Antipermeability effects of Cyclo 3 Fort in hamsters with moderate diabetes

Ruscus aculeatus extract (the active principle of Cyclo 3 Fort) is used to increase venous tone in patients with venous disease. In these experiments, the effects of oral Cyclo 3 Fort on capillary permeability were studied in hamsters with moderate diabetes induced by two intraperitoneal injections of streptozotocin (40 mg/kg). Hamsters were treated with a placebo or Cyclo 3 Fort, 2, 10 or 50 mg/kg/day, for 4 weeks starting 3 days after induction of diabetes. Intravital microscopy of cheek pouch preparations was performed using fluorescein‐labelled dextran (FITC‐dextran) as a marker for plasma exudation (leak formation). Plasma levels of glucose were measured prior to experiments. Following preparation for intravital microscopy, each cheek pouch was subjected to two applications of histamine, $5\times10^{-6}$ M for 5 min at 30‐minute intervals. Plasma exudation (number of leaks/cm $^2$ ) was significantly reduced in animals receiving Cyclo 3 Fort at doses of 10 mg/kg or above. The mean number of leaks was $258\pm17$ in the placebo group, compared with $253\pm12$ , $125\pm7$ ( $p<0.01$ ) and $99\pm7$ ( $p<0.01$ ) in animals receiving Cyclo 3 Fort, 2, 10 or 50 mg/kg, respectively. Blood glucose levels did not differ between groups. Thus, oral Cyclo 3 Fort inhibited histamine‐induced plasma exudation in hamsters with mild diabetes without affecting the glycaemia.