Antagonistic action of marimastat, a metalloprotease synthetic peptide inhibitor, on the myotoxic, hemorrhagic and coagulant effects of Lachesis muta muta (South American Bushmaster) venom in rodents

Abstract

Envenomation by Lachesis is characterized by clinical manifestations such as local and systemic myonecrosis, renal dysfunction, hemorrhage, coagulopathy, and hypotension. The treatment for envenomation by Lachesis is conditioned to serotherapy and there are few reports related to application of other therapeutics pathways. Recent studies have shown that marimastat, a metalloprotease synthetic peptide inhibitor, can be used as a potential coadjutant agent to serotherapy in envenomation by Viperidae and Elapidae snakes. In this project, we aim to assess the protective action of marimastat, associated or not to polyvalent anti-Bothrops/Lachesis serum, on the myotonic, hemorrhagic, and coagulant action of the Lachesis muta muta (Sul-American Bushmaster) in animal experimentation models in vitro and in vivo. Initially, we will carry out an enzymatic kinetic protocol for caseinolytic and esterase activities to determine the minimum inhibitory concentration of marimastat on the major proteases of this venom; it will be applied colorimetric methods, with the reactions being read in a spectrophotometer. For in vitro protocols, the inhibitory action of marimastat (alone or associated with antivenom) on the hemostatic activity of the L. m. muta venom will be determined from the minimal coagulant dose, activation of prothrombin and activated partial thromboplastin, and thrombin-like activity in rat citrated plasma using commercial kits for coagulometry. In addition, the inhibitory action of the drug alone or associated with antivenom will be assessed on the myotoxicity of the L. m. muta venom in mouse isolated nerve phrenic diaphragm preparation mounted in a multifunction myographic system. In vivo, the inhibitory action of both agents on the haemorrhagic effect of L. m. muta venom will be assess through formation of subcutaneous hemorrhagic halo in rats. The results of this study will contribute to understand the therapeutic potential of marimastat on the effects induced by Lachesis venoms.