Study on effects of cantharidin on cutaneous leishmaniasis, its mechanism and optimization of the therapeutic modes

Leishmaniasis is one of the major problems in many countries. Leishmania is flagellated protozoa and causative agent of leishmaniasis which is the most important health problem in many countries especially in developing country. Leishmania major causes cutaneous leishmaniasis (CL). CL is endemic in some part of Iran. Pentavalent antimony compounds are main therapy of CL, they have some side effects due to their toxicity, and also relapse is possible. Cantharidin is terpenoid and vesicant compound that can be found in Meloidae and Oedomeridae family beetles. It was used as treatment to cancer and Wart. It is also apoptosis inducer in various cancer cells. In this study, the effect of ۰.۵, ۱, ۲, ۵, ۱۰, ۲۰ and ۵۰ μg/ml cantharidin on the L. major promastigotes, non-infected macrophages and infected macrophages with parasite amastigotes was studied by (۳-(۴,۵-dimethyl thiazolyl-۲)-۲,۵-diphenyle tetrazolium bromide) MTT assay and flow cytometer in vitro. The Effect of cantharidin as ۰.۵, ۰.۰۵ and ۰.۱% ointment surveyed on the Leishmania lesions in BALB/C as well as. Parasite load as determined by Real Time PCR, and IFN-γ and IL-۴ was involved by ELISA. Results showed that the highest cytotoxicity (۵۶.۱۴%) in promastigotes was in a group that treated with ۵۰ μg/ml cantharidin after ۴۸h. The rate in non-infected macrophages and infected macrophages was ۱۳.۰۵ % and ۳۰.۱۷% respectively. Maximum cytotoxicity rate in promastigotes treated with ۵۰ μg/ml cantharidin after ۷۲ h was determined ۶۶.۴۸%, ۴۸.۵۲% in non- infected macrophages and ۶۲.۲۴% in infected macrophages after ۴۸h by flow cytometry. Group treated with ۰.۰۵% cantharidin had lowest rate of ulcer growth. Ulcer size was increased in group treated with ۰.۵% cantharidin. IFN-γ value in group treated with cantharidin was less than it in untreated (control) group, but IL -۴ didn’t change. Cantharidin through blister formation induces inflammatory reaction and neutrophils and macrophages infiltration in blister site .It can also destroy tissue by cytokines production stimulating such as myeloperoxidase. However, it can destroy parasite and infected macrophage through apoptosis inducing. Following more investigation, cantharidin can be introduced as cutaneous leishmaniasis treatment.

Keywords:

Leishmania major , Cantharidin , Macrophage , Apoptosis