Cyanidin-3- O-glucoside promotes late-stage venous thrombus resolution in mice, accompanied by reduced macrophage M1-associated inflammation and attenuated HIF-1α-linked signaling

Deep vein thrombosis (DVT) is characterised by thrombus formation in the deep veins, and efficient thrombus resolution is essential to restore venous patency and prevent life-threatening complications. Cyanidin-3-O-glucoside (C3G), a major dietary anthocyanin with anti-inflammatory and antioxidant activities, has not previously been investigated in the context of venous thrombus resolution. Here, we examined the effects of C3G on stasis-induced DVT in mice and explored the underlying mechanisms, with a focus on macrophage function and hypoxia-inducible factor 1α (HIF-1α) signalling. Prophylactic oral C3G markedly reduced thrombus weight, length and cross-sectional area 14 days after inferior vena cava ligation, accompanied by increased intrathrombotic CD68⁺ macrophage abundance, suppression of M1 macrophage polarization and attenuation of intrathrombotic inflammatory responses. C3G increased systemic and local superoxide dismutase activity, decreased lactate and malondialdehyde levels and downregulated HIF-1α together with its downstream glycolytic enzymes Pyruvate Kinase M2 and Lactate Dehydrogenase A within thrombi. In bone marrow-derived macrophages, C3G selectively inhibited lipopolysaccharide and interferon-γ-induced M1 polarization and cytokine production without affecting interleukin-13-driven M2 polarization. In a CoCl₂-induced hypoxia-mimetic model, C3G reduced Reactive Oxygen Species generation, restored antioxidant capacity, limited Apoptosis and reduced markers of hypoxia and glycolysis regulated by HIF-1α. These findings indicate that C3G is associated with late-stage thrombus resolution in parallel with modulating macrophage polarization and HIF-1α-mediated metabolic adaptation, supporting further evaluation of this food-derived compound as a candidate adjunct for modulating the thrombus microenvironment.