Perfis protéicos, enzimáticos e miotoxicidade induzidos pelos venenos das arraias amazônicas Plesiotrygon iwamae Rosa, Castello & Thorson, 1987 e Potamotrygon motoro Müller & Henle, 1841 (Chondrichthyes Potamotrygonidae)

Abstract

Accidents caused by freshwater stingrays are characterized by intense pain and pathological changes at the lesion site, which include edema, erythema and, in most cases, necrosis. In this study, mucus and tissue extracts from the dorsal region and sting of freshwater stingrays Potamotrygon motoro and Plesiotrygon iwamae were analyzed by electrophoresis on SDS-PAGE and zymography. The myotoxic activity (local and systemic) induced by extracts in murine model was evaluated by morphometric analysis and enzimatic activity of the phospholipase A2 (indirect hemolysis) in agarose gel. P. motorosting extract showed a diffuse band with 10 kDa, several between 58 and 27 kDa, and proteolytic components above 58 kDa, while the dorsal region extract showed a strong and diffuse band around 41 kDa and a proteolytic component with 6 kDa. P. iwamae showed, in all samples, a diffuse and intense band with 15 kDa and proteolytic components around 6 and 40 kDa. Doses of 140 μg of P. iwamae protein extracts (sting and dorsal region) induced indirect hemolysis after 24 and 48 hours, but the halo diameter was below 10 mm (minimum value set for the technical), showing a weak phospholipase A2activity. Coagulative necrosis of the muscle tissue, muscle fiber regeneration and inflammatory infiltrates, including neutrophils, macrophages and a reduced number of eosinophils and lymphocytes were observed 24 hours after injection of 400 μg of P. motoro and P. iwamae mucus extracts in mice gastrocnemius muscle. These results were also observed, in a lower proportion, in the gastrocnemius muscles of the contralateral legs, showing that extracts of both species were able to induce a systemic rhabdomyolysis when tested in BALB/c mice.