Male Swiss mice weighing 18–22 g were used. The animals were maintained for 2 days at the laboratory before experiments with water and food ad libitum in appropriate environmental conditions and were used under ethical conditions. All experimental procedures followed the ethical parameters proposed by the International Society of Toxinology and the Brazilian College of Experimental Animals and were approved by Ethical Committee for Use of Animals of Butantan Institute (protocol n° 591/09). A pool of lyophilized venom,

obtained from various adult specimens of HDAC inhibitor C. durissus terrificus snakes, was supplied by the Laboratory of Herpetology, Butantan Institute. The venom was stored at −20 °C and solutions (w/v) were prepared in sterile saline immediately before use. The crude venom was fractionated in a Mono-Q HR 5/5 column in a FPLC system (Pharmacia, Uppsala, Sweden) as previously described by Rangel-Santos et al. (2004). Three fractions (frI, frII and frIII) were obtained, and frII corresponded to pure crotoxin. The homogeneity of this toxin was checked by non-reducing sodium dodecyl sulfate–polyacrylamide gel electrophoresis (12.5%) (Laemmli, 1970). Crotoxin was also tested for lethality and phospholipase A2 activity (Santoro et al., 1999). The Cdt fractions used throughout this selleckchem study were generously supplied by Dr. Maisa Spendore Della Casa (Laboratory of Immunopathology, Butantan Institute). The BCG used as a phlogistic agent was prepared

with live attenuated bacilli of Mycobacterium bovis (Moreau strain), supplied in lyophilized form by Instituto Butantan. A suspension containing 8 × 105 bacilli in 30 μL of saline solution were injected into the footpad of mice. The contralateral paw received the same volume of saline solution. The concentration of BCG used in this study was based on data from the literature ( Moura and Mariano, 1996). Paw edema was evaluated once a day with the aid of a micrometer (Mitutoyo, Japan), for the 15 days after the BCG injection. In some experiments, edema was evaluated 1, 2, 4 and 6 h after the BCG injection. Results were calculated

as the difference mafosfamide in thickness of both BCG- and saline-injected paws, and edema was expressed as the percentage increase in paw thickness. To identify the inhibitory effect of the C. durissus terrificus venom on chronic paw edema induced by BCG, mice were injected with a single dose (75 μg/kg) of Cdt crude venom subcutaneously (s.c.) in the back 1 h before receiving BCG into the footpad. The paw edema was compared to that obtained in control animals injected with the saline solution (100 μL) instead of the Cdt venom, by the same route (s.c.). To determine if Cdt venom has an inhibitory effect after the initiation of a chronic inflammatory process, mice received an injection of BCG in the footpad. Groups then received Cdt venom in the back (s.c.) 1 h, 6 days or 11 days after the inoculation of BCG. The respective control groups received saline instead of venom.