Transcriptomic profiling of LPS-stimulated RAW264.7 macrophages after low-intensity ultrasound treatment

Macrophage-mediated inflammation is a key pathological feature of the injured tendon-to-bone interface after rotator cuff tear. In this study, we performed bulk RNA sequencing to investigate the transcriptional effects of low-intensity ultrasound on inflammatory macrophage activation. RAW264.7 macrophages were stimulated with lipopolysaccharide to establish an inflammatory macrophage model and were treated with ultrasound at 50 mW/cm² under fixed low-intensity pulsed ultrasound settings. RNA-seq was performed to compare LPS-stimulated macrophages with or without 50 mW/cm² ultrasound treatment. Transcriptomic analysis showed that 50 mW/cm² ultrasound substantially reprogrammed the inflammatory transcriptional state of LPS-stimulated RAW264.7 macrophages. Multiple inflammation-associated genes, including Il1a, Il12b, Tnf, Il6, Ccl7 and Ccl4, were downregulated after ultrasound treatment. Gene Ontology enrichment analysis indicated suppression of inflammation-related biological processes, including immune system process, immune response, response to lipopolysaccharide and regulation of inflammatory response. Gene set enrichment analysis further revealed negative enrichment of the TNF signaling pathway and NF-κB signaling pathway. These data provide transcriptomic evidence that 50 mW/cm² ultrasound suppresses macrophage inflammatory activation through inhibition of canonical inflammatory signaling pathways.