Efficacy of biogenic selenium nanoparticles against Leishmania major: In vitro andin vivo studies

Project: This study investigated the in vitro and in vivo effectiveness of biogenic selenium nanoparticles(Se NPs), biosynthesized by Bacillus sp. MSh-1, against Leishmania major (MRHO/IR/75/ER). Procedure:The 3-(4,5-dimethylthiozol-2-yl)-2,5-diphenyl-tetrazolium bromide (MTT) assay was used to evaluatethe cytotoxicity effects of the biogenic Se NPs against both promastigote and amastigote forms of L.major. In a separate in vivo experiment, we also determined the preventive and therapeutic effects ofbiogenic Se NPs in BALB/c mice following subcutaneous infected with L. major. Results: The MTT assaysshowed that the highest toxicity occurred after 72 h against both promastigote and amastigote formsof L. major. The cytotoxicity of Se NPs was higher at all incubation times (24, 48, and 72 h) against thepromastigote than the amastigote form (p < 0.05). The 50% inhibitory concentrations (IC50) of the Se NPswere 1.62 ± 0.6 and 4.4 ± 0.6 �g ml−1against the promastigote and amastigote forms, respectively, aftera 72-h incubation period. Apoptosis assays showed DNA fragmentation in promastigotes treated with SeNPs. In an animal challenge, prophylactic doses of biogenic Se NPs delayed the development of localizedcutaneous lesions. Moreover, daily administration of Se NPs (5 or 10 mg kg−1day−1) in similarly infectedBALB/c mice that had not received prophylactic doses of Se NPs also abolished the localized lesions after14 days. Conclusion: Based on these in vitro and in vivo studies, biogenic Se NPs can be considered as anovel therapeutic agent for treatment of the localized lesions typical of cutaneous leishmaniasis