As　a　major　pollutant　of　air　pollution，fine　atmospheric　pollutants（PM2.5）are　easily　deposited　in　alveolar　cells　or　enter　the　blood　stream　due　to　their　small　particle　size　and　large　specific　surface　area.　Available　studies　have　reported　that　many　respiratory　diseases　are　associated　with　exposure　to　environmental　PM2.5.　Alveolar　macrophages，as　an　intrinsic　immune　cell，are　the　first　line　of　defense　against　foreign　pollutants　and　pathogenic　microorganisms.　In　this　study，THP-1　cells　were　used　as　a　human　macrophage　model　to　investigate　the　mechanism　of　inflammatory　response　in　macrophages　induced　by　PM2.5　exposure.　3967　differentially　expressed　genes（DEGs）were　screened　by　RNA　sequencing　in　PM2.5-exposed　THP-1　cells.　Through　GO　analysis　and　KEGG　enrichment　analysis　of　these　DEGs，it　was　found　that　multiple　pathways　were　related　to　immune　response　and　inflammatory　signals.　The　protein-protein　interaction　analysis　of　230　genes　related　to　inflammatory　pathway　was　further　carried　out，and　CXCL8（C-X-C　motif　chemokine　ligand　8）gene　was　found　to　be　at　the　core　of　the　interaction.　Then　the　expression　of　CXCL8　gene　was　verified　by　real-time　PCR　and　ELISA　in　PM2.5-　exposed　THP-1　cells.　It　was　found　that　in　the　first　24　hours　of　low　concentration　exposure，the　relative　transcription　level　and　secretion　level　of　CXCL8　increased　with　the　increase　of　exposure　time　and　concentration　of　PM2.5.　The　study　has　shown　that　CXCL8　is　significantly　expressed　in　THP-1　cells　exposed　to　PM2.5　and　is　at　the　core　of　the　interaction　of　pathway　proteins，suggesting　that　CXCL8　plays　an　important　role　in　the　lung　inflammatory　response　induced　by　PM2.5　exposure.　©　2023　Science　Press.　All　rights　reserved.