Effects of vitamin C supplementation on acute phase Chagas disease in experimentally infected mice with Trypanosoma cruzi QM1 strain

The tissue changes that occur in Chagas disease are related to the degree of oxidative stress and antioxidant capacity of affected tissue. Studies with vitamin C supplementation did not develop oxidative damage caused by Chagas disease in the host, but other studies cite the use of peroxiredoxins ascorbate - dependent on T. cruzi to offer protection against immune reaction. Based on these propositions, thirty "Swiss" mice were infected with T. cruzi QM1 strain and treated with two different vitamin C doses in order to study the parasitemia evolution, histopathological changes and lipid peroxidation biomarkers during the acute phase of Chagas disease. The results showed that the parasite clearance was greater in animals fed with vitamin C overdose. There were no significant differences regarding the biomarkers of lipid peroxidation and inflammatory process or the increase of myocardium in animals treated with the recommended dosage. The largest amount of parasite growth towards the end of the acute phase suggests the benefit of high doses of vitamin C for trypomastigotes. The supplementation doesn't influence the production of free radicals or the number of amastigote nests in the acute phase of Chagas disease.As alterações teciduais que ocorrem na doença de Chagas estão relacionadas ao grau de estresse oxidativo e à capacidade antioxidante do tecido afetado. Estudos realizados com suplementação de vitamina C revelaram redução no dano oxidativo causado no hospedeiro pela doença de Chagas, porém outros estudos citam o uso de peroxiredoxinas dependentes de ascorbato pelo T. cruzi para se proteger da ação imune. Com base nessas proposições, trinta camundongos "Swiss" foram infectados com a cepa QM1 de T. cruzi e tratados com duas diferentes doses de vitamina C para estudar a evolução da parasitemia, alterações histopatológicas e dosagem de biomarcadores de peroxidação lipídica durante a fase aguda da doença de Chagas. Os resultados mostraram que a parasitemia foi maior nos animais que receberam uma superdosagem de vitamina C. Não houve diferenças significativas quanto aos biomarcadores de peroxidação lipídica e houve maior processo inflamatório no miocárdio dos animais tratados com dosagem recomendada. O maior crescimento parasitário ao fim da fase aguda sugere benefício de altas doses de vitamina C aos tripomastigotas. A suplementação não exerceu influência sobre a produção de radicais livres e o número de ninhos de amastigotas na fase aguda da doença de Chagas

Com o diabo no corpo: os terríveis papagaios do Brasil colônia

Desde a Antiguidade, papagaios, periquitos e afins (Psittacidae) fascinaram os europeus por seu vivo colorido e uma notável capacidade de interação com seres humanos. A descoberta do Novo Mundo nada faria além de acrescentar novos elementos ao tráfico de animais exóticos há muito estabelecido pelos europeus com a África e o Oriente. Sem possuir grandes mamíferos, a América tropical participaria desse comércio com o que tinha de mais atrativo, essencialmente felinos, primatas e aves - em particular os papagaios, os quais eram embarcados em bom número. Contudo, a julgar pelos documentos do Brasil colônia, esses voláteis podiam inspirar muito pouca simpatia, pois nenhum outro animal - exceto as formigas - foi tantas vezes mencionado como praga para a agricultura. Além disso, alguns psitácidas mostravam-se tão loquazes que inspiravam a séria desconfiança de serem animais demoníacos ou possessos, pois só três classes de entidades - anjos, homens e demônios - possuíam o dom da palavra. Nos dias de hoje, vários representantes dos Psittacidae ainda constituem uma ameaça para a agricultura, enquanto os indivíduos muito faladores continuam despertando a suspeita de estarem possuídos pelo demônio. Transcendendo a mera curiosidade, essa crença exemplifica o quão intrincadas podem ser as relações do homem com o chamado “mundo natural”, revelando um universo mais amplo e multifacetado do que se poderia supor a princípio. Nesse sentido, a existência de aves capazes de falar torna essa relação ainda mais complexa e evidencia que as dificuldades de estabelecer o limite entre o animal e o humano se estendem além dos primatas e envolvem as mais inusitadas espécies zoológicas.Since ancient times, parrots and their allies (Psittacidae) have fascinated Europeans by their striking colors and notable ability to interact with human beings. The discovery of the New World added new species to the international exotic animal trade, which for many centuries had brought beasts to Europe from Africa and the Orient. Lacking large mammals, tropical America participated in this trade with its most appealing species, essentially felines, primates and birds - especially parrots - which were shipped in large numbers. It should be noted, however, that at times these birds were not well liked. In fact, according to documents from colonial Brazil, only the ants rank higher than parrots as the animals most often mentioned as agricultural pests. On the other hand, some of these birds were so chatty that people suspected them to be demonic or possessed animals, since only three classes of beings - angels, men and demons - have the ability to speak. Nowadays, several Psittacidae still constitute a threat to agriculture, and the suspicion that extremely talkative birds were demon possessed has also survived. More than a joke or a mere curiosity, this belief exemplifies how intricate man’s relationships with the “natural world” may be. In this sense, the existence of birds that are able to speak adds a further twist to these relationships, demonstrating that the problem of establishing a boundary between the animal and the human does not only involve primates, but also includes some unusual zoological species

