Refined photobiomodulation therapy ameliorates inflammatory bowel disease via modulation of immune pathways and gut microbiota.

Abstract

BACKGROUND: Inflammatory bowel diseases (IBD), such as ulcerative colitis and Crohn's disease, are chronic conditions influenced by genetic and environmental factors. Current treatments are costly and not universally effective. This study aimed to evaluate the therapeutic potential of refined photobiomodulation (PBM) therapy by addressing limitations in light delivery and its impact on gut microbiota using a dextran sodium sulfate (DSS)-induced colitis mouse model. METHODS: PBM therapy was administered using an 830&#xa0;nm infrared LED with optimized light delivery protocols, including abdominal hair removal and a four-directional irradiation approach. DSS-induced colitis was established in mice, and therapeutic efficacy was assessed through histological analysis, transcriptomic profiling, immune marker expression, and gut microbiota diversity using 16S rRNA sequencing. RESULTS: PBM therapy significantly ameliorated DSS-induced colitis by reducing inflammatory cell infiltration, crypt damage, and ulceration (p&#xa0;<&#xa0;0.05). Colon length was restored, and disease activity index scores were reduced (p&#xa0;<&#xa0;0.001). Transcriptomic profiling revealed modulation of inflammatory pathways, including downregulation of NF-&#x3ba;B signaling and apoptosis-related genes. PBM decreased neutrophil activity (MPO levels) and immune cell marker expression while promoting gut microbiota richness (Chao1 index, p&#xa0;<&#xa0;0.05). PBM-treated mice exhibited altered microbial composition with increased abundance of protective taxa such as Bacteroides. CONCLUSIONS: Refined PBM therapy effectively alleviates DSS-induced colitis by modulating immune responses and gut microbiota composition. These findings highlight PBM as a promising non-invasive strategy for IBD management, warranting further translational studies.