The Inhibitory Effect of Pterostilbene on Inflammatory Responses during the Interaction of 3T3-L1 Adipocytes and RAW 264.7 Macrophages

Chronic inflammation is characterized by the upregulation of proinflammatory cytokines in obese adipose tissue. Accumulations of adipose tissue macrophages enhance a chronic inflammatory state in adipose tissues. Many studies have indicated that the adipocyte-related inflammatory response in obesity is characterized by an enhanced infiltration of macrophages. The aim of this work was to study the inhibitory effects of garcinol and pterostilbene on the change in inflammatory response due to the interaction between 3T3-L1 adipocytes and RAW 264.7 macrophages. In the TNF-alpha-induced 3T3-L1 adipocyte model, garcinol and pterostilbene significantly decreased the mRNA expression of COX-2, iNOS, IL-6, and IL-1 beta and IL-6 secretion by suppressing phosphorylation of p-I kappa B alpha and p-p65. In a coculture model of 3T3-L1 adipocytes and RAW 264.7 macrophages, pterostilbene suppressed IL-6 and TNF-alpha secretion and proinflammatory mRNA expression and also reduced the migration of macrophages toward adipocytes. In the RAW 264.7 macrophage-derived conditioned medium (RAW-CM)-induced 3T3-L1 adipocyte and 3T3-CM-induced RAW 264.7 macrophage models, pterostilbene significantly decreased IL-6 and TNF-alpha secretion and proinflammatory mRNA expression (COX-2, iNOS, IL-6, TNF-alpha, PAT-I, CRP, MCP-1, resistin, and leptin). Our findings suggest that garcinol and pterostilbene may provide novel and useful applications to reduce the chronic inflammatory properties of adipocytes. We also found that pterostilbene inhibits proinflammatory responses during the interaction between 3T3-L1 adipocytes and RAW 264.7 macrophages.