Lipids Extracted from Aptocyclus ventricosus Eggs Possess Immunoregulatory Effects on RAW264.7 Cells by Activating the MAPK and NF-κB Signaling Pathways

This study was conducted to evaluate the potential anti-inflammatory and immune-enhancement properties of lipids derived from <i>Aptocyclus ventricosus</i> eggs on RAW264.7 cells. Firstly, we determined the fatty acid compositions of <i>A. ventricosus</i> lipids by performing gas chromatography analysis. The results showed that <i>A. ventricosus</i> lipids contained saturated fatty acids (24.37%), monounsaturated fatty acids (20.90%), and polyunsaturated fatty acids (54.73%). They also contained notably high levels of DHA (25.91%) and EPA (22.05%) among the total fatty acids. Our results for the immune-associated biomarkers showed that <i>A. ventricosus</i> lipids had immune-enhancing effects on RAW264.7 cells. At the maximum dose of 300 µg/mL, <i>A. ventricosus</i> lipids generated NO (119.53%) and showed greater phagocytosis (63.69%) ability as compared with untreated cells. <i>A. ventricosus</i> lipids also upregulated the expression of <i>iNOS</i>, <i>IL-1β</i>, <i>IL-6</i>, and <i>TNF-α</i> genes and effectively upregulated the phosphorylation of MAPK (JNK, p38, and ERK) and NF-κB p65, indicating that these lipids could activate the MAPK and NF-κB pathways to stimulate macrophages in the immune system. Besides their immune-enhancing abilities, <i>A. ventricosus</i> lipids significantly inhibited LPS-induced RAW264.7 inflammatory responses via the NF-κB and MAPK pathways. The results indicated that these lipids significantly reduced LPS-induced NO production, showing a decrease from 86.95% to 38.89%. Additionally, these lipids downregulated the expression of genes associated with the immune response and strongly suppressed the CD86 molecule on the cell surface, which reduced from 39.25% to 33.80%. Collectively, these findings imply that lipids extracted from <i>A. ventricosus</i> eggs might have biological immunoregulatory effects. Thus, they might be considered promising immunomodulatory drugs and functional foods.