Abstract 523: The Effects of Spontaneous Exercise on Murine Model of Deep Vein Thrombosis

Abstract

Introduction: Recent studies suggest physical activity may have beneficial effects on deep vein thrombosis (VT). Long-term moderate exercise has been shown to reduce inflammatory cytokines and attenuate plasma fibrinogen compared to uninterrupted sitting. However, the effect exercise may have in VT is unknown. Our objective is to quantify the effects of prophylactic exercise on the thrombotic process in a murine model of VT. Methods: C57BL6 male mice were either provided in-cage running wheels (E: n=6) starting 2 weeks prior to and continuously following VT induction, or no wheel exposure (C: n=4). VT was induced with the electrolytic inferior vena cava model (EIM), which induces thrombosis in the continuous presence of blood flow. MR images were acquired days 2 (acute) or 6 (chronic) post VT using a T2-weighted sequence sensitive to edema-related fluid, then the thrombi were harvested for histology. Results: Four of six mice engaged in exercise. Three of four mice continued running after thrombus induction, with reduced activity (88 ± 11% reduction). While thrombus volume was not significantly different between groups, the volume of thrombus exhibiting high T2 signal was reduced by ~57% at day 6 in exercising mice, suggesting a decreased inflammatory response with exercise (C 0.81 ± 0.13 mm 3 vs. E 0.35 ± 0.07 mm 3 , p =0.08). Fibrin content, assessed by Picro-Mallory staining, was reduced by 60% at day 2 in exercising mice (C 2.08 ± 0.29 um 2 vs. E 0.83 ± 0.45 um 2 , p =0.09). Conclusion: Our results suggest that exercise may reduce inflammation in VT and lead to less fibrin-rich clots. Future studies will increase the number of animals, investigate inflammatory components, and extend to more chronic time points. Understanding the impact of exercise on specific thrombotic components could lead to better recommendations for patients with DVT.