LOCALIZATION OF TROXERUTIN IN THE VENOUS WALL MEASURED USING LASER-SCANNING MICROSCOPE

The vein wall is nourished by diffusion of blood nutrients from the lu men and from the vasa vasorum. It is likely that drugs take the same w ays to reach and diffuse through the vessel wall. Thus the uptake of a drug with affinity for the vein wall should give information on its t ransport to the tissue. This study aimed to explore troxerutin uptake by the long saphenous vein. Troxerutin is a naturally fluorescent flav onoid which has been known to improve subjective signs of patients wit h chronic venous insufficiency. Nine patients undergoing surgical trea tment of varicosis were enrolled in the study. They received for the l ast 4 days before surgery either 3 500 mg of troxerutin (n = 4) or 1 0 00 mg twice daily (n = 2). Three patients as controls did not receive any drug. Two samples from tigh and claf long saphenous vein were harv ested in each patients and investigated with a confocal laser scanning microscope developped by our institute measuring the fluorescence emi tted by troxerutin after excitation by a 458 nm wavelength laser-beam. The intensity of the overall fluorescence was significantly higher in the treated groups (p < 0.001) and slightly higher in the patient who received 3 500 mg of troxerutin than with the lower dosage. The outer wall region provided the highest fluorescence in the treated group wh ile a significant difference was observed in the fluorescence of the m edial region between treated and control group. These results showed a marked affinity of troxerutin for the venous wall. The highest uptake in the outer wall region is likely to result from transport through v asa vasorum, owing to the rheologic properties of the drug. The signif icant medial fluorescence may account for the venous tone improvement with the drug.