Antioxidant-Angioprotective Actions of Calcium Dobesilate in Diabetic Rats

Calcium dobesilate was tested in rats with streptozotocin(STZ)-induced diabetes, for its angioprotective properties against the extravasation of plasma Evans blue towards the peritoneal cavity, induced in situ by the free radical generating agent phenazine methosulfate (PMS). In diabetic rats pretreated with a single oral dose of 50 and 200 mg/kg calcium dobesilate, PMS-induced Evans blue extravasation was respectively reduced by 60 and 100% with respect to values in vehicle-treated animals (p < 0.05 and p < 0.01 respectively; in diabetic rats, PMS-induced Evans blue peritoneal extravasation was double as in control animals = 0.0814 +/- 0.019 vs. 0.0396 +/- 0.0083 h-1, p < 0.05). In diabetic rats pretreated with 50 and 100 mg/kg/day of calcium dobesilate for 7 days, PMS-induced Evans blue extravasation was respectively reduced by 56 and 80% with respect to values in vehicle-treated animals (p < 0.01 and p < 0.001 respectively). In conclusion, calcium dobesilate p.o. significantly and dose-dependently antagonized the increase in capillary permeability induced by an oxidative stress in the peritoneal cavity of diabetic rats. These results further suggest that the antioxidant properties of calcium dobesilate can be involved, at least in part, in its angioprotective actions in humans.