Effects of the Lonomia achelous Caterpillar Venom on TNFarelease and some Haemostatic Parameters in Mice

M. Barrios, A. Salazar, A. Gil, P. Taylor, C.L. Arocha-Piñango, B. Guerrero.

Instituto Venezolano de Investigaciones Científicas (IVIC). Centro de Medicina Experimental. Caracas, Venezuela.

Patients affected with the hemorrhagic syndrome induced by contact with the caterpillar Lonomia achelous have presented different systemic effects, such as: hemorrhage, coagulopathies, edema and renal failure. The pathogenesis of these effects are complex, involving both the direct action of venom components on the tissues and the release of various endogenous inflammatory mediators. As part of the characterization of the possible inflammatory response induced by the venom of L. achelous, their effects were studied on the TNFa release (proinflammatory cytokine) and some haemostatic parameters (fibrinogen, factor XIII, plasminogen and endogenous fibrinolytic activity) in a mouse model. Methodology. C57BL/6 mice were used throughout the study which were inoculated intradermically with 150 mL of crude venom, containing 1.6 mg of total proteins. Their effects were evaluated: 1) 24, 48, 96 and 120 hours after inoculation, on: a) the fibrinogen levels measured by gravimetric method, factor XIII using a micromethod with monodansilcadaverin/casein, and plasminogen with a commercial kit; b) the fibrinolytic activity of the euglobulin fraction using the fibrin plate method. 2) 0, 1, 2, 4, 6, 12 and 24 hours after inoculation, on the serum TNFa levels through a WEHI cytotoxicity assay. Results. We have observed: 1) a decrease time dependent of the fibrinogen and factor XIII levels, regarding the controls (p <0.01) and plasminogen, between 24 and 48 h (p <0.01) with a tendency to normalize after 96 h; 2) endogenous fibrinolytic activity detected  by lysis in fibrin plate, time dependent of inoculation with the euglobulin fraction obtained from experimental mice; 3) TNFa levels, measured in mice serum inoculated with the venom, showing a curve with a peak at about 1 h post-inoculation then decrease without reach basal values. Conclusion. The crude venom of Lonomia achelous induces the early TNFa release, that could partly explain the effects on the hemostatic system, since TNFa, has been associated with changes in some hemostatic parameters and with IL-6 release, who also affects the coagulation and fibrinolytic system.

Correspondence to: bguerrer@medicina.ivic.ve