As shown in Fig. 4A, all concentrations from 6.2 up to 100 μg/mL of BbV induced a significant release of IL-6 by human neutrophils compared to control. Fig. 4B shows that after 4 h incubation of neutrophils with concentrations from 12.5 up to 100 μg/mL

of BbV induced a significant release of IL-8 by human neutrophils. Our results demonstrate that BbV activated human neutrophils and induced the release of IL-6 and IL-8. In order to investigate the ability of BbV to induce the liberation of NETs by human neutrophils, the cells were incubated with non-cytotoxic concentrations of BbV or RPMI (control) or PMA (positive control). As shown in Fig. 5A and B, 4 and 15 h of incubation of human neutrophils Apoptosis inhibitor with different non-cytotoxic concentrations of BbV induced an increase in NETs liberation compared to the negative control (RPMI) and the positive control (PMA). These findings demonstrate the ability of BbV to stimulate human neutrophils to induce NETs liberation. The literature shows that leukocytes, and particularly neutrophils, play a critical role in skeletal muscle regeneration following myonecrosis induced by Bothrops asper venom

( Teixeira et al., 2003). In addition, CAL-101 in vivo a marked inflammatory cell response with a pronounced neutrophil infiltration associated with bothropic envenomation has been reported ( Gutiérrez et al., 1986, Flores et al., 1993, Farsky et al., 1997, Arruda et al., 2003, Zamunér Vorinostat et al., 2005 and Porto et al., 2007), but the state of activation of these cells is unknown. Besides this, it is quite possible that neutrophils – as the first cells at the site of an infection – might be able to clear a minor infection before monocytes even arrive. It therefore suggests the clearance of an infection by neutrophils without the classical symptoms of inflammation. Symptoms like

reddening, swelling, pain and potential tissue damage are all induced by pro-inflammatory cytokines that are secreted by the later arriving monocytes (Schröder et al., 2006). Taking this into account, we designed a study to investigate the ability of B. bilineata crude venom (BbV) to activate isolated human neutrophils since it has been shown that this venom causes inflammation and induces neutrophil recruitment into the peritoneal cavity of mice 4 h after its injection ( Porto et al., 2007). First, the effect of BbV on human neutrophil viability was evaluated. The results showed that BbV did not affect neutrophil viability indicating its low toxicity on this cell type. The effect of BbV on human neutrophil viability was not demonstrated until now, but literature shows that B. asper venom decreases the viability of neutrophils isolated from mice ( Moreira et al., 2009).