Efficacy of a Hemolymph-Based Cream Derived from Lucilia sericata Larvae in Treating Cutaneous Leishmaniasis: An In Vitro and In Vivo Study in BALB/c Mice

Abstract

Background: Cutaneous leishmaniasis (CL) is a neglected tropical disease with limited therapeutic options due to drug resistance, systemic toxicity, and prolonged treatment duration associated with pentavalent antimonials such as meglu­mine antimoniate (MAT). Lucilia sericata larvae produce hemolymph containing bioactive compounds with antimicro­bial and immunomodulatory properties, suggesting potential as an alternative or adjunct therapy for CL.

Methods: Hemolymph was extracted from sterile third-instar L. sericata larvae and characterized using SDS-PAGE and Fast Protein Liquid Chromatography. The antileishmanial activity of whole hemolymph, its most active fraction, MAT, and their combinations was assessed against promastigote and amastigote forms of L. major. Cytotoxicity, cyto­kine gene expression and reactive oxygen species production were evaluated. In vivo efficacy was examined in BALB/c mice infected with L. major and treated for 28 days with topical hemolymph cream, intramuscular MAT, or combina­tion therapy. Lesion size and parasite burden were measured.

Results: Whole hemolymph and the active fraction significantly inhibited parasite growth in vitro, while combination treatments showed strong synergistic effects. Treatments enhanced Th1-associated cytokines, suppressed Th2 cytokines, and increased reactive oxygen species production. In vivo, hemolymph cream reduced lesion size and parasite load, with the greatest improvement observed in the combination group. No significant cytotoxicity was detected.

Conclusions: Lucilia sericata larval hemolymph exhibits potent antileishmanial and immunomodulatory activity and rep­resents a promising and safe topical therapy for CL. Combination with MAT enhances efficacy and may reduce sys­temic toxicity.