Bites caused by Scolopendra viridicornis centipede are mainly characterized by
burning pain,
paresthesia and
edema. On this regard, the aim of this work was to study the involvement of mast cells and
histamine in
edema induced by Scolopendra viridicornis (Sv) centipede
venom. The
edema was analyzed on mice paws. The mice were pretreated with
cromolyn (mast cell degranulation inhibitor) and antagonists of
histamine receptors, such as
promethazine (H1R),
cimetidine (H2R) and
thioperamide (H3/H4R). The analyses were carried out at different times after the injection of Sv
venom (15 μg) or PBS in the footpad of mice. Our results showed a significant inhibition of the
edema induced by Sv
venom injection in mice previously treated:
cromolyn (38-91%),
promethazine (50-59%) and
thioperamide (around 30%). The treatment with
cimetidine did not alter the
edema induced by Sv
venom. Histopathological analysis showed that Sv
venom injection (15 μg) induced
edema, leukocyte recruitment and mast cells degranulation, when compared with the PBS-injected mice. Direct effects of the Sv
venom on mast cells were studied in PT-18 line (mouse mast cell) and RBL-2H3 cells (rat mast cells). The data showed that higher doses (3.8 and 7.5 μg) of Sv
venom were cytotoxic for both cell lineages and induced morphological changes. However, lower doses of the
venom induced degranulation of both mast cell lines, as well as the secretion of MCP-1,
IL-6 and IL-1β. The production of
PGD2 was only observed in the RBL-2H3 line incubated with Sv
venom. Taking our results together, we demonstrated that upon Sv
venom exposure, mast cells and
histamine are crucial for the establishment of the local inflammatory reaction.