Poster 052 - Ontogenetic venom variation from freshwater stingray Potamotrygon scobina adults

Poster 52. 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.411.

Ontogenetic Venom Variation From Freshwater Stingray Potamotrygonscobina Adults And Embryos: Enzymatic And Biological Characterization.

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

1 Laboratório de Imunopatologia, Instituto Butantan, São Paulo; 2 Universidade Federal da Paraíba (UFPB), Paraíba; 3 Museu Paraense Emílio Goeldi (MPEG), Pará, Departamento de Dermatologia, Faculdade de Medicina, UNESP, Botucatu.

Potamotrygonscobina is a freshwater stingray (elasmobranch) distributed in the mid-low Amazon River drainage. These animals have a venomous glandular tissue that covers the bilateral retroserrated spine(s), which is located on their tails. The clinical signs and symptoms presented by patients accidentally wounded by their spines include severe pain and frequent cutaneous necrosis. The objective of this work was to compare the ontogenetic venom variation between adults and embryos. Adults venom was obtained from a pool of 11 stings from which the epithelium was carefully removed and dissolved in PBS (pH 7.4). The same process was repeated with 2 stings of a pregnant female and 4 stings of embryos aborted from this same specimen. Several embryos observed already presented the defense reaction (stinging) before dorsal pigmentation was completed. These freshwater stingrays are viviparous and give birth to active neonates. Analysis by SDS-PAGE 12.5% showed a similar electrophoretic profile among adult, female and embryos venom, presenting a major band of approximately 12 kDa. It was not detected private components, only differences of intensity in some bands located mainly around 12 and 41 kDa. All venom samples presented a very similar gelatinolytic, caseinolytic, and fibirinogenolytic activities, distributed between 89 and 210 kDa region. These enzymatic activities were not caused by metalloproteinases since most components still kept the ability to degradate all substrates after incubation with 1,10 phenanthroline. Hyaluronidase activity was not detected in the venom samples. Embryos venoms presented a similar edematogenic and nociceptive activity in mice when compared with adult and pregnant female venom samples. The results demonstrated great similarities among adult and embryo freshwater stingray venom. It could be suggested that freshwater stingray embryos have a venom apparatus ready before birth with a very similar composition to adult venom.