摘要Long-term exposure to ambient fine particulate matter(PM25)may increase the risk of neurotoxicity in human populations.However,research studies on the underlying mechanisms of chronic PM2.5-induced depression-like behaviors,and potential therapeutical strategies,remain scarce.In the present study,after long-term exposure to real-world PM2.5 for 15 weeks,male mice displayed depression-like behaviors,which were revealed using the open field and sucrose preference tests.Mechanistically,chronic PM2.5 exposure promoted astrocytic A1 polarization and disrupted reduction-oxidation balance in the mouse hippocampus.Furthermore,PM2.5-exposed mice displayed pathological damage to hippocampal neurons as well as the inhibition of nuclear factor erythroid 2-related factor 2 signaling.Astrocytic ablation of nuclear factor erythroid 2-related factor 2 exacerbated PM2.5-induced hippocampal neuronal injury in mice via the disruption of astrocyte-to-microglia communication;this finding was confirmed in mice with bilateral and unilateral hippocampal astrocytic Nfe2I2 knockdown.Importantly,the upregulation of nuclear factor erythroid 2-related factor 2 activation by procyanidin significantly ameliorated PM2.5-induced depression-like behaviors through the remodeling of astrocyte-to-microglia communication.Together,our findings shed light on the important role of hippocampal astrocytic nuclear factor erythroid 2-related factor 2 activation for maintaining astrocyte-to-microglia communication,and indicate potential research avenues for therapeutic strategies against PM2.5-induced depresson-like behaviors.