In Vitro Study of Nitric Oxide Metabolites Effects on Human Hydatid of Echinococcus granulosus

Hydatidosis is characterized by the long-term coexistence of larva Echinococcus granulosus and its host without effective rejection. Previous studies demonstrated nitric oxide (NO) production (in vivo and in vitro) during hydatidosis. In this study, we investigated the direct in vitro effects of NO species: nitrite (NO(2) (-)), nitrate (NO(3) (-)) and peroxynitrite (ONOO(-)) on protoscolices (PSCs) viability and hydatid cyst layers integrity for 24 hours and 48 hours. Our results showed protoscolicidal activity of NO(2) (-) and ONOO(-) 24 hours and 3 hours after treatment with 320 muM and 80 muM respectively. Degenerative effects were observed on germinal and laminated layers. The comparison of the in vitro effects of NO species on the PSCs viability indicated that ONOO(-) is more cytotoxic than NO(2) (-). In contrast, NO(3) (-) has no effect. These results suggest possible involvement of NO(2) (-) and ONOO(-) in antihydatic action and point the efficacy of these metabolites as scolicidal agents.