Atividade do flavonóide quercetina em Leishmania braziliensis usando hamster como modelo de infecção

• Autor(a) principal: Santos, Rosiane Freire dos
• Data de Publicação: 2012
• Tipo de documento: Dissertação
• Idioma: por
• Título da fonte: Biblioteca Digital de Teses e Dissertações da UERJ
• Texto Completo: http://www.bdtd.uerj.br/handle/1/14410
• topic: Leishmania braziliensis; Quercetin; Hamster; Therapeutic activity; Leishmania braziliensis; Quercetina; Hamster; Atividade terapêutica; Leishmania braziliensis; Quercetina Uso terapêutico; CNPQ::CIENCIAS BIOLOGICAS::MICROBIOLOGIA

Leishmaniasis are among the most important endemic diseases in Brazil and are among the most neglected diseases in the world. The therapeutic tools available is restricted, toxic, expensive and ineffective in some situations, due to the emergence of resistant strains of the parasite are reported annually in Brazil more than 20.000 cases of cutaneous leishmaniasis. a Leishmania braziliensis is the main species causing clinical forms of skin and mucosa. Previous studies demonstrated therapeutic effect of quercetin flavonoid by oral route in mice infected with L. amazonensis. The aim of this study was to evaluate the activity of quercetina in Leishmania braziliensis in vitro and in vivo using hamsters as experimental model. The antiparasitic effect was evaluated in vitro on the growth of promastigotes and on intracellular amastigotes in mouse and hamsters peritoneal macrophages. The effect on the modulation of murine macrophage activation was assessed by measuring levels of nitric oxide(Griess reagent) and ROS by H2DCFDA. In vivo therapeutic activity of quercetin was studied in groups of hamsters infected with L.braziliensis in the paw, treated with oral routes by quercetin (2mg/ 5X / week) after 7 days of infection for eight weeks. The therapeutic action was analyzed using the size of the lesion. The immune response was evaluated during treatment by the response of delayed hypersensitivity (DTH) to the total antigen of L. braziliensis. Quercetin showed no activity in promastigotes forms in none of the concentration tested. The antiamastigote action is a dose dependent manner, in mice and hamsters macrophages treated for 48 hours inhibiting 45% e 54% and 25% e 48 %, respectively, at concentrations of 50 and 100 µg/ml. No inibihition was observed at concentration of 25 µg/ml. The pre- treatment of mice and hamsters macrophages inibihited 57, 58 e 74% e 49, 50, e 58%, respectively at the concentrations of 25, 50 and 100 µg/ml the growth of intracellular amastigotes, showing inhibitory effects on all concentrations tested. No production of nitric oxide was observed in macrophages. Pre treated macrophages before infection, shows an increase of ROS, when compared to controls, while macrophages treated before and after infection showed an decrease of ROS production. In vivo, quercetin was able to control de size of lesion since the third week of of treatment, when compared to untreated controls (P< 0,05). These dates show quercetin activity on L. braziliensis, inhibiting amastigote growth in vitro and being able to control lesion size in infected hamster when administred by oral route.