Dexmedetomidine relieves LPS-induced acute lung injury by boosting HIF-1a/ACOD1 driven anti-inflammatory macrophage polarization.

Acute lung injury (ALI) is a common and life-threatening lung disease. This study investigated the mechanism by which dexmedetomidine (Dex) alleviates lipopolysaccharide (LPS)-induced ALI, focusing on its regulation of macrophage autophagy and polarization. Initially, a mouse model of LPS-induced ALI was pretreated with Dex. Pulmonary function, histopathological changes, apoptosis, macrophage numbers in bronchoalveolar lavage fluid (BALF), M1/M2 macrophage ratios, iNOS/Arg-1/LC3/P62 fluorescence intensity, and autophagy flux were assessed. Subsequently, RAW264.7 macrophages were treated with LPS and Dex, transfected with si-ACOD1 or si-HIF-1α, and co-cultured with mouse pulmonary microvessel endothelial cells (MPMVECs). The results showed that Dex relieved autophagy flux blockage and promoted autophagy in ALI mice. LPS promoted ACOD1 and HIF-1α levels, and Dex further enhanced their levels to boost macrophage autophagy and M2 polarization. ACOD1 was transcriptionally regulated by HIF-1α. Collectively, Dex mitigated LPS-induced MPMVEC injury and ALI by enhancing HIF-1α-mediated ACOD1 transcription, thus promoting macrophage autophagy and M2 polarization.