Macrophage Lactylation Mediates Phenotypic Polarization To Regulate Pulp Inflammation

Elevated lactate associates with pulp inflammation, but mechanism unclear. This study explores how macrophage lactylation regulates pulp inflammation progression. Lactate levels in dental pulp tissues were quantified using a high-sensitivity assay. immunohistochemistry (IHC) localized pan-lactylation (Pan-Kla), M2 macrophage marker CD206, and proinflammatory cytokine IL-6, with dual immunofluorescence confirming Pan-Kla co-localization with pan-macrophage marker CD68 and CD206. In a murine experimental pulpitis model(0-72h), integrating hematoxylin-eosin (HE) staining and Pan-Kla IHC to correlate lactylation dynamics with inflammatory progression. A time-course inflammatory pulp cell model (0-72h) was established,intracellular/extracellular lactate flux was systematically monitored. In a macrophage-pulp cell indirect co-culture system, lactate transmembrane transport efficiency was assessed via intra/extracellular lactate quantification. Western blot evaluated Pan-Kla, CD206, and M1 marker iNOS to define lactate-mediated lactylation and polarization. Transcriptomic profiling identified differentially expressed genes, with KEGG enrichment highlighting glycolytic reprogramming pathways. Blockade of monocarboxylate transporters (MCTs) suppressed lactate uptake, followed by Western blot analysis of Pan-Kla/CD206/iNOS. qRT-PCR quantified glycolytic enzymes (LDHA, HK2, PKM2) and inflammatory mediators (IL-6, CXCL-10). Concurrent oxygen consumption rate (OCR) and extracellular acidification rate (ECAR) were measured. Scanning transmission electron microscopy (STEM) analyzed mitochondrial ultrastructure. Pan-Kla spatiotemporal heterogeneity peaks at 12h with CD206+ co-localization; lactate blockade reduces Pan-Kla and CD206, inhibits LDHA and PKM2, induces mitochondrial damage. Lactylation-driven metabolic reprogramming modulates macrophage polarization in pulpitis.