Anti‐oedematous Effect of Hidrosmin on Thermal Injury Oedema and Acute Lymphoedema in the Rat Hind Leg

Different flavonoid compounds can reduce high-protein oedemas. The aim of this study was to evaluate the effect of hidrosmin, a synthetic flavonoid, on thermal injury oedema and acute lymphoedema in the hind leg of rats. Immersion of the right hind leg, up to the knee joint, in a water bath at 55°C for 1 min induced oedematous swelling that increased the leg volume by 17.5 ± 1.5 and 26.6 ± 1.6% after 2 and 4h, respectively. Administration of hidrosmin (25, 50 and 100 mg kg−1, i.v.), 1 h before and 1 h after thermal injury, reduced oedema formation in a dose-dependent manner (at 4 h, r = 0.48, P < 0.001; ED50 = 57.7 mg kg−1). The potency of hidrosmin was similar to that found for troxerutin and coumarin. The combination of burning with ligature of the lymphatic vessels led to acute lymphoedema development that was reduced by intraperitoneal administration of hidrosmin (50 mg kg−1 every 12 h) by approximately —27, —34, and —57% at 24, 48 and 72 h after injury, respectively. These results show that hidrosmin treatment is effective in reducing both the oedematous swelling after thermal injury and the development of acute lymphoedema.