Pharmacological characterization of rat paw edema induced by Cerastes gasperettii (cerastes) Venom

Abstract

Inflammatory response induced by the venom of the Arabian sand viper Cerastes gasperettii was studied by measuring rat hind-paw edema. Cerastes gasperettii venom (CgV, 3.75-240 μg/paw), heated for 30s at 97°C, caused a marked dose and time-dependent edema in rat paw. Response was maximal 2h after venom administration and ceased within 24h. Heated CgV was routinely used in our experiments at the dose of 120 μg/paw. Among all the drugs and antivenoms tested, cyproheptadine and 5-nitroindazole were the most effective in inhibiting edema formation. Aprotinin, mepyramine, dexamethasone, diclofenac, dipyridamole, Nω-nitro-L-arginine, quinacrine, and nordihydroguaiaretic acid showed statistically (p<0.001) significant inhibitory effect, but with variations in their inhibition degree. Equine polyspecific and rabbit monospecific antivenoms significantly (p<0.001) reduced edema when locally administered (subplantar) but were ineffective when intravenously injected. We can conclude that the principal inflammatory mediators were serotonin, histamine, adenosine transport factors, phosphodiesterase (PDE), cyclooxygenase, lipoxygenase and phospholipase A 2 (PLA2), in addition to other prostaglandins and cytokines.