A INFLUÊNCIA DA CEPA Y DE Trypanosoma cruzi NO CORAÇÃO EM RATOS WISTAR MACHOS SUBMETIDOS AO PROCESSO DE ADRENALECTOMIA.

A doença de Chagas é causada por um parasita intracelular - Trypanosoma cruzi, que provoca distintas patogenias com diferentes sintomatologias, dependendo do tipo de cepa e de seu tropismo, acometendo vários órgãos, sendo mais freqüentes o coração, baço, fígado, intestino e esôfago. O presente trabalho avalia as alterações histopatológicas do coração de ratos Wistar machos, infectados ou não com a cepa Y de Trypanosoma cruzi, que sofreram adrenalectomia com ou sem reposição de dexametasona, comparados com os grupos Controle e Sham. A análise do parasitismo tecidual foi realizada no 5º, 9º, 14º e 23º dias após o inóculo. Já a cariometria foi analisada no 9º dia de infecção, que corresponde ao pico parasitêmico. Observou-se maior parasitemia nos animais do grupo adrenalectomizado quando comparados aos demais; e o grupo adrenalectomizado com reposição de dexametasona apresentou os menores níveis parasitêmicos. No parasitismo tecidual constatou-se que dentre todos os órgãos, somente o coração obteve grande quantidade de ninhos de amastigotas, principalmente no 9º dia de infecção. Porém, não foram encontrados ninhos de amastigota nos demais órgãos. A cariometria apresentou alterações significativas, dependendo do tipo de órgão e dos grupos que foram comparados

Estudo comparativo do comportamento da infecção de camundongos, através da inoculação subcutânea e intraperitoneal, utilizando-se duas cepas do Trypanosona cruzi

By means of comparative studies of the infection of mice with T. cruzi using intraperitoneal and subcutaneous inoculation, it was concluded that more uniform and virulent infections are obtained after subcutaneous inoculation. This is due to an immediate cellular response, when intraperitoneal inoculations are used. With the aim of making comparative studies as between the two methods of inoculation, the intraperitoneal using two, morfologically distinct, strains of T. cruzi: Y with predominance of thin forms and Bolivia with predominance of broad forms. White mice of approximately 18g were required for these tests. The groups of animals received 2 x 10³, 2 x 10(4) and 2 x 10(5) trypanossomes per animal, and the course of the infection was subsequently observed. The results revealed that after subcutaneous inoculation when the Y strain was used in the tests, some significant differences appear, with more virulent and uniform infections. However, these did not appear when the Bolivia strain was used, because the animals showed the same standard parasitemy and other morpho-biological features, whether by subcutaneous or intraperitoneal inoculation. This incident suggests the existence of interrelation between the factors: method of inoculation represented by a greater or lesser presence of macrophages in the inoculated area, and the morphology of the blood forms represented by a greater or lesser capacity for cellular penetration.Foram utilizados camundongos brancos, pesando em média 18g e duas cepas de Trypanosoma cruzi, morfologicamente distintas: Y com predominância de formas sangüíneas delgadas e Bolívia com predomínio de formas largas. Os lotes de animais receberam 2 x 10³, 2 x 10(4) e 2 x 10(5) tripanossomos por animal e as vias de inoculação utilizadas foram a intraperitoneal e a subcutânea. Nos animais foi observado o curso de infecção. Os resultados obtidos revelaram que, nos experimentos em que se utilizou a cepa Y, existem algumas diferenças significantes, com infecções mais uniformes e virulentas, após inoculação subcutânea de 2 x 10³ e 2 x 10(4) formas sangüíneas de T. cruzi. Entretanto, isto não ocorreu com a cepa Bolívia, pois os animais apresentaram o mesmo padrão de parasitemia e os demais caracteres morfológicos, quer se utilizasse a via subcutânea ou intraperitoneal. Tal fato permite sugerir a existência de interrelação entre os fatores via de inoculação traduzida pela maior ou menor presença de macrófagos no sítio de inoculação, e a morfologia das formas sangüíneas representada pela maior ou menor capacidade de penetração celular

Effect Of Zinc Supplementation In Pregnant Mice During Experimental Trypanosoma Cruzi Infection.

Zinc is an essential micronutrient and has significant effects on human growth, development, and immune function. Zinc supplementation or deficiency may affect the course of infection. Zinc enhances immune response against a wide range of viral, bacterial, and parasitic pathogens. In the present study, we investigated the effects of zinc sulphate (ZnSO(4)) supplementation (20mg/kg/day) during pregnancy in mice, Swiss Webster strain infected by the Y strain of Trypanosoma cruzi. Oral supplementation of zinc sulphate in pregnant and non-pregnant infected animals did not affect the count of blood parasites as well as tissue parasitism in the heart, liver, and spleen. Zinc supplementation did not alter female body weight, the length of fetuses and neonates, placental size/weight and mortality rate. Among zinc supplied animals, no significant plasmatic zinc concentrations were observed. Concerning to tissue zinc concentrations, only the liver displayed enhanced values as compared to other organs. For placental parasitism, zinc supplied group displayed a significant decrease in amastigote burdens (P<0.05). However due to the reduced number of parasite burdens in placenta of animals supplied with zinc, these data suggest that zinc was partially effective in up-regulating the host's immune response against parasite, probably attenuating the infection in fetuses.90269-7

The Microbiota-Dependent Worsening Effects of Melatonin on Gut Inflammation

Dysbiosis and disturbances in gut homeostasis may result in dysregulated responses, which are common in inflammatory bowel diseases (IBD). These conditions may be refractory to the usual treatments and novel therapies are still necessary to reach a more successful regulation of intestinal immunity. The hormone melatonin (MLT) has been raised as a therapeutic alternative because of its known interactions with immune responses and gut microbiota. Hence, we evaluated the effects of MLT in experimental colitis that evolves with intestinal dysbiosis, inflammation and bacterial translocation. C57BL/6 mice were exposed to dextran sulfate sodium and treated with MLT. In acute colitis, the hormone led to increased clinical, systemic and intestinal inflammatory parameters. During remission, continued MLT administration delayed recovery, increased TNF, memory effector lymphocytes and diminished spleen regulatory cells. MLT treatment reduced Bacteroidetes and augmented Actinobacteria and Verrucomicrobia phyla in mice feces. Microbiota depletion resulted in a remarkable reversion of the colitis phenotype after MLT administration, including a counter-regulatory immune response, reduction in TNF and colon macrophages. There was a decrease in Actinobacteria, Firmicutes and, most strikingly, Verrucomicrobia phylum in recovering mice. Finally, these results pointed to a gut-microbiota-dependent effect of MLT in the potentiation of intestinal inflammation