Abstract
Background: Macrophage polarization is an important regulatory mechanism of ventricular remodeling. Studies have shown that sinapic acid (SA) exerts an anti-inflammatory effect. However, the effect of SA on macrophages is still unclear. Objectives: The purpose of the study was to investigate the role of SA in macrophage polarization and ventricular remodeling after myocardial infarction (MI). Methods: An MI model was established by ligating the left coronary artery. The rats with MI were treated with SA for 1 or 4 weeks after MI. The effect of SA on bone marrow-derived macrophages (BMDMs) was also observed in vitro. Results: Cardiac systolic dysfunction was significantly improved after SA treatment. SA reduced MCP-1 and CCR2 expression and macrophage infiltration. SA decreased the levels of the inflammatory factors TNF-α, IL-1α, IL-1β, and iNOS and increased the levels of the M2 macrophage markers CD206, Arg-1, IL-10, Ym-1, Fizz-1, and TGF-β at 1 week after MI. SA significantly increased CD68+/CD206+ macrophage infiltration. Myocardial interstitial fibrosis and MMP-2 and MMP-9 levels were decreased, and the sympathetic nerve marker TH and nerve sprouting marker GAP43 were suppressed after SA treatment at 4 weeks after MI. The PPARγ level was notably upregulated after SA treatment. In vitro, SA also increased the expression of PPARγ mRNA in BMDMs and IL-4-treated BMDMs in a concentration-dependent manner. SA enhanced Arg1 and IL-10 expression in BMDMs, and the PPARγ antagonist GW9662 attenuated M2 macrophage marker expression. Conclusions: Our results demonstrated that SA attenuated structural and neural remodeling by promoting macrophage M2 polarization via PPARγ activation after MI.