Poster 061 - Enzymatic and biological characterization of the freshwater stingray Potamotrygon

Poster 61. Congresso da Sociedade Brasileira de Toxinologia, 8., Symposium of the Pan American Section of the International Society on Toxinology, 8., 2004, Angra dos Reis, Brasil. Abstracts... J. Venom. Anim. Toxins incl.Trop. Dis., 2004, 10, 3, p.420.

Enzymatic And Biological Characterization Of The Freshwater Stingray Potamotrygon scobina

¹Soares, S.L.; ¹Oliveira,T.A.; ²Charvet-Almeida, P.; ³Almeida, M. P.; ⁴Haddad Jr, V. and ¹Barbaro, K.C.

1 Laboratory of Immunopathology, Butantan Institute, São Paulo, 2 Universidade Federal da Paraíba (UFPB), Paraíba; 3 Museu Paraense Emílio Goeldi (MPEG), Pará; 4 Departament of Dermatology, School of Medicine, UNESP, Botucatu, Brazil;

Freshwater stingrays are cartilagenous fishes very common in some Northern and Middle-Western rivers in Brazil. They have one or more retrosserated stings on the tail covered by integumentary and glandular tissues where the venom is produced. The injuries occur when humans accidentally step on these stingrays. Pain is the main symptom followed by local edema and erythema. In later phases, skin necrosis and ulcers can be present. The aim of this work was to characterize some aspects of the Potamotrygon scobina venom. The specimens were collected near Colares Island (Pará State, Brazil). The sting epithelium containing the venom was removed and diluted in a PBS solution. The SDS-PAGE analysis showed a major component with approximately 12 kDa. At least 16 bands are distributed between 18.8 and 89 kDa regions. Many components with molecular weight above 83 kDa presented gelatinolytic, caseinolytic and fibrinogenolytic activities with similar profiles among them. These enzymatic activities were not caused by metalloproteinases since most components kept the ability to degradate all substrate after incubation with 1,10 phenanthroline. The venom present dose-dependent response in edematogenic and nociceptive activities. Edema was observed with a peak activity at 15 minutes after injection. To verify the termolability of the venom, samples were heated at 37°C and 56°C for 30 minutes or left during 24 hours at room temperature and enzymatic and biological activities were studied. Only at 56°C it was possible to verify the suppression of the enzymatic activity. The nociceptive and edematogenic activities decreased after venom incubation at 56°C. The results demonstrated that the venom is termolable and the local effects observed in humans may be caused, in part, by its enzymatic activities. After incubation at 56°C, enzymatic and toxic activities decreased, indicating a possible use of heat to minimize the symptomatology caused by the venom.