Effect of astaxanthin on inflammatory response of RAW264.7 cells induced by lipopolysaccharide and its mechanism

Objective  To study the effect of astaxanthin (AST) on the inflammatory response of RAW264.7 cells induced by lipopolysaccharide (LPS) and the mechanism, and provide a theoretical basis for using AST in inflammation therapy.

Method  Different concentrations of LPS and AST were used to treat RAW264.7 cells for different time. The optimal treatment concentration and time were determined by MTT method. After applying the optimal treatment, the secretion, mRNA relative expression and protein relative expression of inflammatory factors were detected by ELISA, fluorescence quantitative PCR and Western blot method respectively.

Result  When treated with 100 μmol/L AST and 2 μg/mL LPS for 3 h, the viability of RAW264.7 cells was at the peak. Compared with the control group, the secretion of TNF-α, IL-6 and Caspase-1 in RAW264.7 cells of LPS group reduced by 12.83%, 9.66% and 20.80% respectively(P<0.05). LPS promoted the expression of TLR4/MyD88/NF-κB pathway-related proteins with relative expression of TLR4 and NF-кB p65 proteins enhanced by 195.40% and 226.95% respectively(P<0.05). Compared with LPS group, AST had inhibitory effects on the secretion and mRNA expression of inflammatory factors in AST+LPS group, and the relative expression of TLR4, MyD88 and NF-кB p65 proteins reduced by 54.99%, 45.70% and 28.20% respectively (P<0.05).

Conclusion  AST pre-protection can inhibit the expression of TLR4/MyD88/NF-κB pathway-related proteins, thereby alleviate the inflammatory response in RAW264.7 cells induced by LPS.