RESUMO
Cystic echinococcosis is a zoonotic disease caused by the larval stage of the cestode Echinococcus granulosus. The drugs commonly used against cystic echinococcosis are benzimidazoles. Unfortunately, 20%-40% of cases do not respond favorably to such chemotherapy. Consequently, the search of new therapeutic alternatives such as the use of traditional medicinal plants has been increased. The aim of the current experimental work was to investigate the chemoprophylactic and clinical efficacy of thymol on mice infected with E. granulosus metacestodes. Thymol (40 mg/kg) was administered under two different therapeutic schemes: dosing every 24h over 20 days and treatment every 12h for 10 days. Thymol demonstrated efficacy against experimental murine cystic echinococcosis. The chemoprophylactic and therapeutic effects of thymol were comparable to that of albendazole. Due to the lack of toxicity observed in mice at the tested doses; we consider that thymol is a potential alternative to be applied for the treatment of human hydatid disease.
Assuntos
Anti-Helmínticos/uso terapêutico , Equinococose/tratamento farmacológico , Timol/uso terapêutico , Albendazol/uso terapêutico , Animais , Equinococose/parasitologia , Equinococose/patologia , Camundongos , Microscopia Eletrônica de Varredura , Microscopia Eletrônica de TransmissãoRESUMO
Human cystic echinococcosis is a zoonosis caused by the metacestode stage of the tapeworm Echinococcus granulosus. Although benzimidazole compounds such as albendazole and mebendazole have been the cornerstone of chemotherapy for the disease, there is often no complete recovery after treatment. Hence, in searching for novel treatment options, we examined the in vitro efficacies of 5-fluorouracil (5-FU) and paclitaxel (PTX) against E. granulosus germinal cells, protoscoleces and cysts. 5-FU or PTX inhibited the growth of E. granulosus cells in a time dependent manner. Although both treatments had a protoscolicidal effect, 5-FU had a considerably stronger effect than PTX. 5-FU produced a dose- and time-dependent effect, provoking the complete loss of viability after 24 days of incubation. Moreover, cysts did not develop following the inoculation of treated protoscoleces into mice. The loss of viability was slower in PTX treated protoscoleces, reaching to approximately 60% after 30 days. The results of the in vitro treatment with 5-FU and PTX were similar in secondary murine cysts. The employment of SEM and TEM allowed us to examine, at an ultrastructural level, the effects induced by 5-FU and PTX on E. granulosus germinal cells, protoscoleces and murine cysts. In conclusion, the data obtained clearly demonstrated that 5-FU and PTX at clinically achievable concentrations inhibit the survival of larval cells, protoscoleces and metacestodes. In vivo studies to test the antiparasitic activities of 5-FU and PTX are currently being undertaken on the murine model of cystic echinococcosis.