Inhibitory effect of the Ruscus extract and of the flavonoid hesperidine methylchalcone on increased microvascular permeability induced by various agents in the hamster cheek pouch.

The Ruscus extract and the flavonoid hesperidine methylchalcone (HMC) are used in treatment of venous insufficiency. In the present study, we used the hamster cheek pouch preparation and investigated the effects of these substances on increased microvascular permeability induced by bradykinin, histamine, and leukotriene B4 (LTB4) applied topically. Experiments were performed on male hamsters; 30 min after completion of the cheek pouch preparation, fluorescein-labeled dextran [molecular weight (mol wt) 150,000] was given intravenously (i.v.). Bradykinin, histamine, and LTB4 increased the number of fluorescent vascular leakage sites from postcapillary venules, evidence for an increase in macromolecular permeability, which was quantified in ultraviolet (UV)-light microscope as the number of leaky sites in the prepared area. Ruscus extract and HMC, given i.v., significantly inhibited the macromolecular permeability-increasing effect of bradykinin, LTB4, and histamine. Ruscus extract, applied topically, dose dependently inhibited the macromolecular permeability-increasing effect of histamine. Our results show that Ruscus extract and HMC have a protective effect against leakage of FITC-dextran in the cheek pouch after administration of various permeability-increasing substances, which further supports data previously reported on patients with venous insufficiency.