In this find more investigation we have tested the myotoxic and edematogenic effects of Bothrops jararaca and Bothrops jararacussu venom in mice under different in vitro and in vivo approaches, and the anti-inflammatory and antimyotoxic

effects of dexamethasone. Male Swiss mice (25.0 ± 1.0 g) used for the study received water and food ad libitum and were kept under a natural light cycle. Euthanasia and all the procedures that could cause pain were performed under diethyl-ether anesthesia according to protocols approved by the Ethics Committee for the Use of Animals of the Federal University of Rio de Janeiro (CEUA-UFRJ). B. jararaca and B. jararacussu venoms, and polyvalent antivenom (PAV)

serum were obtained from Instituto Vital Brasil, Rio de Janeiro, Brazil; dexamethasone was obtained from Hypofarma, Brazil; dry ethanolic extract of Eclipta prostrata was prepared as previously described ( Mors et al., 1989; Melo et al., 1994) and fresh solutions were made from the lyophilized plant prior to each experiment; creatine kinase (CK) activity was determined using a CK NAC® kit from BIOCLIN, Brazil; hexadecyltrimethylammonium bromide (HTAB) and O-dianisidine dihydrochloride were purchased from Sigma–Aldrich Co, USA. Perimuscular injections of B. jararaca

and B. jararacussu venoms (1.0 mg/kg), dissolved in PSS to final volume 50 μL, were performed in mice Protein Tyrosine Kinase inhibitor at their legs over the extensor digitorum longus (EDL) muscle, not directly into the muscle, but under the tibialis anterior muscle and next to the tibia, close to the external surface of EDL muscle, in order not to cause Liothyronine Sodium mechanical damage to this muscle, as previously described ( Melo and Ownby, 1999; Calil-Elias et al., 2002). Negative controls consisted of mice injected with the same volume of physiological saline solution (PSS) composed of (mM): NaCl, 135; KCl, 5; CaCl2, 2; MgCl2, 1; NaHPO4, 1; NaHCO3, 15; and dextrose, 11. The pH of this solution was equilibrated to 7.3 with 5% CO2/95% O2. Treatment groups consisted of: intraperitoneal dexamethasone (1.0 mg/kg) in a final volume of 100 μL, injected simultaneously with the venoms; E. prostrata (50.0 mg/kg) pre-incubated with the venom for 15 min ( Melo et al., 1994) prior to perimuscular injection; and the association of DEXA and EP protocols. We also used intravenous PAV (0.2 mL/mg of venom, once each milliliter of PAV is ascribed to neutralize 2.5–5.0 mg of the Bothrops crude venoms according to the producers’ recommendations) injected simultaneously with the venoms.