Anti-inflammatory properties of N-acetylcysteine on lipopolysaccharide- activated macrophages

Introduction Innate immune cells play a role in modulating host immune response. Part of the macrophage inflammatory response is the release of an array of inflammatory cytokines, important molecules during the development of innate and adaptative immunity. Several antioxidant agents have been used in the control of the inflammatory response. Objective To evaluate the anti-inflammatory effect of N-acetylcysteine (NAC) on the expression and secretion of inflammatory cytokines and interleukin (IL)-10 in lipopolysaccharide (LPS)-activated THP-1 macrophages under mild oxidative conditions. Methods Macrophages were activated by LPS (0.1 and 1 μg/ml) for up to 24 h. The effect of 15 mM NAC was evaluated at 2, 4, 6 and 24 h. mRNA expression of tumor necrosis factor (TNF)-α, IL-1β, IL-6, IL-8 and IL-10 was assessed by real time PCR. The expression of the corresponding cytokines plus IL-12p70 was analyzed using a bead array for flow cytometry. Results NAC inhibits the inflammatory cytokines TNFα, IL-1β and IL-6 in LPS-activated macrophages under mild oxidative conditions. IL-10 mRNA and protein expression are strongly downregulated in NAC-treated cells, which may further modify the inflammatory cytokine profile. Conclusion NAC modulates immune functions during the inflammatory response. © 2011 Springer Basel AG.