Long wavelength light exposure reduces systemic inflammation coagulopathy and acute organ injury following multiple injuries in mice

Abstract

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.