Time course of microvalve pathophysiology in high pressure low flow model of venous insufficiency and the role of micronized purified flavonoid fraction

BACKGROUND The aim of this study was to characterize, in an experimental model, the mechanisms involved in the initiation of venous insufficiency at the level of microvenous valve and whether they can be influenced by early treatment with micronized purified flavonoid fraction (MPFF). METHODS The external right iliac vein of 78 male golden Syrian hamsters was ligated to induce chronic venous insufficiency. Internal venular diameter as well as leukocyte-endothelium-interaction (leukocytes sticking after staining with rhodamine 6G), were assessed using an intravital microscope. In the second part of the study 30 animals were divided into three groups and underwent: ligation plus MPFF, ligation plus 10% lactose solution (vehicle), or sham operation. Treatment with MPFF 100 mg/kg/day or vehicle started 2 days before ligation and lasted for 7 days. Venular diameter and number of adherent leukocytes were assessed 5 days post-ligature. RESULTS Venular diameter increased immediately after ligature and reached a maximum at 4 hours (P