Local alterations induced by the toxic secretion of Philodryas patagoniensis (Serpentes: Colubridae) / Alterações locais induzidas pela secreção tóxicas de Philodryas patagoniensis (Girard, 1857) (Serpentes: Colubridae)

AUTOR(ES)
DATA DE PUBLICAÇÃO

2008

RESUMO

The venom of Philodryas patagoniensis causes important and similar local lesions the ones that happen in the botropic accidents. The mechanisms involved in the local actions of this venom are little known. This study has as objective investigates the morphologic and inflammatory local actions of the venom of Philodryas patagoniensis and the mechanisms involved in the development of the pain and edema, through pharmacological modulation. The protein content of the venom was of 70-75%. The eletrophoretic analysis (SDS-PAGE 7,5-17,5%) it presented bands of protein with molecular weights between 62 and 14 kDa, being four majority in 62, 48, 35 and 30 kDa. The edema measured by pletismography, it was maximum 30 min after the inoculation (53,33 ± 1,43%), regressing starting from at 6th hour, it was shown dose-dependent, the edematogenic minimum dose was of 0,82µg and it was inhibited in 45% by EDTA. The nociceptive activity was evaluated by the time (in seconds) in that the animals licked or they bit the injected paw, and the results showed that such activity is dose-dependent, being significantly different from the control and independent of metaloproteinases, once it was not inhibited by EDTA. Through the pharmacological modulation it was possible to observe that the pain caused by the venom was inhibited by Indometacin, Cyproheptadine and Tramal, being mediated by opioids, prostaglandins and serotonin. It was potentiated by Captopril, suggesting the possible participation of kinins, as well as for L-NAME (10mg/kg). Dexamethasone, Prometazine, Arcoxia, Celebra and L-NAME (50mg/kg) didnt interfere in this activity. The edema was inhibited by Dexamethasone and Indometacin and, therefore, mediated for prostaglandins and leukotrienos. Captopril, Tramal, Prometazine, L-NAME, Arcoxia and Celebra were not capable to interfere significantly in the edema. The intramuscular injection of 30µg of the venom produced effects as disorganization of the muscular fibrils, hemorrhage, edema, inflammatory infiltrated and mionecrosis of the coagulative and miolitic types, which were inhibited in the presence of PMSF and 1-10Phenantrolina. Three, six and 24 hours after the intra-muscular inoculation of 60µg of venom, happened a gradual decrease of proteins no-colagen with light reduction in some miofibrilar components observed by SDS-PAGE (17,5%). The inflammatory infiltrated induced in cavity peritoneal was maximum three hours after the injection and the differential cellular counting presented polimorfonuclear leukocytes predominantly. The technique of intravital microscopy direct demonstrated that the topical administration of venom 0,1µg induced outstanding disturbances in post-capillary venules, characterized by vasodilatation, hemorrhagic lesions distributed in focuses (microbleedings) and alterations in the interactions leukocyte-endothelium, such as reduction of the number of leukocytes in rolling, increase of the adhesion and induction of the migration of cells through the wall of the endothelium. The subcutaneous inoculation of the venom in the scrotal bag of mice induced typical effects of sharp inflammation, with migrated leukocytes seen starting from one hour after the inoculation, regressing in 48 hours. The venom acts on mast cells in vitro, causing degranulating and consequent liberation of histamine concentration-dependent. The results obtained indicate the inflammatory potential of this venom and the kinetics of the events suggests a complex synergy of several effects, contributing to the severity of the local picture in the envenomings.

ASSUNTO(S)

serpentes venenos venoms venenos de origem animal venoms of animal origin snakes

ACESSO AO ARTIGO

Documentos Relacionados