Local inflammatory mediators alterations induced by Daboia siamensis venom

The ability of Russell's viper (Daboia siamensis) venom (total RVV) and phospholipase A₂ (purified PLA₂) to induce the local pathological effects were investigated by the local inflammatory events and the release of inflammatory mediators. Both 0.5 μg of total RVV/mouse and 0.15 μg of purified PLA₂/mouse were administered via intra-peritoneal injection. After 30 min, 1 h, 2 h, and 4 h incubation time, the peritoneal cavity was flooded with normal saline and the total leukocytes were collected. The eicosanoids (lipid mediators) and the leukocyte expression of cyclooxygenase (COX-1 and COX-2) were investigated by ELISA assay and western blotting, respectively. The amounts of total leukocytes were increased from 30 min to 2 h, then decreased at 4 h, by both total RVV and purified PLA₂. Both treatments also induced the expression of COX-2 which was increased at 2 h and then decreased at 4 h, whereas only purified PLA₂ induced the expression level of a COX-1 protein which was increased at 30 min, then constantly expressed until 4 h. In addition, total RVV and purified PLA₂ caused the release of the eicosanoids; PGE₂, TXB₂, and LTB₄, which reached the peak after 2 h. The findings of this study indicate that purified PLA₂ has the potential effects to induce the local inflammation relating the amounts of leukocytes cells, lipid mediators and COX-2 more than the total RVV.