IL-4 attenuates myocardial infarction injury by promoting M2 macrophage polarization.

IL-4, an immunoregulatory cytokine, plays a role in various cellular pathways and is known to regulate M2 macrophage polarization. Numerous studies have suggested that promoting the polarization of macrophages toward the M2 phenotype is beneficial for myocardial infarction (MI) recovery. However, whether IL-4 can achieve therapeutic effects in MI by regulating M2 macrophage polarization remains unclear. In this study, the authors observed that IL-4 increased the proportion of M2 macrophages in the ischemic myocardium compared to the PBS group. Additionally, IL-4 reduced the infiltration of inflammatory cells and the expression of proinflammatory-related proteins, while enhancing the expression of genes associated with tissue repair. Furthermore, IL-4 facilitated the recovery of cardiac function and reduced fibrosis in the post-MI phase. Importantly, when macrophages were depleted, the therapeutic benefits of IL-4 mentioned above were attenuated. These findings provide evidence for the effectiveness of IL-4 in treating MI through the regulation of M2 macrophage polarization, thereby encouraging further development of this therapeutic approach.