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

Abstract

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. 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. Macrophages were activated by LPS (0.1 and 1μg/ml) for up to 24h. The effect of 15mM NAC was evaluated at 2, 4, 6 and 24h. 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. 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. NAC modulates immune functions during the inflammatory response.