Curcumin Change Macrophage Polarization State By Activating PPAR-Γ Pathways

Objective: Obesity and chronic inflammatory state are associated withinsulin resistance. The adipose tissue macrophage infiltration andpolarization state change is an important step for inflammation. Curcumin isa natural PPAR-γ agonist, and can improve the inflammation associated withobesity. This study aims to investigate the effects of curcumin on RAW264.7macrophage cell line polarization and inflammatory states, and to explorethe possible mechanism of action.Methods: The study selected the RAW264.7cell lines, they weredivided into four groups: normal control group, intervention group with FFA,intervention group with FFA+curcumin, intervention group with FFA+curcumin+PPAR-γ antagonists GW9662. After drug intervention for24hours, the total RNA were extracted from cells of all groups, real-timequantitative PCR technique was used to detect the mRNA expression level ofCD11c, CD206, TNF-α,Arg-1; the total protein were extracted from cells ofall groups, western blot technique was used to detect the protein expressionlevel of TNF-α, Arg-1; cells of all groups were collected, flow cytometrywas used to detect CD11c, CD206phenotype. SPSS17.0software is used to analyze the differences of testing indexes in all group.Results: Compared with the control group，the level of CD11c、TNF-αmRNA and TNF-α protein in intervention group with FFA were significantlyincreased(P<0.05)，the level of CD206、Arg–1mRNA and Arg–1protein inintervention group with FFA were significantly decreased(P<0.05).Compared with the intervention group with FFA，the level of CD11c、TNF-αmRNA and TNF-α protein in the FFA+curcumin group were significantlydecreased (P<0.05), the level of CD206、Arg–1mRNA and Arg–1protein inthe intervention group with free fatty acid and curcumin were significantlyincreased(P<0.05). Compared with the intervention group with free fattyacid and curcumin，the level of CD11c、TNF-α mRNA and TNF-α proteinin the intervention group with free fatty acid，curcumin and GW9662weresignificantly increased(P<0.05)，the level of CD206、Arg–1mRNA andArg–1protein in the FFA+curcumin+GW9662group were significantlydecreased(P<0.05).Conclusions: Curcumin can promote M2macrophages polarization,increase the expression of M2macrophages related markers, reduce theexpression of M1macrophages related markers. Curcumin promote M2macrophage polarization is mainly by activating PPAR-γ pathway, specificinhibition of PPAR-γ pathways can offset the anti-inflammatory action ofcurcumin.