Dexmedetomidine modulates peritoneal macrophage to attenuate lipopolysaccharide-induced inflammation.

PURPOSE: To investigate how Dexmedetomidine (Dex) modulates the function of peritoneal macrophages (PMs) to reduce lipopolysaccharide (LPS)-induced inflammation.

METHODS: The anti-inflammatory effect of Dex on LPS-stimulated PMs was assessed by examining its impact on their proliferation, phagocytosis, and polarization. Proliferation and phagocytic activity were measured using CCK-8 and Neutral Red staining assays, respectively. The levels of inflammatory mediators were quantified using ELISA. Additionally, macrophage polarization was evaluated via ELISA, flow cytometry, and Western blot analysis to identify shifts in macrophage phenotypes.

RESULTS: Dex increased the proliferation and phagocytic capabilities of PMs, thereby mitigating LPS-induced inflammation. It suppressed pro-inflammatory mediators, including tumor necrosis factor-α (TNF-α), interleukin-6 (IL-6), and high mobility group box 1 (HMGB1), while increasing levels of the anti-inflammatory cytokine interleukin-10 (IL-10). Furthermore, Dex promoted M2-type macrophage polarization, characterized by increased expression of IL-10, CD206, Arg-1, and CD11c. This effect was mediated through the JAK1/STAT6 signaling pathway, promoting M2 polarization, which was attenuated when JAK1 and STAT6 expression were downregulated.

CONCLUSION: Dex reduces LPS-induced inflammation in part by enhancing the proliferation, phagocytosis, and M2 polarization of PMs, with a key role for the JAK1/STAT6 pathway in promoting anti-inflammatory responses during sepsis.