Long wavelength light exposure reduces systemic inflammation coagulopathy, and acute organ injury following polytrauma in mice.

BACKGROUND: Evidence suggests that variation in light exposure strongly influences the dynamic of inflammation, coagulation, and the immune system. Polytrauma induces systemic inflammation that can lead to end-organ injury. Here, we hypothesize that alterations in light exposure influence post-trauma inflammation, coagulopathy, and end-organ injury. METHODS: Study Type: Original Research Article. Level of Evidence: Basic Science (Level IV).C57BL/6 mice underwent a validated polytrauma and hemorrhage model performed following 72 hours of exposure to red (617 nm, 1,700lux), blue (321 nm, 1,700lux), and fluorescent white light (300lux) (n = 6-8/group). The animals were sacrificed at 6 h post-trauma. Plasma samples were evaluated and compared for pro-inflammatory cytokine expression levels, coagulation parameters, markers of liver and renal injury, and histological changes (Carstairs staining). One-way ANOVA statistical tests were applied to compare study groups. RESULTS: Pre-exposure to long-wavelength red light significantly reduced the inflammatory response at 6 hours post-polytrauma compared to blue and ambient light, as evidenced by decreased levels of IL-6, MCP-1 (both p < 0.001), liver injury markers (ALT, p < 0.05), and kidney injury markers (cystatin C, p < 0.01). Additionally, Carstairs staining of organ tissues revealed milder histological changes in the red light-exposed group, indicating reduced end-organ damage. Furthermore, PT was significantly lower (p < 0.001) and fibrinogen levels were better maintained (p < 0.01) in the red light-exposed mice compared to those exposed to blue and ambient light. CONCLUSION: Prophylactic light exposure can be optimized to reduce systemic inflammation, coagulopathy and minimize acute organ injury following polytrauma. Understanding the mechanisms by which light exposure attenuates inflammation may provide a novel strategy to reducing trauma related morbidity.