The inhibitory effect of saPLIγ, a snake sourced PLA 2 inhibitor on carrageenan-induced inflammation in mice

Abstract SaPLIγ is a natural phospholipase A 2 (PLA 2 ) inhibitor, isolated from Sinonatrix annularis, that has been demonstrated to protect against envenomation by other venomous snakes. As snake venom PLA 2 s and mammalian secretory PLA 2 s are similar, saPLIγ is thought to have potential to alleviate inflammatory reactions in which PLA 2 s act as a key enzyme for arachidonic acid release. The aim of this study was to investigate the anti-inflammatory effects and mechanisms of action of saPLIγ in an animal model of carrageenan-induced acute inflammation. The results indicated that saPLIγ inhibited PLA 2 subtypes extensively, especially IIA-PLA 2 , in a dose-dependent manner. Paw swelling in mice was reduced markedly by intraperitoneal saPLIγ 2 .5 mg/kg, and the effect was significantly better than observed with dexamethasone at the same dose. Lower neutrophil infiltration and tissue edema was observed in the paws of saPLIγ-treated mice. Additionally, carrageenan-induced cyclooxygenase- 2 (COX- 2 ) and pro-inflammatory cytokines (TNFα and IL-1β) were also significantly down-regulated by saPLIγ in a dose-dependent manner. These results suggested that saPLIγ had effective anti-inflammatory effects in vivo, and these were produced by blocking mammalian IB, IIA, V and X sPLA2 subtypes.