RESUMO

Human schistosomiasis is an important neglected tropical disease caused by blood flukes of the genus Schistosoma and is responsible for more than 280,000 deaths annually. Treatment for this disease relies currently on a single drug, praziquantel (PZQ). Concerns regarding PZQ resistance and insensitivity of juvenile schistosomes have increased the interest in resorting to medicinal plants for alternative drug therapies. This study aimed to perform an in vivo schistosomicidal activity evaluation of crude hexanic (HE) and ethanolic (EE) extracts obtained from Phyllanthus amarus in mice infected with Schistosoma mansoni (BH strain). Mice were treated orally with a single dose of 100 or 250 mg/kg, on two different infection periods, 30 and 45 days post-infection (dpi). Parameters such as worm recovery, faecal egg count, intestinal tissue egg count and liver histopathology were evaluated. Treatment against young adult (30 dpi) and adult (45 dpi) worms were more effective compared to the control group treated with PZQ. At a concentration of 250 mg/kg (30 dpi) EE showed a 54.4% female reduction and a 61.2% total worm reduction whilst at a concentration of 100 mg/kg (45 dpi) HE showed a 40.6% female worm reduction and a 45.3% total worm reduction. Histopathological examination showed a granuloma decrease in both number and size for groups treated with 250 mg/kg of HE (45 dpi) or EE (30 or 45 dpi). From these results, it can be concluded that both hexanic and ethanolic extracts have antischistosomal activities, however, act differently according to the parasites age. The schistosomicidal activity results in groups treated 30 days post infection is extremely important since praziquantel does not show activity against the juvenile forms of Schistosoma.

Assuntos

RESUMO

Different strains of Schistosoma mansoni can respond differently to conventional and experimental treatments. Therefore, the responses to potential schistosomicidal drugs must be checked with different parasite strains. This work aimed to analyze changes caused by different concentrations of artemisinin or artesunic acid administered on different days in the teguments of adult S. mansoni belonging to two Brazilian strains (BH and SJ), using scanning electron microscopy (SEM). Infected mice were treated with 300 or 500 mg/kg of artemisinin and artesunic acid, 30 or 45 days post infection. Fifteen days after treatment, worms were examined by SEM. Altered teguments were observed in males and females on both days of treatment with both compounds, but the injury with artesunic acid was more intense. The treatment utilizing 500 mg/kg of artesunic acid against the BH strain 30 days after the infection proved to be particularly effective, resulting in erosion, peeling, sensory structure damage, and vesicle formation on the tegument of males and females. It is concluded that artemisinin and artesunic acid showed qualitatively similar tegumentary changes in both genders of the BH and SJ parasite strains. However, changes induced by artesunic acid were more severe for the BH strain, which demonstrates greater susceptibility of this strain to this experimental treatment...

Alterações tegumentares em duas diferentes linhagens de Schistosoma mansoni submetidas a tratamento com artemisinina e ácido artesúnicoDiferentes linhagens de Schistosoma mansoni podem responder de formas distintas a tratamentos experimentais. Portanto, ensaios com potenciais fármacos esquistossomicidas necessitam ser realizados com várias linhagens. Este trabalho visou analisar as alterações causadas por diferentes concentrações de artemisinina e ácido artesúnico, administradas em diferentes dias, sobre o tegumento de adultos de S. mansoni de duas linhagens brasileiras (BH e SJ), utilizando-se microscopia eletrônica de varredura (MEV). Os camundongos infectados foram tratados com 300 e 500 mg/kg de artemisinina ou ácido artesúnico, 30 ou 45 dias após a infecção. Após 15 dias do tratamento, os vermes foram analisados pela MEV. A destruição do tegumento foi observada em machos e fêmeas nos dois dias de tratamento com ambos os compostos, mas observou-se que o ácido artesúnico provocou uma destruição mais intensa. O tratamento realizado com 500 mg/g de ácido artesúnico contra parasitos da linhagem BH, 30 dias após a infecção, mostrou ser o mais efetivo, resultando em erosão, descamação, destruição das estruturas sensoriais e formação de vesículas nos machos e nas fêmeas. Ficou evidenciado que as linhagens BH e SJ apresentaram alterações tegumentares diferentes quanto à intensidade, com ambos os compostos. No entanto, a destruição do tegumento foi mais intensa na linhagem BH, especialmente com o ácido artesúnico, o que demonstrou maior suscetibilidade desta linhagem a esse tratamento experimental...

