Dose-dependency Of Bothrops jararacussu  Crude Venom On Tibialis anteriorMuscle Response In Rats

Almeida-Silva, RD¹; Leite, GB¹; Rodrigues-Simioni, LR¹; Cruz-Höfling, MA²

1 Dept of Pharmacology, 2 Dept. of Histology and Embryology, IB, UNICAMP - Campinas, SP, Brazil.

Snakebite envenomation is a common condition in tropical countries. Bothropsjararacussu (Bjssu) is a large snake found in southern Brazil, responsible for 90.5% of snake Bothrops genus accidents. The gravity of muscle damage caused by Bjssu  accidents has led to investigate this biological phenomenon that rapidly develops.  The present work mimetizes a Bjssu accident using an in vivo experimental model aimed to correlate the concentration of the venom with contractile response and the extent of myonecrosis. The tibialis anterior muscle of adult anesthetized Wistar rats were prepared for myographic records. After stabilization the muscle was injected in the medium third with (Bjssu) (20, 60 or 180 g/0.02 ml) or sterile saline (control) and the effect observed during 120 min. After myographic recording the muscles were rinsed and fixed with Formol’s fixative for histopatological studies. The results revealed a direct progressive decrease in the twitch-tension amplitude, as well as in the percentage of damaged muscle area (23.7 ± 1.3, 44.2 ± 5.7 and 68.4 ± 4.9 %) according the increase of venom concentration compared with the control (2.5 ± 1.3%) (p<0.05). The maximum neuromuscular blockade was obtained up to 60 min, after which it was maintained stable until the end of the120 min. The myotoxic and neurotoxic effects in vivo preparation is dose-dependent and less sensitive to venom action than reported elsewhere for in vitro preparation.

Support: CAPES, CNPq, FAEP, FAPESP.

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