The combination effects of acetaminophen and N-acetylcysteine on cytokines production and NF-κB activation of lipopolysaccharide-challenged piglet mononuclear phagocytes in vitro and in vivo

Lipopolysaccharide (LPS) is a known activator of mononuclear phagocytes. LPS activates the pro-inflammatory gene expression and induces the release of mediators/cytokines by TLR4-NF-κB signaling pathway. The purpose of this study was to investigate the effects of acetaminophen (AAP) and N-acetylcysteine (NAC), individually as well as in combination on LPS-induced cytokines production and NF-κB activation in piglets. AAP (0.125–1.0 mM) and NAC (0.0625–1.0 mM) down-regulate the expression of cytokines and inhibit NF-κB p65 protein transfer from the cytoplasm to the nucleus in vitro. NAC enhances the inhibition action of AAP on cytokines expression in vitro. IL-6 in piglet plasma of the AAP group (mixed feed concentration of 600 mg/kg) was significantly reduced (P < 0.05) at 3 h after LPS-challenge as compared with the LPS control group. IL-10 also significantly reduced (P < 0.05) at 24 h after LPS injection. The levels of inflammatory cytokines (TNF-α, IL-1β, IL-6, and IL-10) in piglet plasma of the NAC group (mixed feeding concentration of 1200 mg/kg) were significantly lower at 3 h after LPS stimulation (P < 0.05). IL-10 was significantly decreased in the NAC group at 24 h after LPS stimulation (P < 0.05). AAP or NAC treated alone could reduce the NF-κB p65 concentration ratio. The levels of cytokines (TNF-α, IL-1β, IL-6, and IL-10) in the group with piglet plasma of AAP (mixed feed concentration of 600 mg/kg) plus NAC (mixed feeding concentration of 1200 mg/kg) group were significantly lower (P < 0.05) at 3 h after LPS activation. The level of IL-10 in the group with AAP plus NAC was significantly lower (P < 0.05) at 24 h after LPS stimulation, while the rest of the inflammatory cytokines were returned to the original levels. The NF-κB p65 concentration ratio had significantly reduced (P < 0.05) when AAP and NAC were used in combination. In summary, NAC could enhance the anti-inflammatory effects of AAP both in vitro and in vivo.