Effects of N-acetyl chitooligosaccharides (NACOS) pretreatment on the phosphorylation of IκBα and NF-κB p65 in lipopolysaccharide (LPS)-induced RAW264.7 macrophages. RAW 264.7 cells were pretreated with the similar concentrations of NACOS (100 µg/mL), chitosan oligosaccharides (COS) (100 µg/mL), or LPS (1 µg/mL) for 24 h and then co-incubated with LPS for 8 h. (A) Western blot analysis of cellular IκBα and phosphorylated IκBα. (B) Cellular phosphorylated IκBα protein levels based on densitometry analysis of the blot. (C) Western blot analysis of nucleic phosphorylated NF-κB p65. (D) Nucleic phosphorylated NF-κB p65 protein levels based on densitometry analysis of the blot. Data were normalized to β-actin or Lamin B1, and presented as the induction fold, compared with the control group. Values are presented as the mean ± SD (n = 3). * p < 0.05; ** p < 0.01; *** p < 0.001, compared with the only LPS-treated group.