Atividade in vitro da fosfolipases A2 e da fração peptídica extraídas do veneno de Crotalus durissus terrificus sobre formas amastogotas e promastigotas de Leishmania (L) infantum chagasi

Detalhes bibliográficos
Ano de defesa: 2014
Autor(a) principal: Barros, Gustavo Adolfo Calsolari de [UNESP]
Orientador(a): Não Informado pela instituição
Banca de defesa: Não Informado pela instituição
Tipo de documento: Dissertação
Tipo de acesso: Acesso aberto
Idioma: por
Instituição de defesa: Universidade Estadual Paulista (Unesp)
Programa de Pós-Graduação: Não Informado pela instituição
Departamento: Não Informado pela instituição
País: Não Informado pela instituição
Palavras-chave em Português:
Link de acesso: http://hdl.handle.net/11449/113877
Resumo: American visceral leishmaniasis is caused by the intracellular parasite Leishmania ( L ) infantum chagasi , and transmitted by sand fly Lutzomyia longipalpis. Treatment is based on classical chemotherapeutics with significant side effects and the search for new drugs is the greatest global challenge. Thus , this in vitro study aimed to evaluate the anti - leishmanicidal effect of Crotalus durissus terrificus venom’s fractions on promastigotes and amastigotes of Leishmania (L) infantum chagasi. The whole venom were purified two fractions called respectively phospholipase A2 (PLA2) and peptide. Furthermore, promastigotes and macrophage infected per amastigotes were exposed to serial dilutions of the peptide fraction and PLA2 at intervals varying between 1.5625 μg/mL and 200 μg/mL. Both showed activity against promastigotes and varies according to the tested doses and the time of incubation. The MTT assay (3-(4,5-Dimethyl-1,3- thiazol-2-yl)-3,5-diphenyl-2H-tetrazol-3-ium bromide) against promastigotes showed IC50 of 52.07 μg/mL to PLA2, and 16.98 μg/mL for peptide venom’s fraction. The MTT assay to evaluate the cytotoxicity in peritoneal macrophages showed an IC50 of 98 μg/mL for PLA2 and 16.98 μg/ml for peptide. In peritoneal macrophages infected by Leishmania (L) infantum chagasi amastigotes the PLA2 stimulated growth of parasites, at higher doses was able to control 23 % growth. The peptide fraction controlled 43 % of the intracellular parasite growth at a dose of 16.98 μg/mL, showing up this dose toxic to macrophages . Both fractions stimulated H2O2 production by macrophages but only PLA2 was able to stimulate NO production . The results encourage further studies to describe the metabolic pathways involved in cell death , as well as the prospect of molecules with antiparasitic activity present in the peptide fraction of Crotalus durissus terrificus