Contribution OfComplement and NeutrophilsOn Inflammatory Process Induced By Bothrops atroxVenom.

Escocard, R.C.M.¹, Rodrigues, F.G.¹, Kanashiro, M.M.¹, Petretski, J.H.¹, Lemos, L.S.², Carvalho, E.Q², Dias da Silva, W.¹and Kipnis, T.L.¹

1 Laboratório de Biologia do Reconhecer. 2 Laboratório de Sanidade Animal. UENF. RJ - Brasil.

Bothropsatrox (Ba) venom injected in muscle induces strong inflammatory cell infiltration and severe hemorrhage. We investigated the role of the complement system (C), neutrophils and inflammatory mediators production in the inflammation and hemorrhage induced by Ba venom or by its purified components. Crude Ba venom injected ip into mice evokes intense cell migration characterized predominantly by neutrophils in the early stage. Increases in serum levels of IL-1b, IL-6, MIP-1b, MIP-2.

and NO, but not TNF-a, were detected along with the cell influx. In neutrophil (Ne)-depleted mice production of IL-6, MIP-1b, MIP-2 and NO was increased, while IL-1b was reduced. Ne-depleted mice demonstrated higher levels of CCR1, CCR5 and iNOS mRNA using peritoneal cells. When venom was injected into the muscle of depleted mice, neutrophils were practically absent but edema, hemorrhage and the Delta-lesions were still observed in the lesion. Local production of those mediators induced by PLA2 Asp-49 injected in the muscle showed that only IL-1 and IL-6 were expressed. The role of the C in the mechanisms of inflammation and hemorrhage induced by Ba venom was tested using groups of C sufficient or deficient mice. The participation of neutrophils in these processes was evaluated by histological analysis of the local lesions in groups of normal mice or C5-deficient mice. A purified hemorrhagin HI-5 (low molecular mass) exhibited proteolytic and C inactivating properties in vitro. HI-5 when injected im induced a Ba characteristic local inflammation. In contrast, when HI-5 was injected into mice that had been previously C depleted the number of neutrophils per tissue section, but no hemorrhage was significantly reduced. Similar results were obtained when C5-deficient A/J mice were used as substitutes for BALB/c C-sufficient mice. HIII-7 (a PIII class 55 kDa hemorrhagin) injected im in BALB/c normal mice induced neutrophil infiltration and production of inflammatory mediators in a similar manner to that of crude venom. Taken together, these data demonstrate that the C is involved in neutrophil accumulation, but not in hemorrhage at the local lesions induced by low molecular mass Ba hemorrhagin and that inflammatory mediators induced by the venom are modulated by neutrophils.

Support: FAPERJ, CNPq, UENF.

Correspondence to: kmilton@uenf.br