Intradermal injection of Bothrops cotiara venom in mice in an experimental wound model

Bothropic envenomation induces hemorrhage, coagulant disturbances and necrosis. Regarding therapies against the local damage caused by the venom, there is little information on tissue changes until the complete healing. In the current study, local damage was evaluated by examination of morphological inflammatory alterations, mast cell count, and analysis of collagen deposition. Bleeding was evident four hours after inoculation. After 24 hours, a large area of injury appeared presenting disorganized tissue, significant hemorrhage and acute inflammation. After three days, the damaged area was extensive, with a large amount of inflammatory cells and the presence of scab. In seven days, healing and reepithelization process started. And, 21 days later, the epithelium showed less infiltration and no skin appendages. The number of mast cells was similar to control after four hours, with a drop of 50 percent at 24 hours, followed by an increase until the 21st day. No differences of collagen deposition were observed among experimental groups. Taken together, wound healing after intradermal injection of Bothrops cotiara venom in mice follows similar parameters to wounds caused by other bothropic venoms. The present work reveals the importance of experimental wound models to the study of neutralizing agents against venom toxins.

A C-type lectin from Bothrops jararacussu venom can adhere to extracellular matrix proteins and induce the rolling of leukocytes

Purification of a lectin from Bothrops jararacussu venom (BjcuL) was carried out using agarose-D-galactose affinity gel. MALDI-TOF gave a major signal at m/z 32028, suggesting the presence of a dimmer composed of two identical subunits. Divalent cations were required for the lectin activity, as complete absence of such ions reduced hemagglutination. BjcuL was more effective at neutral pH and showed total loss of activity at pH values below 4.0 and above 9.0. Its agglutinating activity remained stable at 25°C until 60min, but increased when at 35°C for at least 15min. Adhesion assays to extracellular matrix (ECM) glycoproteins showed that the biotinylated lectin (0.039-5.0µg/100µl) was capable of binding to fibronectin and vitronectin in a dose-dependent manner. The binding was partially inhibited in the presence of D-galactose. BjcuL (1.25-10µg/30µl) potential was investigated for leukocyte rolling and adhesion to endothelial cells in living microvessels using intravital microscopy, which showed that it induced a dose-dependent increase in rolling and adherence of leukocytes, acting directly on endothelial cells of postcapillary venules. The specific association between lectins and their ligands, either on the cell surface or on the ECM, is related to a variety of biological processes. The complementary characterization of BjcuL, shown here, is useful to further understand the venom effects and as a background for future investigation for therapeutic strategies.