EFFECTS OF VITAMIN C SUPPLEMENTATION ON THE CHRONIC PHASE OF CHAGAS DISEASE

Introdução: Para verificar a eficácia da vitamina C em combater o insulto oxidativo causado pelo Trypanosoma cruzi durante a evolução da fase crônica da doença de Chagas, camundongos Swiss foram previamente infectados via intraperitoneal com 5.0 × 104 tripomastigotas da cepa QM1 de T. cruzi. Métodos: Camundongos foram suplementados com duas diferentes doses de vitamina C por 180 dias. Foram mensurados os níveis de peroxidação lipídica (indicado por substâncias reativas ao ácido tiobarbitúrico-TBARS), peróxido total, vitamina C, e glutationa reduzida no plasma e TBARS, peróxido total e vitamina C no miocárdio, e foi realizado o estudo histopatológico em coração, cólon e músculo esquelético. Resultados: Animais que receberam diariamente uma dosagem equivalente a 500 mg de vitamina C apresentaram aumento na produção de ROS e RNS no plasma e no miocárdio e maior grau de inflamação e necrose em músculo esquelético em comparação àqueles que receberam doses menores ou nenhuma vitamina C. Conclusão: Embora muitas pesquisas tenham mostrado o efeito antioxidante da vitamina C, nossos resultados mostraram que os animais que foram expostos a 500 mg de vitamina C apresentaram maior dano tecidual na fase crônica da doença de Chagas, provavelmente devido a ações paradoxais desta substância, onde nesta patologia, poderá agir como pró-oxidante ou pró-inflamatória.Introduction: In order to examine the effectiveness of vitamin C (ascorbic acid) in combating the oxidative insult caused by Trypanosoma cruzi during the development of the chronic phase of Chagas disease, Swiss mice were infected intraperitoneally with 5.0 × 104 trypomastigotes of T. cruzi QM1strain. Methods: Mice were given supplements of two different doses of vitamin C for 180 days. Levels of lipid oxidation (as indicated by thiobarbituric acid reactive substances-TBARS), total peroxide, vitamin C, and reduced glutathione were measured in the plasma, TBARS, total peroxide and vitamin C were measured in the myocardium and histopathologic analysis was undertaken in heart, colon and skeletal muscle. Results: Animals that received a dose equivalent to 500 mg of vitamin C daily showed increased production of ROS in plasma and myocardium and a greater degree of inflammation and necrosis in skeletal muscles than those that received a lower dose or no vitamin C whatsoever. Conclusion: Although some research has shown the antioxidant effect of vitamin C, the results showed that animals subject to a 500 mg dose of vitamin C showed greater tissue damage in the chronic phase of Chagas disease, probably due to the paradoxical actions of the substance, which in this pathology, will have acted as a pro-oxidant or pro-inflammatory

Incidence of Trypanosoma cruzi transmission through breastfeeding during acute experimental Chagas disease

OBJECTIVE: To verify the incidence of T. cruzi transmission through breastfeeding during acute experimental Chagas' disease. METHODS: Fifteen female Swiss mice were mated and, after pregnancy confirmation, placed in individual cages. A few hours after birth, the females were inoculated with 0.1 mL of blood containing approximately 3 x 10(5) trypomastigote forms of Y strain of T. cruzi and continued breastfeeding for 25 days. RESULTS: In 142 offspring examined no infection through breast-feeding was observed. CONCLUSIONS: The low number of trypomastigote forms ingested by the newborn mice combined with biological and biochemical characteristics of blood trypomastigotes may explain the lack of transmission in this experiment

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

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 8.6x10-4mg/g of vitamin C daily, whereas G2 and G'2 received 7.14x10-3mg/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 11th day, but on the 22nd day it had greater parasitemia than in G2 and G3, and from the 36th 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)

Efeitos da suplementação de vitamina C sobre a fase aguda da doença de Chagas em camundongos experimentalmente infectados pela cepa QM1 de Trypanosoma cruzi

The tissue changes that occur in Chagas disease are related to the degree of oxidative stress and antioxidant capacity of affected tissue. Studies with vitamin C supplementation did not develop oxidative damage caused by Chagas disease in the host, but other studies cite the use of peroxiredoxins ascorbate - dependent on T. cruzi to offer protection against immune reaction. Based on these propositions, thirty "Swiss" mice were infected with T. cruzi QM1 strain and treated with two different vitamin C doses in order to study the parasitemia evolution, histopathological changes and lipid peroxidation biomarkers during the acute phase of Chagas disease. The results showed that the parasite clearance was greater in animals fed with vitamin C overdose. There were no significant differences regarding the biomarkers of lipid peroxidation and inflammatory process or the increase of myocardium in animals treated with the recommended dosage. The largest amount of parasite growth towards the end of the acute phase suggests the benefit of high doses of vitamin C for trypomastigotes. The supplementation doesn't influence the production of free radicals or the number of amastigote nests in the acute phase of Chagas disease