Venom of the giant ant Dinoponera quadriceps attenuates inflammatory pain in mouse cutaneous wound healing model

Arthropod venoms are potential sources of bioactive substances, providing tools for the validation of popular use and new drugs design. Ants belonging to the genus Dinoponera are used in the folk medicine to treat inflammatory conditions. It was previously demonstrated that the venom of the giant ant Dinoponera quadriceps (DqV), containing a mixture of polypeptides, elicit antinociceptive effect in mice models of chemical, mechanical and thermal nociception. The aim of this study was to evaluate DqV antiinflammatory and antihypernociceptive effects in a mice model of traumatic cutaneous wound. Colonies of D. quadriceps were collected in the ‘‘Serra de Maranguape’’ (State of Ceará, northeastern Brazil), a small mountain range located on the coastal zone, and the venom secreted by the ant glands was extracted with capillary tubes, further lyophilized and maintained at -20 ± 1ºC until use. Wounds were performed in the dorsum of Swiss mice. Animals received intravenous (i.v.) injection of DqV (50 µg -1kg day-1) during 3 days for evaluation of inflammatory parameters present in the wounds: hypernociception, leukocyte infiltrate, myeloperoxidase activity, nitrite nitrate-1 content. Data was tested by two-way ANOVA and Bonferroni’s post-hoc test. DqV reduced (2.7 folds) hypernociception at 48 hours, leukocyte infiltration by 65% at 6 hours and myeloperoxidase activity by 60% at 0.5 hour after wound induction. In conclusion, the venom extracted from D. quadriceps glands attenuates inflammation and hypernociception in mice cutaneous wounds.

The lectin isolated from Lonchocarpus araripensis seed elicits endothelium-dependent vasorelaxation / A lectina isolada de sementes de Lonchocarpus araripensis promove efeito vasorelaxante dependente de endotélio

Background: The vasorelaxant effect of lectins from leguminous plants (Diocleinae subtribe) is well described. However, this effect has been little explored for lectins isolated from Dalbergieae tribe, except for that of Vatairea guianensis, that induces vasorelaxation involving nitric oxide and the lectin domain. Objective: To evaluate the vasorelaxant effect of a lectin isolated from Lonchocarpus araripensis (LAL), Dalbergieae tribe, and the involvement of the lectin domain and endothelium derived relaxing factors. Methods: Aortic rings of Wistar rats (250 - 300 g) were mounted in organ bath and mantained in physiological conditions (CEUA No. 10130208-8/40). LAL (0.1­100 µg/ml) was added to phenylephrine (0.1 µM)-contracted tissues with either endothelium intact or denuded. In order to investigate the mechanisms of LAL relaxation, inhibitors of NOS (L-NAME: 100 µM), cyclooxygenase (indomethacin: 10 µM), or potassium channels (TEA: 5 mM) were added to endothelized tissues 30 min before contraction. The involvement of lectin domain was assessed by previous incubation of LAL (30 µg/ml) with GlcNAc (0.1 M). Results: LAL (0.1-100 µg/ml) induced relaxation only in endothelized aorta, being maximal at 100 µg/ml (62.57 ± 7.8%). The relaxant effect induced by LAL at 30 µg/ml (52.49 ± 10.32%) was abolished by previous incubation with GlcNAc. LAL relaxant effect (IC50 9.75 ± 7.1) was partially reversed by indomethacin (IC50 LAL + indomethacin: 30.47 ± 10.93) and was abolished by L-NAME or TEA. Conclusion: LAL exhibits vasorelaxant activity in contracted endothelized aorta of rats, involving the lectin domain, muscarinic receptor of acetylcholine and endothelial derived relaxing factors. (AU)

Introdução: O efeito vasorrelaxante de lectinas de plantas leguminosas (Subtribo Diocleinae) já é bem descrito, embora pouco explorado para lectinas isoladas da tribo Dalbergieae, com exceção da lectina de Vatairea guianensis, que induz relaxamento com envolvimento de óxido nítrico e do domínio lectínico. Objetivo: Avaliar o efeito vasorrelaxante da lectina isolada de Lonchocarpus araripensis (LAL), tribo Dalbergieae, e o envolvimento do domínio lectínico e de fatores relaxantes derivados do endotélio (EDRF). Métodos: Anéis de aorta de ratos Wistar (250-300 g) foram montados em banho de órgãos em condições fisiológicas (Tyrode, 37 ° C, 95% de O2 e 5% de CO2, pH = 7,4) (CEUA No. 10130208-8/40). LAL (0,1-100 µg/ml) foi adicionada a tecidos pré-contraídos com fenilefrina (0,1 µM) com ou sem endotélio. Para investigar os mecanismos de relaxamento, foram adicionados inibidores de NOS (L-NAME: 100 µM), guanilato ciclase (ODQ: 10 µM), receptor muscarínico (atropina: 1 µM), ciclooxigenase (indometacina: 10 µM) ou canais de potássio (TEA: 5 mM) aos tecidos endotelizados 30 minutos antes da contração. O envolvimento do domínio lectínico foi avaliado por incubação prévia da LAL (30 µg/ml) com GlcNAc (0,1 M). Resultados: LAL (0,1-100 µg/ml) relaxou apenas anéis de aorta endotelizadas, com efeito máximo na dose de 100 µg/ml (62,57 ± 7,8%). O efeito relaxante da LAL a 30 µg/ml (52,49 ± 10,32%) foi abolido por incubação prévia com GlcNAc, atropina ou ODQ. O relaxamento da LAL (IC50 9,75 ± 7,1) a 10, 30 e 100 µg/ml foi parcialmente revertido por indometacina (IC50 LAL + indometacina: 30,47 ± 10,93) e abolido por L-NAME e TEA. Conclusão: A LAL exibe atividade vasorrelaxante em aorta endotelizada de ratos, no estado contraído, envolvendo o domínio lectínico, receptor muscarínico e fatores relaxantes derivados do endotélio. (AU)