title: No evidence of oxidant events in amphotericin B cytotoxicity versus L. infantum promastigotes.
abstract: Amphotericin B is used for the treatment of systemic mycoses and visceral leishmaniasis. The objective of our study was to evaluate the impact of catalase, ascorbic acid and ketoconazole on the amphotericin B toxicity towards Leishmania promastigotes membrane by two flow cytometric tests, the membrane potential assay using a cationic dye, [DiOC5(3)], and the membrane permeability test using propidium iodide. The collapse of membrane potential appeared at amphotericin B concentrations weaker than those assessed by the membrane permeability test. The binding of amphotericin B to membrane sterol was not modified by catalase or ascorbic acid whereas amphotericin B-induced growth inhibition could be modulated by these products. The permeabilizing effect of amphotericin B on parasite membrane was strongly reduced in the presence of ketoconazole. These results confirmed the pore hypothesis of amphotericin B action and suggested that flow cytometric methods constituted a valuable alternative to conventional methods for assessing the effect of drugs on cellular membrane and evaluating parasite susceptibility to polyene antibiotics.
authors.affiliation: Laboratoire de Parasitologie, Faculté de Pharmacie, 27, boulevard Jean Moulin, 13385 Marseille, France. Nadine.Azas@pharmacie.univ-mrs.fr
authors.forename: N
authors.initials: N
authors.lastname: Azas
authors.forename: C
authors.initials: C
authors.lastname: Di Giorgio
authors.forename: F
authors.initials: F
authors.lastname: Delmas
authors.forename: M
authors.initials: M
authors.lastname: Gasquet
authors.forename: P
authors.initials: P
authors.lastname: Timon-David
mesh_terms: D000666:Amphotericin B / Q000378:metabolism / Q000494:pharmacology*; D000818:Animals; D000935:Antifungal Agents / Q000494:pharmacology; D000975:Antioxidants / Q000494:pharmacology; D000981:Antiprotozoal Agents / Q000378:metabolism / Q000494:pharmacology*; D001205:Ascorbic Acid / Q000494:pharmacology; D002374:Catalase / Q000494:pharmacology; D002462:Cell Membrane / Q000187:drug effects / Q000502:physiology; D002463:Cell Membrane Permeability / Q000187:drug effects; D005434:Flow Cytometry; D007654:Ketoconazole / Q000494:pharmacology; D018314:Leishmania infantum / Q000187:drug effects* / Q000254:growth & development / Q000502:physiology; D007898:Leishmaniasis, Visceral / Q000188:drug therapy*; D008564:Membrane Potentials / Q000187:drug effects; D009181:Mycoses / Q000188:drug therapy*; D021261:Parasitic Sensitivity Tests / Q000379:methods
chemical_list: D000935:Antifungal Agents; D000975:Antioxidants; D000981:Antiprotozoal Agents; D000666:Amphotericin B; D002374:Catalase; D001205:Ascorbic Acid; D007654:Ketoconazole