ABSTRACT In the Amazon region, andiroba (Carapa guianensis) oil is among the most used products by the local population due to its medicinal properties. Previously, our group described the leishmanicidal activity of three limonoid-rich fractions from andiroba oil. This work aimed to evaluate the antioxidant activity and ultrastructural changes in Leishmania amazonensis treated with these limonoid-rich fractions from andiroba oil: 6α,11β-diacetoxygedunin; 11β-hydroxygedunin; and a fraction with both 6α,11β-diacetoxygedunin +11β-hydroxygedunin. The antioxidant activity was evaluated by the DPPH method and ultrastructural changes were evaluated by transmission electron microscopy. The fraction with both 6α,11β-diacetoxygedunin + 11β-hydroxygedunin displayed the best antioxidant activity (IC50 330.35 ± 8.60 µg mL-1; p=0.0022) compared to the 6α,11β-diacetoxygedunin fraction. The three fractions induced structural changes to mitochondria and kinetoplasts of L. amazonensis, in addition to lipid bodies, vacuolization, and vesicles in the flagellar pocket, indicating that the limonoid-rich fractions from andiroba oil can induce structural damage to Leishmania.

RESUMO Na região Amazônica, o óleo de andiroba (Carapa guianensis) é um dos produtos mais utilizados pela população local devido às suas propriedades medicinais. Anteriormente, nosso grupo descreveu a atividade leishmanicida de três frações do óleo de andiroba ricas em limonóides. Este trabalho objetivou avaliar a atividade antioxidante e alterações ultraestruturais em Leishmania amazonensis tratadas com essas frações ricas em limonóides do óleo de andiroba: 6α,11β-diacetoxigedunina; 11β-hidroxigedunina; e uma fração com ambas 6α,11β-diacetoxigedunina + 11β-hidroxigedunina. A atividade antioxidante foi avaliada pelo método DPPH, e alterações ultraestruturais foram avaliadas por microscopia eletrônica de transmissão. A fração com ambas 6α,11β-diacetoxigedunina + 11β-hidroxigedunina exibiu a melhor atividade antioxidante (IC50 = 330,35 ± 8,60 µg mL-1; p = 0.0022) comparado com a fração 6α,11β-diacetoxigedunina. As três frações induziram alterações estruturais nas mitocôndrias e cinetoplasto de L. amazonensis, além de corpúsculos lipídicos, vacuolizações e vesículas na bolsa flagelar, indicando que as frações ricas em limonóides do óleo de andiroba podem induzir dano estrutural a Leishmania.

BACKGROUND Leishmaniasis is a parasitosis caused by several species of the genus Leishmania. These parasites present high resistance against oxidative stress generated by inflammatory cells. OBJECTIVES To investigate oxidative stress and molecular inflammatory markers in BALB/c mice infected with L. amazonensis and the effect of antioxidant treatment on these parameters. METHODS Four months after infection, oxidative and inflammatory parameters of liver, kidneys, spleen, heart and lungs from BALB/c mice were assessed. FINDINGS In liver, L. amazonensis caused thiol oxidation and nitrotyrosine formation; SOD activity and SOD2 protein content were increased while SOD1 protein content decreased. The content of the cytokines IL-1β, IL-6, TNF-α, and the receptor of advanced glycation endproducts (RAGE) increased in liver. Treatment with the antioxidant N-acetyl-cysteine (20 mg/kg b.w) for five days inhibited oxidative stress parameters. MAIN CONCLUSIONS L. amazonensis induces significant alterations in the redox status of liver but not in other organs. Acute antioxidant treatment alleviates oxidative stress in liver, but it had no effect on pro-inflammatory markers. These results indicate that the pathobiology of leishmaniasis is not restricted to the cutaneous manifestations and open perspectives for the development of new therapeutic approaches to the disease, especially for liver function.

