Abstract
The aim of the present study was the determination and comparison of lethal effects of Ag-NPs and Se-NPs on protoscolices of hydatid cyst. Livers and lungs of sheep, which was naturally infected by hydatid cyst were collected from Tabriz slaughterhouse and transferred to the parasitology laboratory. Initially, the surface of cysts was disinfected by 70% Alcohol. Then, 25 ml of each cyst fluid were aspirated by sterile syringe and transferred to Erlenmeyer flask. After 30 minutes, the supernatant was discarded and protoscolices were washed with phosphate-buffered saline and tested by 1% eosin to assess their viability. Next, the samples of protoscolices, which were over 90%, were selected and the effect of 50, 125, 250 and 500 (µg/ml) of Se-NPs and Ag-NPs in the exposure times of 10, 20, 30 and 60 min were evaluated. Data were analysed by SAS software and analyzed by Duncan's comparison test. The significant differences were considered to be p<0.0001.The difference between the scolicidal effects of Se-NPs was statistically significant for all examined concentrations and exposure times compared to the control group (p<0.0001). On the other hand, the scolicidal effect of Ag-NPs in 10 and 20 min exposer was not significant in comparison to the control group. Overall scolicidal effect of Se-NPs was higher than Ag-NPs and the difference was significant (p<0.0001).The results of the present research indicated that it is possible to use Se-NPs as an effective scolicidal treatment. It is suggested the study of employing this compound in vivo or in combination with other procedures in treating hydatid cyst in further studies.

Key words: Hydatid cyst; Ag-NPs; Nanoparticle; Se-NPs