Dual effects of a lectin from the green seaweed Caulerpa cupressoides var. lycopodium on inflammatory mediators in classical models of inflammation.

Wide biotechnological investigations of only a limited number of seaweed lectins have been performed. We previously demonstrated the anti-nociceptive and anti-inflammatory effects of a lectin isolated from the green seaweed Caulerpa cupressoides var. lycopodium (CcL). Herein, we further studied the mechanisms of action of CcL. Classical acute inflammation models induced by different flogistic agents were used to evaluate the anti-inflammatory action of CcL. CcL was injected locally into the rat paw to verify a possible pro-inflammatory outcome. CcL (0.1, 1 or 10 mg/kg; i.v.) reduced the carrageenan-induced rat paw edema and neutrophilic infiltration, which was not altered by either mucin (inhibitor of CcL carbohydrate-binding site) or ZnPP-IX (specific HO-1 inhibitor). Immunohistochemical analyses showed that CcL (1 mg/kg) reduced the expression of the cytokines IL-1β, TNF-α, IL-6 and COX-2. CcL (0.1, 1 or 10 mg/kg) inhibited dextran, and CcL (1 mg/kg) inhibited histamine-induced rat paw edema. Both effects were reversed by mucin inhibition. CcL (1 mg/kg) was ineffective for the treatment of serotonin- and bradykinin-induced rat paw edema. When injected via the i.pl. route, CcL (10 mg/kg) elicited rat paw edema involving a wide range of mediators. The anti-inflammatory action of CcL involves the inhibition of IL-1β, TNF-α, IL-6 and COX-2 expression and histamine H1 receptors. When locally administered, CcL exerts pro-inflammatory actions.