Antileishmanial, cellular mechanisms, and cytotoxic effects of green synthesized zinc nanoparticles alone and in combined with glucantime against Leishmania major infection

We decided to investigate the antileishmanial, cellular mechanisms, and cytotoxic effects of green synthesized Zinc nanoparticles (ZnNPs) alone and combined with glucantime against Leishmania major infection. The effect of green synthesized ZnNP on L. major amastigote was studied through macrophage cells. The mRNA expression level of iNOS and IFN-γ followed by the exposure of J774-A1 macrophage cells to ZnNPs was assessed by Real-time PCR. The Caspase-3-like activity of promastigotes exposed to ZnNPs was studied. Effects of ZnNPs alone and combined with glucantime (MA) were studied on cutaneous leishmaniasis in BALB/c mice. ZnNPs displayed the spherical shape with sizes ranging from 30 to 80 nm. The obtained IC50 values for ZnNPs, MA, and ZnNPs + MA were 43.2, 26.3, and 12.6 µg/mL, respectively; indicating the synergistic effects of ZnNPs in combination with MA. CL lesions had completely improved in the mice received with ZnNPs in combination with MA. The mRNA expression level of iNOS, TNF-α, and IFN-γ was dose-dependently (p < 0.01) upregulated; whereas it was downregulated in IL-10. ZnNPs markedly stimulated the caspase-3 activation with no significant toxicity on normal cells. Based on these in vitro and in vivo results, green synthesized ZnNPs, mainly along with MA, showed that has the potential to be introduced as a new drug for CL therapy. Triggering of NO production, and inhibition of infectivity rate are revealed as mechanisms of action ZnNPs on L. major. But, supplementary investigations are necessary to clear the efficacy and safety of these agents.