Potentiation of Carrageenan-Induced Rat Paw Edema by Natural Honey: Possible Role of Nitric Oxide and its Clinical Implication

Abstract

The effect of subplanter injection of honey alone or in combination with carrageenan in the rat paw was investigated. Paw volume was measured at different time intervals (0.5, 1, 2, 3 or 6 h) by using a plethysmometer. Injection of 0.1 ml of (10 or 20%) honey dose-dependently caused edema formation and maximum effects were observed at 1 h after injection. Similarly, injection of 0.1 ml of 1% carrageenan caused gradual increase in paw volume and maximum value was obtained at 6 h. Co-administration of either 10 or 20% honey with carrageenan resulted in significantly greater edema formation as compared to the values obtained with carrageenan alone for a period up to 2 h. Pre-treatment of rats with intraperitoneal injection of a nitric oxide synthase inhibitor, NG-nitro-L-arginine methyl ester (12.5 mg/kg) significantly reduced the paw edema that was obtained with honey alone or in combination with carrageenan for up to the period of 2 h only, whereas a dose of 6.25 mg/kg or enantiomer NG-nitro-D-arginine methyl ester (12.5 mg/kg) did not cause significant inhibition of edema formation. These results suggest that endogenous nitric oxide may be involved in the edematogenic response of honey. It is suggested that honey may activate nitric oxide system and this property of honey may be relevant for its effectiveness in healing of superficial open wounds.