in vitro study on cytotoxic effects of zno nanoparticles on promastigote and amastigote forms of leishmania major (mrho/ir/75/er).

background: although pentavalent antimony compounds are used as antileish-manial drugs but they are associated with limitations and several adverse complica-tions. therefore, always effort to find a new and effective treatment is desired. in this study, the effect of zno nanoparticles with mean particle size of 20 nanome-ters (nm) on leishmania major promastigotes and amastigotes was evaluated. methods : viability percentage of promastigotes after adding different concentra-tions of zno nanoparticles (30, 60, 90 and 120 μg/ml) to the parasite culture was evaluated by mtt assay. in the flow cytometry study, annexin v-fitc apoptosis detection kit was used to study the induced apoptosis and necrotic effects. result : ic50 after 24 hours of incubation was 37.8 μg/ml. zno nanoparticles ex-ert cytotoxic effects on promastigotes of l. major through the induction of apopto-sis. a concentration of 120 μg/ml of zno nanoparticles induced 93.76% apoptosis in l. major after 72 hours. conclusion: zno nps can induce apoptosis in l. major by dose and time-de-pended manner in vitro condition.