Therapeutic effects of Lucilia sericata larval excretion/secretion products on Leishmania major under in vitro and in vivo conditions

Abstract

Background Leishmaniasis is a neglected infectious disease caused by protozoa of the genus Leishmania. The disease generally manifests as characteristic skin lesions which require lengthy treatment with antimonial drugs that are often associated with adverse side effects. Therefore, a number of studies have focused on natural compounds as promising drugs for its treatment. This study aimed to evaluate the effects of larval excretion/secretion products (ES) of Lucilia sericata in crude and fractionated forms on Leishmania major, by using in vitro and in vivo models. Methods The in vitro experiments involved evaluation of ES on both promastigotes and macrophage-engulfed amastigotes, whereas the in vivo experiments included comparative treatments of skin lesions in L. major-infected mice with Eucerin-formulated ES and Glucantime. Results The half maximal inhibitory concentrations of the crude ES, > 10-kDa ES fraction, < 10-kDa ES fraction, and Glucantime were 38.7 μg/ml, 47.6 μg/ml, 63.3 μg/ml, and 29.1 μg/ml, respectively. Significant differences were observed between percentage viabilities of promastigotes treated with the crude ES and its fractions compared with the negative control (P < 0.0001). The crude ES was more effective on amastigotes than the two ES fractions at 300 μg/ml. The macroscopic measurements revealed that the reduction of lesion size in mice treated with the crude ES followed quicker cascades of healing than that of mice treated with Glucantime and the ES fractions. Conclusions The present study showed that the larval ES of L. sericata in both crude and fractionated forms are effective for both intracellular and extracellular forms of L. major. Also, the ES exert both topical and systemic effects on mice experimentally infected with L. major. Graphical abstract

Evaluating leishmanicidal effects of Lucilia sericata products in combination with Apis mellifera honey using an in vitro model

“…Furthermore, significant decreases in parasite loads and survival indexes were observed in treated groups compared to the untreated control ( P = 0.05), which was consistent with findings of Rahimi et al [ 37 ]. Our study confirmed the result of Sherafati et al that honey acts as a synergist with ES products [ 30 ]. Indeed, leishmanicidal effects of larval ES products in combination with honey to intracellular amastigotes provide a promising basis for in vivo experimentation in future.…”

“…To obtain larval ES, about 100 stage II and III larvae of L . sericata were selected from previously established colonies and disinfected as described by Cruz-Saavedra et al [ 29 , 30 ]. The ES was collected by centrifugation at 4000 g for 10 minutes [ 17 ].…”

“…About 20–25 protein bands were observed for crude ES, which corresponded to bands in both the >10 kDa and <10 kDa fractions. The protein profiles of larval ES and its fractions were presented in our previous study [ 30 ]. The profile obtained from ES separation showed that the separation was done with high accuracy.…”