ABSTRACT
A tripanossomíase americana ainda constitui problema de saúde pública. O curso da infecção depende das características de cada isolado de Trypanosoma cruzi e do hospedeiro considerado. Foi aventada a hipótese de tropismo para o sistema nervoso central(SNC) de algumas cepas. Neste trabalho, foi testado o grau de infecção de encéfalos de ratos Holtzman imunossuprimidos. Foram utilizadas as cepas Y e PNM e o clone CL-Brener emratos Holtzman irradiados (irradiação gama 700 rad) aos 29 dias de idade e inoculados aos 30 dias. A imunossupressão aumentou a parasitemia sanguínea pelo T. cruzi para todas as cepas analisadas em relação aos animais-controle. Entretanto, para as condições do experimento atual não se verificou o neurotropismo do parasito, como se verifica na literatura. A parasitemia encontrada no SNC foi pequena em relação aos dados já publicados, possivelmente pelo pouco tempo de exposição ao parasita.
American trypanosomiasis is still a public health problem in Brazil and Latin America. The infection depends on the characteristics of each isolate of Trypanosoma cruzi and its host. The hypothesis of central nervous system (CNS) tropism has been proposed for certain strains. This work tested the infection rate of the encephalon of immunosuppressed Holtzman rats. The Y and PNM strains were used as well as the CL-Brener clone, inoculated in Holtzman rats irradiated (700 rad gamma) at 29 days of age and inoculated at 30 days of age. Immunosuppression increased the parasitemia by T. cruzi on SNC for all analyzed strains in comparison to the control animals. Neurotropism not was verified of T. cruzi under these conditions as in the literature. The parasitemia detected in the SNC was small compared to literature data, perhaps due to the short time of parasite exposure.
Subject(s)
Animals , Rats , Cerebrum , Immunosuppression Therapy , Rats, Sprague-Dawley , Trypanosoma cruziABSTRACT
Prenatal exposure to ethanol is frequently associated with micronecephaly, hypomyelinization, delayed cell migration, and impaired neuronal and glial maturation in the offspring. The mechanism by which ethanol induces its effects on the development of the nervous system is still not fully understood. In this study, the influence of acute prenatal exposure to ethanol on the prefrontal cortex cells of rats were examined. Three doses of ethanol (3g/kg of body weight) were administered intraperitoneally to pregnant female rats on the 12th day of pregnacy, at 8 hours intervals. Control rats received the same treatment but with a saline solution. Cells in the synthesis phase (S) of the cell cycle were labeled with bromodeoxyuridine. Six controls and 12 ethanol-treated neonates were sacrificed on the 8th day of postnatal life. The distance between nuclear cores in immunohistochemically labeled cells was determined by image analysis. Control rats had a normal neocortex, with six layers in the prefrontal region. Rats treated with ethanol showed ectopia of pyramidal neurons in layers I and II, heterotopia in the basal area of the prefrontal fissure, and a decrease in cellular density in layers I and VI of the cerebral prefrontal cortex. These alterations could help to explain some of the dysfunctions reported in patients with fetal alcohol syndrome.