatory process However, it is unknown whether glucosamine reduces the expression of TNF-alpha-induced inflammatory cytokines in HaCaT cells The anti-inflammatory effects of curcumin in HaCaT cells have been extensively investigated in several studies Thus, in this study we investigated the expression of IL-6, IL-8, TNF-alpha and IL-1 beta in glucosamine-treated HaCaT cells, and the effects of glucosamine were compared to those of curcumin-treated HaCaT cells Our data showed that the expression of IL-6, IL-8, TNF-alpha and IL-1 beta was decreased by glucosamine treatment in the HaCaT cells In contrast, the expression of IL-6, IL-8, TNF-alpha and IL-1 beta was not attenuated by glucosamine treatment in the TNF-alpha-treated HaCaT cells Notably, curcumin induced an increased expression of IL-8 and IL-1 beta in the HaCaT cells, but not that of IL-6 and TNF-alpha On the other hand, curcumin attenuated the expression of IL-6 and IL-8 in the TNF-alpha-treated HaCaT cells Our data indicated that glucosamine induced the down-regulation of IL-6, IL-8, TNF-alpha and IL-1 beta expression in the HaCaT cells However, the stimulation of TNF-alpha abolished the inhibitory effects of glucosamine on the expression of inflammatory cytokines in the HaCaT cells Thus, even though glucosamine induces the down-regulation of inflammatory cytokines in HaCaT cells, the anti-inflammatory role of glucosamine in TNF-alpha-mediated inflammatory skin diseases should be investigated