O presente estudo objetivou descrever alguns fatores relacionados à positividade de cães para leishmaniose visceral, em área endêmica do Estado do Rio Grande do Norte. Foram analisados 198 cães, dos quais 62 foram recrutados de propriedades rurais e 136 de residências urbanas. O diagnóstico foi realizado através dos testes de imunofluorescência indireta e imunoadsorção enzimática. Dos cães analisados, 45% dos positivos eram provenientes da área rural e 35% da área urbana. Analisando a função dos animais, a prevalência foi de 50% dos cães de guarda nas áreas rural e de 43% na área urbana. Quanto aos cães que tinham contato com outros cães de origem rural ou urbana, a prevalência observada de foi 54% e 32%, respectivamente. No que se refere ao sexo, as fêmeas da zona rural foram mais prevalentes. Estes resultados sugerem uma atenção maior sobre o papel destes animais como reservatório dessa zoonose, como também na urbanização da leishmaniose visceral e o inquérito epidemiológico desta doença, no qual estas informações poderão contribuir para o planejamento de estratégias de controle do cão como reservatório doméstico.

This study aimed at describing several factors related to positive testing of dogs for visceral leishmaniasis, in an endemic area of the state of Rio Grande do Norte. Sera of 198 dogs were analyzed, 62 from rural properties and 136 from urban residences. Diagnosis was performed through indirect immunofluorescence and enzyme-linked immunosorbent assay. Forty five percent of positive dogs were from the rural area and 35% came from the urban area. Concerning the analysis of dogs' function, the watchdogs showed greater prevalence, with 50% prevalence in the rural area and 43% in the urban area. With regard to contact with other dogs and origin in rural or urban areas, the prevalence was 54% and 32% respectively. In relation to gender, females from the rural area were more prevalent. These results suggest more attention should be paid to dogs as reservoirs for this zoonosis, as well as their important role in the urbanization of Leishmaniasis and in epidemiological survey of the disease. These data can contribute to the planning of strategies for control, targeting dogs as domestic reservoirs.

Congenitally athymic nude Balb/c (nu/nu) and their phenothypically normal adult and neonate littermates (nu/+), the C3H/HeN as well, were intraperitoneally infected with two strains (Y or CL) of Trypanossoma cruzi. The nude mice and the neonates developed a severe parasitaemia, the susceptible C3H/HeN also presented high level and adult Balb/c mice presented parasitaemia similar to that observed in outbred mice. Erythematous skin lesions were observed initially in infected athymic nude and neonates, being charactherized by nests of amastigotes in the dermis; in C3H/HeN infected mice no nest of parasite was observed but a low-grade inflammatory reaction was seen. In adult Balb/c or OF1 outbred mice nest was found but discreet inflammatory reaction was observed in severe infections.

Different patterns of cutaneous leishmaniasis can be induced when a challenge of alike dose of Leishmania amazonensis amastigotes in various inbred strains was applied. Two strains of mice, the Balb/c and C57 BL/10J, showed exceptional suscepbility, and 10(elevado a sexta potência) amastigotes infective dose lead, to ulcerative progressive lesions with cutaneous metastasis and loss by necrosis of leg on wich the footpad primary lesion occured. Lesions were also progressive but in a lower degree when C3H/HeN and C57BL/6 were infected. Lesions progress slowly in DBA/2 mice presenting lesions wich reach a discreet peack after 12 weeks, do not heal but do not uncerate. DBA/2 mice is, therefore, a good model for immunomodualtion. In attempt to determine the influence of BCG in vaccination schedule using microsomal fraction, DBA/2 became an excellent model, since it is also a non-responder to BCG. Vaccination of DBA/2 mice, receiving the same 10(elevado a sexta potência) BCG viable dose and 10 *g or 50 *g of protein content of microsomal fraction, lead to a progressive disease with time course similar to those observed in susceptible non-vaccinated C57BL/10J mice after 6 months of observation. An enhancement of infection in BCG non-responder mice suggests that use of BCG as immunostimulant in humans could be critical for both vaccination and immunoprophylactic strategies.