Atividade in vitro e in vivo da pterocarpanoquinona LQB-118 sobre Trypanosoma cruzi

• Autor(a) principal: Brito, Andréia Carolinne de Souza
• Data de Publicação: 2016
• 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/1/14464
• topic: Trypanosoma cruzi; Pterocarpanquinone LQB-118; Chemotherapy; ROS; In vivo; Trypanosoma cruzi; Pterocarpanoquinona LQB-118; Quimioterapia; ROS; In vivo; Trypanosoma cruzi; Antiparasitários; Quimioterapia; Espécies de oxigênio reativas; CNPQ::CIENCIAS BIOLOGICAS::PARASITOLOGIA::PROTOZOOLOGIA DE PARASITOS

Chagas disease is caused by the protozoan Trypanosoma cruzi and endemic in Latin America, especially in Brazil. The therapy is very limited, not being effective in the chronic phase of infection. The LQB-118 pterocarpanoquinona shows antitumor and antileishmanial activities. Previous studies from our group have shown preliminarily that LQB-118 has an in vitro effect on trypomastigotes and intracellular pimastigot of T. cruzi (Dm28c clone). The aim of this work was to study in vitro the LQB-118 mechanism of action and evaluate its activity by the in vivo infection experimental model. Epimastigotes of T. cruzi (Dm28c clone) were incubated in the presence or absence of LQB-118 (0-5μM) for 96h/27°C and quantified daily by Neubauer chamber. An ultrastructural evaluation of pimastigota treated 2μM LQB-118 for 24/27°C was performed by transmission electron microscopy. The production of reactive oxygen species (ROS) was evaluated in pimastigota incubated in the presence or absence of LQB-118 (0-20μM) for 30 minutes to 48 hours/27°C and subsequently labeld with DHE probe. Tests using the antioxidant MitoTEMPO and pro-oxidant Antimycin A for 30 minutes were carried out using, cells treated with 10 or 20μM LQB-118. In silico analysis of the pharmacokinetic parameters was performed using the ADMET program. In vivo, two assays were conducted using Swiss mice were infected with 103 blood trypomastigotes (Y strain) intraperitoneally. In the first test, mice were treated orally with LQB-118 (20 mg/kg/day), for 11 days from the 7º day post-infection (dpi) and in the second were treated orally with LQB-118 (40 mg/kg/day, for 12 days from 4º dpi). We evaluated the parasitemia, survival rates, organ weights, biochemical parameters analysis of serum and preliminary histopathology in the heart. The LQB-118 was able to inhibit significantly (p<0.0001) the growth of the parasites at 48h and after 96h the inhibition was 99,67% at 5 uM. The IC50 in 48 hours was 2,34 ± 0,20μM and 96h was 0,88 ± 0,08μM. In ultrastructural evaluation, we observed in the morphology of the endoplasmic reticulum changes, swelling of the kinetoplast region and vacuoles near the flagellar pocket. We observed that LQB-118 induced increase parasite ROS production at 30 minutes of incubation when treated with 10μM and 20μM of LQB-118, respectively. The parasitemia in animals treated in LQB-118 decreased both assays. In the first experiment, the 15° dpi, the parasitemia reduction was 37,8%. In the second test, the parasitemia reduction was observed from the 11° dpi, a decrease of 49,47% (p<0.02) at 11º dpi, and 50,17% at 16º dpi. Serum biochemical analysis showed that there was a creatine decrease in animals treated with LQB-118. Preliminary histological analysis and indicated a cardiac damage decrease in the treated animals. These results showed that LQB-118 has activity against T. cruzi causing alteration in the parasite ROS production and has protective action in vivo during the infection acute phase.