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

Objective: 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.

Methods: 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.

Results: 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.

Conclusions: 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.