PHOSPHOLIPASE A₂, PROCOAGULANT AND FIBRINOLYTIC ACTIVITIES FROM Lonomia obliqua VENOM

Veiga, A.B G.;Pinto, A.F.M.; Dobrovolski, R.; Guimarães, J. A.

Laboratório de Bioquímica Farmacológica, Centro de Biotecnologia, UFRGS

Introduction: Venom from Lonomia obliqua caterpillar is responsible for a haemorrhagic disorder reported in Southern Brazil. The clinical profile – characterized by haematuria, severe bleeding, acute renal failure and even death of untreated patients – probably results from the action of several and distinct active principles, present in different caterpillar secretions that enter the blood system during accidental contact.

Objectives: In this work we analysephospholipaseA₂, procoagulant and fibrinolytic activities in different materials from L. obliqua: secretion obtained by thermal (-20 ºC) stress, tegumental extract, spicule extract and haemolymph.

Materials:The materials were assayed in order to: a) indicate phospholipase A₂ activity by indirect haemolysis of rabbit erythrocytes using egg yolk as substrate, b) analyse procoagulant activity upon recalcification time of human plasma in an ELISA-like system monitored by SpectraMax, c) analyse fibrinolytic activity by SDS-PAGE.

Results: Procoagulant activity was found in all the samples: spicule extract (45.0 U/mg), secretion obtained by thermal stress (11.5 U/mg), tegumental extract (11.0 U/mg), haemolymph (6.0 U/mg). Fibrinolytic activity was observed after 24h of incubation in the haemolymph, in the tegumental extract and in the secretion obtained by thermal stress, the latter being the highest one, even after 10min of incubation. Phospholipase A₂ activity was only found in the spicule extract (80.0 U/mg).

Conclusion: The activities studied in this work are not homogenously distributed throughout the caterpillar´s body. Results strongly indicate that the haemorrhage observed in this envenomation seems to be due to the combination of these activities.

Supported by: CAPES and FAPERGS.

CORRESPONDENCE TO:

Ana Beatriz Gorini da Veiga, Avenida Érico Veríssimo, 441/615, Porto Alegre, RS, CEP: 90160-181, Brasil, Email: anabgv@dna.cbiot.ufrgs.br