N-acetyl cysteine protects HUVECs against lipopolysaccharide-mediated inflammatory reaction by blocking the NF-κB signaling pathway

Abstract

The purpose of the study was to explore the potential protective effects of N- acetylcysteine (NAC) against lipopolysaccharide (LPS)-induced inflammatory injury to human umbilical vein endothelial cells (HUVEC s). It was also assessed whether the underlying mechanism of this protective effect is mediated via suppression of the nuclear factor-kappa B (NF-κB) signaling pathway. Cell viability of HUVEC s treated with different concentrations of NAC was assessed using Cell Counting Kit-8 (CC K-8) assay. The mRNA expression of inflammatory factors [interleukin-8 (IL- 8), tumor necrosis factor α (TNF-α), inducible nitric oxide synthase (iNO S), and intercellular cell adhesive molecule 1 (ICA M-1)] were assessed using real time semi-quantitative polymerase chain reaction. Protein expression levels of TNF-α and IL- 8 were assessed using enzyme-linked immunosorbent assay. Protein expression levels of ICA M-1 and the NF-κB signaling pathway were assessed using western blotting. Nitric reductase method was used to quantify nitric oxide (NO) and iNO S. LPS stimulated the production of TNF-α, IL- 8, NO, and ICA M-1 by HUVEC s. Moreover, LPS induced activation of the NF-κB signaling pathway and increased the protein expression of phosphorylated p65. However, pretreatment of HUVEC s with NAC significantly attenuated the increase in the expression of inflammatory factors and the level of phosphorylated p65; this indicated that NAC prevented the activation of the NF-κB signaling pathway. The present findings indicated that NAC protects HUVECs against LPS-mediated inflammatory reaction and alleviates inflammation. The underlying mechanism is related to the NF-κB signaling pathway. NAC appears to be a promising agent for prevention and treatment of inflammatory diseases.