Stingray (Potamotrygon rex) maturity is associated with inflammatory capacity of the venom.

Several studies have been carried out with venom from sting and mucus of stingrays of marine or fluvial environments to compare the toxicity of their venom. However, studies demonstrating the existence of the influence of both sex and the maturation stage of stingrays on the variability of the toxic effects of venom are still scarce. Here, we investigated whether the sex and/or the stage maturation of the Potamotrygon rex stingray influence the toxic capacity of the venom to develop acute inflammation in mice. We carried out the main toxic activities in mice using venom from female or male of young and adult stingrays. Our results described here show that the nociception is mainly induced by venom from young female stingrays. In contrast, we observed the action of venom from both sex of adult stingrays in the induction of exudative phase of inflammatory process, including vascular leakage and neutrophil infiltration. Our data illustrate that the composition of the venom of P. rex is influenced by the stage of maturity of the stingray, modulating the production of peptides and proteins capable of acting on leukocytes-endothelial interactions and favoring neutrophil infiltration to the damage tissue.

Potamotrygon cf. henlei stingray mucus: biochemical features of a novel antimicrobial protein.

Antimicrobial molecules are important components of the innate immune system in vertebrates. They have been studied widely in several fishes, but little is known about these defence factors in stingrays, which are thought to have less sophisticated adaptive immune systems when compared to other teleosts. Stingrays from the specie Potamotrygon cf. henlei are distributed throughout the rivers of central-west Brazil, being the cause of numerous envenomations occurring in the dry seasons. In a previous study, we reported that the mucus of the stingray P. cf. henlei shows antimicrobial effects. Here, to analyze the antimicrobial compounds from the mucus of P. cf. henlei, we employed solid-phase extraction, chromatographic separation followed by ESI-MS, and Edman degradation. A protein similar to the ß-chain of hemoglobin was identified, isolated and partially sequenced by Edman degradation. This protein has a molecular weight of 16072.8 Da, and was shown to be active against bacteria (Micrococcus luteus and Escherichiacoli) and yeast (Candida tropicalis) without hemolytic activity. Effects of this new protein in the microcirculation environment were also evaluated. The results obtained provide fundamental information for future basic research, clinical diagnosis and development of new therapies to accident treatment. To the best of our knowledge, this is the first description of a bioactive polypeptide from the mucus of a stingray.

Studies on pharmacological properties of mucus and sting venom of Potamotrygon cf. henlei.

Stingrays from the Potamotrygon cf. henlei species are widely distributed in high numbers throughout the rivers of central-west Brazil, being the source of numerous envenomations occurring in the dry season, posing a serious public health problem even if not properly reported. The accidents usually involve fishermen and bathers, and to date there is no effective treatment for the injured. Considering these facts and limitations of studies aiming at understanding the effects induced by P. cf. henlei envenoming, this study aimed to describe the principal pharmacological and certain biochemical properties of the mucus and sting venom. We found that mucus and sting venom is toxic to mice having nociceptive, edematogenic and proteolysis activities. Our results also indicate that the inflammatory cellular influx observed could be triggered by the venom and mucus. Furthermore the venom and mucus were partially purified by solid-phase extraction tested for antimicrobial activity in which only the mucus presented activity. It could be inferred from the present study that P. cf. henlei venom possesses a diverse mixture of peptides, enzymes and pharmacologically active components.