The acute inflammatory response induced in mice by the venom of the giant ant Dinoponera quadriceps involves macrophage and interleukin-1ß.

Dinoponera quadriceps (Hymenoptera, Formicidae, Ponerinae) is a primitive and endemic ant of Northeastern Brazil, that uses its sting and associated venom gland to capture preys and for defense. Venom of Dinoponera is of potential clinical importance, since it causes intense local pain, accompanied by erythema and edema, when injected by the sting. With other hymenopteran venoms, inflammatory effects are also reported. The aim of this study was to evaluate the inflammatory activity of D. quadriceps venom (DqV) in mice. Acrylamide electrophoresis of DqV revealed five main protein bands varying between 15 and 100 kDa, confirming the proteinous nature of DqV. DqV subplantar injection elicited edema at 5 µg/kg (3 fold), 50 µg/kg (4 fold) or 500 µg/kg (7 fold) from zero to 360 min compared to saline. DqV (50 µg/kg) increased vascular permeability (4 fold) in the first hour after induction. The paw tissue histology showed moderate inflammatory focus caused by DqV (50 µg/kg) in the first hour of paw edema, but severe tissue changes (edema, inflammatory infiltrate and focal areas of hemorrhage) in the third hour. Intraperitoneal injection of DqV (50 µg/kg) stimulated neutrophil (7 fold) and mononuclear (1.4 fold) migration vs saline. DqV edematogenic effect was inhibited by dexamethasone (92%), thalidomide (82%), cyproheptadine (62%), AA861 (58%), celecoxib (34%) or l-NAME (34%), but the neutrophil migration was only by dexamethasone (57%). DqV-elicited neutrophil migration at 50 µg/kg was potentiated 1.7 fold by the animals pre-treatment with 3% thioglycolate. DqV injection increased the levels of interleukin-1 beta (IL-1ß) in peritoneal cavities. DqV (50, 100 and 200 µg/mL) increased phospholipase activity (A425nm) from 10 min to 40 min. Raw 267 macrophages incubated with DqV (from 3.12 to 50 mg/mL) showed no significant decrease in cell viability or LDH measurements and at 35 µg/mL induced increase in IL-1ß (from 3 to 6 h). This study demonstrated, in mice, the inflammatory effect of D. quadriceps venom, characterized by edema, increase in vascular permeability and neutrophil migration, implying the participation of resident macrophages and IL-1ß, among other inflammatory mediators.

Venom's antinociceptive property in the primitive ant Dinoponera quadriceps.

ETHNOPHARMACOLOGICAL RELEVANCE: In northeastern Brazil, Dinoponera (Ponerinae) ants macerate are used to treat ear ache and its sting, rheumatism, and back pain. Such a popular use is a relevant fact that called for experimental evaluation of the antinociceptive activity of Dinoponera venom. MATERIALS AND METHODS: Dinoponera quadriceps venom (DqV; 5-500 µg/kg; i.v.) or morphine (3.4 mg/kg; s.c.) were evaluated in mice models of nociception (n=8 animals/group). Negative controls received sterile saline (0.9% NaCl; i.v.). RESULTS: DqV showed 64% protein content and exhibited antinociceptive activity, without affecting motor function, in the tests: formalin (72%), writhing (52%), von Frey (71%) and hot plate (45%). The antinociceptive activity was abolished under protein denaturant conditions. CONCLUSIONS: This study provided the first demonstration of the antinociceptive property of Dinoponera quadriceps venom in mice models of chemical, mechanical and thermal nociception, corroborating the popular use and suggesting its potential therapeutic utilization in painful conditions.