Vitamin C effects in mice experimentally infected with Trypanosoma cruzi QM2 strain

Abstract

Introduction:To evaluate the efficacy of vitamin C in reducing the consequences generated by the production of free radicals in the acute and chronic phases of Chagas disease, two different doses of ascorbic acid were administered orally to 60 mice infected by Trypanosoma cruzi QM2 strain. Methods: The animals were divided into six groups: G1, G2, and G3 for the acute phase study, and G'1, G'2, and G'3 for the chronic stage. The groups G1 and G'1 received 8.6x10 -4 mg/g of vitamin C daily, whereas G2 and G'2 received 7.14x10 -3 mg/g daily. The other groups, G3 and G'3, were considered placebos and received 10µL of mineral water. Results: The study of the acute phase showed statistically significant differences between G1 and the other groups at various count days of the parasitemia evolution. The multiplying parasite was slower in G1 until the 11 th day, but on the 22 nd day it had greater parasitemia than in G2 and G3, and from the 36 th day on, parasitemia stabilized at higher levels. However, when the histopathology of acute and chronic phases is considered, one does not note significant differences. Conclusions: The administration of two different doses of vitamin C was not able to protect mice and to contain the oxidative stress caused by free radicals formed by the metabolism of oxygen (reactive oxygen species) and nitrogen (reactive nitrogen species). Keywords: Ascorbic acid. T. cruzi. Parasitemia. Free radicals. RESUMOIntrodução: Para avaliar a eficácia da vitamina C em reduzir as consequências geradas pela produção de readicais livres na fase aguda e crônica da doença de Chagas, duas diferentes dosagens de ácido ascórbico foram administradas oralmente para 60 camundongos infectados pela cepa QM2 de Trypanosoma cruzi. Métodos: Estes animais foram divididos em seis grupos: G1, G2 e G3 para o estudo da fase aguda e G'1, G'2 e G'3 para o estudo da fase crônica. Diariamente, G1-G'1 recebeu 8.6 x 10 -4 mg/g de vitamina C, G2-G'2 recebeu 7.14 x 10 -3 mg/g. Os outros grupos, G3-G'3, foram considerados placebos e receberam 10µL of de água mineral. Resultados: O estudo da fase aguda mostrou diferenças estatisticamente significativas entre G1 e os outros grupos em vários dias de contagens na evolução da parasitemia, e até o 11 o dia a multiplicação parasitária foi menor em G1, mas no 22 o dia ele tinha parasitemia maior que G2 e G3, e a partir do 36 o , a parasitemia estabilizou em altos níveis. Quando considerado o histopatológico da fase aguda e crônica, não foi notado, entretanto, diferença significativa. Conclusões: Assim, foi encontrado que a administração de duas diferentes dosagens de vitamina C não foi capaz de proteger o camundongo e conter o estresse oxidativo causado pelos radicais livres formados pelo metabolismo do oxigênio (ROS) e nitrogênio (RNS). Palavras-chaves: Acido ascórbico. T. cruzi. Parasitemia. Radicais livres.

Therapeutic Efficacy of a Subunit Vaccine in Controlling Chronic Trypanosoma cruzi Infection and Chagas Disease Is Enhanced by Glutathione Peroxidase Over-Expression

“…A recent study has shown a slower increase in blood parasitemia in mice given antioxidant (vitamin C) therapy, though authors noted no significant differences in tissue levels of T . cruzi and inflammatory infiltrate in chronic disease phase [46]. GPx deficiency has been linked to mutation of coxsackie virus B3 viral genome, with replacement of G base (most vulnerable to oxidation) at three of the seven sites [47], and enhanced myocarditis in Gpx1 -/- mice, though authors did not conclude enhanced viral burden.…”

Authors' reply: Vitamins in the treatment of chronic Chagas disease: adjuvant antiparasitary or antioxidant therapy?

“…Marim et al 5 have recently reported that vitamin C administration reduced parasitemia, although no effect was observed regarding the number of amastigote nets in the other tissues 6 . This phenomenon might limit the effi cacy of the combined treatment in the chronic phase, as other researchers have reported no statistically signifi cant histopathological differences in chronically infected mice that were treated with vitamin C for 180 days 7 .…”

The potential role of vitamins in the management of Chagas disease

“…In their recent article, Gusmão et al provided interesting data 1 . Vitamins may play a significant role in ameliorating the pathological effects of Chagas disease.…”

“…The potential role of vitamins in the management of Chagas disease Shailendra Kapoor [1] Dear Editor,…”

“…Alex Silva de Gusmão [1] , Roberto Esteves Pires Castanho [1] , Rodrigo Franzoso Almeida de Andrade [1] , Clarisse Moreno Farsetti [1] , Andressa Boim Mathias [1] , Altino Luiz Silva Therezo [1] and Luciamáre Perinetti Alves Martins [1] Dear Editor, We appreciate Dr. Shailendra Kappor interest in our research and his suggestions for future studies on the mechanisms of action of vitamins in the pathogenesis of Chagas disease. I, along with my research team, am contacting the references noted above and requesting permission to use their findings regarding the activity of vitamin B12 on Trypanosoma cruzi.…”