Assuntos

RESUMO

The aim of this work was to identify the components of zooplankton that act as intermediate hosts of cestodes. One hundred and ninety four copepods of the suborder Calanoida, 317 copepods of the suborder Cyclopoida and 4240 cladocerans were collected in the Juqueri reservoir, in the state of São Paulo, from January to August, 2003. Only Copepods Calanoida of the genus Notodiaptomus sp. Kiefer were found to be infected and contained two distinct forms of metacestodes. The metacestodes, denominated Met 1 (order Proteocephalidea) and Met 2 (order Cyclophyllidea), had the following rates of prevalence and mean intensities of infection: Met 1 - 2.06 percent and 64 larvae/copepod and Met 2 - 0.52 percent and one larvae/copepod. The positive copepods were collected at the margins of the reservoir during the day. This finding suggest that parasitism may lead to a change in the behavior of the copepods and make them more susceptible to predation in shallow water.

Este trabalho teve o objetivo de identificar os componentes do zooplâncton que atuam como hospedeiros intermediários de cestódeos. Foram examinados 194 copépodos da subordem Calanoida, 317 copépodos da subordem Cyclopoida e 4240 cladóceros coletados no reservatório do Juqueri, Estado de São Paulo, entre janeiro e agosto de 2003. Apenas copépodos Calanoida do gênero Notodiaptomus sp. Kiefer encontravam-se positivos, sendo relatada duas formas morfológicas distintas de metacestódeos. Os metacestódeos, denominados Met 1 (Proteocephalidea) e Met 2 (Cyclophyllidea) apresentaram as seguintes prevalências e intensidades médias de infecção: Met 1 - 2,06 por cento e 64 larvas/copépodo e Met 2 - 0,52 por cento e uma larva/copépodo. Os copépodos positivos foram coletados na região litorânea do reservatório durante o dia, o que leva a crer que o parasitismo pode modificar o comportamento dos copépodos tornando-os mais acessíveis à predação.

RESUMO

Schistosomiasis mansoni is a chronic parasitic disease where much of the symptomatology is attributed to granuloma formation, an immunopathological reaction against Schistosoma eggs. To more clearly understand the immunopathology of schistosomiasis, the tissue microenvironment generated by S. mansoni infected mice was investigated. Using the hypoxia marker pimonidazole, we provide immunohistochemical evidence that hypoxia occurred in inflammatory cells infiltrated around the eggs and cells surrounding granulomas in the liver, intestine, spleen and lungs of infected mice. Hypoxia-inducible factor-1α (HIF-1α) was mainly expressed in inflammatory cells surrounding the eggs and in hepatocytes surrounding cellular and fibrocellular granulomas in infected mouse liver. HIF-1α expression was also verified in granulomas in the other tissues tested (intestine, spleen and lungs). Vascular endothelial growth factor (VEGF) expression was observed in the extracellular space surrounding inflammatory cells in liver granuloma. The VEGF expression pattern verified in infected mouse liver was very similar to that observed in the other tissues tested. A strong positive correlation occurred between pimonidazole binding and HIF-1α and VEGF expression in the tissues tested, except for lung. This work is the first evidence that infection by a helminth parasite, S. mansoni, produces a hypoxic tissue microenvironment and induces HIF-1α and VEGF expression.

Assuntos

RESUMO

A esquistossomose, uma importante doença no Brasil, é causada por trematódeo pertencente ao gênero Schistosoma, atingindo milhões de pessoas, numa das maiores regiões endêmicas dessa doença em todo globo. O principal objetivo desse trabalho foi sintetizar o derivado 6-formil-oxamniquina e avaliar sua atividade biológica. O derivado 6-formil- oxamniquina foi obtido por oxidação da oxamniquina com dióxido de manganês empregando diclorometano como solvente, à temperatura ambiente, por 24 horas. Sua obtenção foi confirmada por espectrometria na região de infravermelho e espectroscopia de RMN 13C e ÕH, apresentando atividade similar quando comparada à oxamniquina comercial (Mansil®).

Schistosomiasis, an important disease in Brazil, is caused by a trematode of the genus Schistosoma, reaching millions of person in one of the most endemic region of this disease in the whole globe. The main goal of this work was to syntetize the 6-formyl-oxamniquine derivative and evaluate its biological activity. The 6-formyl-oxamniquine derivative was obtained by the oxidation of oxamniquine with MnO2, applying CH2Cl2 as solvent at room temperature for 24 hours. The obtaintion of 6-formyl-oxamniquine derivative compound was confirmed by IR spectroscopy and 13C NMR and ÕH NMR, presenting similar activity when compared to the commercial oxamniquine (Mansil®).

Assuntos