Effects of N-acetyl chitooligosaccharides (NACOS) on gene expression of TNF-α, IL-6, IL-1β, and protein level of IL-1β in RAW264.7 macrophages. The RAW264.7 cells were treated with NACOS (100 µg/mL) or LPS (1 µg/mL) for 8 h. Gene expressions were measured by RT-qPCR. Gene expressions of (A) TNF-α; (B) IL-6; and (C) IL-1β, following treatment with NACOS. (D) Western blot analysis of IL-1β following treatment with NACOS for 8 h. (E) IL-1β protein levels following treatment with NACOS for 8 h, evaluated by densitometry analysis of the blot. Data were normalized to that of β-actin and are presented as the fold induction 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 control group.