Untitled

Abstract

Envenomations caused by different species of Bothrops snakes result in severe local tissue damage, hemorrhage, pain, myonecrosis, and inflammation with a significant leukocyte accumulation at the bite site. However, the activation state of leukocytes is still unclear. According to clinical cases and experimental work, the local effects observed in envenenomation by Bothrops alternatus are mainly the appearance of edema, hemorrhage, and necrosis. In this study we investigated the ability of Bothrops alternatus crude venom to induce macrophage activation. At 6 to 100 μg/mL, BaV is not toxic to thioglycollate-elicited macrophages; at 3 and 6 μg/mL, it did not interfere in macrophage adhesion or detachment. Moreover, at concentrations of 1.5, 3, and 6 μg/mL the venom induced an increase in phagocytosis via complement receptor one hour after incubation. Pharmacological treatment of thioglycollate-elicited macrophages with staurosporine, a protein kinase (PKC) inhibitor, abolished phagocytosis, suggesting that PKC may be involved in the increase of serum-opsonized zymosan phagocytosis induced by BaV. Moreover, BaV also induced the production of anion superoxide (O 2-) by thioglycollate-elicited macrophages. This BaV stimulated superoxide production was abolished after treating the cells with staurosporine, indicating that PKC is an important signaling pathway for the production of this radical. Based on these results, we suggest that phagocytosis and reactive oxygen species are involved in the pathogenesis of local tissue damage characteristic of Bothrops spp. envenomations.

Inflammation Induced by Platelet-Activating Viperid Snake Venoms: Perspectives on Thromboinflammation

“…Studies have showed generation of reactive oxygen species (ROS) by macrophages and peritoneal leukocytes stimulated with Bothrops sp. snake venoms (97, 102). Further, increased production of hydrogen peroxide and nitric oxide by macrophages followed by generation of peroxynitrites induced by Bothrops snake venoms (103) and the ability of Vipera russelli , a snake of medical importance in Asia, to activate production of ROS in neutrophils were also described.…”

Immunological Responses to Envenomation

“…Again, BAV-treatment showed a limited impact on MF viability, as evaluated by Trypan blue exclusion, and did not interfere with MF's adhesion or detachment capacity up to 100 µg/mL BAV (49). Pretreatment with the protein kinase C inhibitor, staurosporine (14 nM/mL), suppressed O − 2 production and phagocytosis, suggesting the involvement of a PKC-dependent signalling pathway (49). However, unlike CDTV, Setubal et al observed increased MF complement receptor (CR3)-mediated phagocytosis following incubation with BAV (49).…”

“…2 ) from isolated thioglycollate-elicited MFs (49). Again, BAV-treatment showed a limited impact on MF viability, as evaluated by Trypan blue exclusion, and did not interfere with MF's adhesion or detachment capacity up to 100 µg/mL BAV (49).…”

“…2 ) from isolated thioglycollate-elicited MFs (49). Again, BAV-treatment showed a limited impact on MF viability, as evaluated by Trypan blue exclusion, and did not interfere with MF's adhesion or detachment capacity up to 100 µg/mL BAV (49). Pretreatment with the protein kinase C inhibitor, staurosporine (14 nM/mL), suppressed O − 2 production and phagocytosis, suggesting the involvement of a PKC-dependent signalling pathway (49).…”

“…Pretreatment with the protein kinase C inhibitor, staurosporine (14 nM/mL), suppressed O − 2 production and phagocytosis, suggesting the involvement of a PKC-dependent signalling pathway (49). However, unlike CDTV, Setubal et al observed increased MF complement receptor (CR3)-mediated phagocytosis following incubation with BAV (49). Phagocytosis of serum-opsonised zymosan particles was significantly higher in venom-stimulated MFs compared to vehicle control (49).…”