We carried out this study with the purpose of contributing on the effects of the proteic desnutrition on the morphological aspects and quantitative analysis of the neurons in the myenteric plexus of the ascending colon of adult Rattus norvegicus. Twenty adult rats were divided into two groups: in one of them, we offered a normal ration with proteic level of 22% (control group) and in the other, a ration with a proteic level of 8% (experiment group) during 120 days. We did the whole-mount preparations for the ascending colon and stained them with the Giemsa technique and the histochemical technique of NADH-diaphorase. The rats with proteic desnutrition showed a body weight, on average, to be 35.1% less than those of the control group, and the colon was on average, 26.8% shorter and 6.7% narrower. Thus, it was to be expected that the colon of animals with proteic desnutrition had a neuronal density 31.62% greater than the rats of the control group. Nevertheless, the difference with the Giemsa technique was on average 18.4%, demonstrating a mean neuronal loss of 13.25%.

-Alterations caused by a genotype III strain of Toxoplasma gondii were assessed with respect to the number and the morphometry of the myenteric neurons in the terminal ileum and the descending colon. Eighteen rats were divided into four groups: Acute Control Group (ACG, n=4); Acute Experimental Group (AEG, n=4); Chronic Control Group (CCG, n=5) and Chronic Experimental Group (CEG, n=5). NaCl solution was administered through gavage to the animals in the ACG and CCG. Toxoplasma gondii tachyzoites (10 4 ) from a genotype III strain were orally administered to the AEG and CEG. Acute Groups were died after 24 hours, and the Chronic Groups after 30 days. Neuronal loss was not observed in both organs. The neurons atrophied in the terminal ileum as the opposite occurred with the neurons at the descending colon during the chronic phase of infection. In the terminal ileum, the neurons atrophied during the chronic phase of the infection as no alteration was found during the acute phase. For the descending colon, the neurons became hypertrophic during the chronic infection in opposition to the atrophy found during the acute phase.KEY WORDS: enteric nervous system, toxoplasmosis, morphology. Alterações do plexo mientérico do íleo e cólon descendente causadas por Toxoplasma gondii (genótipo III)Resumo -Objetivou-se avaliar as alterações causadas por uma cepa genótipo III de Toxoplasma gondii, sobre o número e a morfometria de neurônios mientéricos, do íleo terminal e do cólon descendente. Dividiuse dezoitos ratos em quatro grupos: controle agudo (GCA, n=4), experimental agudo (GEA, n=4), controle crônico (GCC, n=5) e experimental crônico (GEC, n=5). Os animais do GCA e GCC receberam solução de NaCl por gavagem, e os animais do GEA e GEC 10 4 taquizoítos de uma cepa genótipo III de T. gondii por via oral. Os grupos agudos após 24 horas foram mortos e os crônicos após 30 dias. Observou-se que não houve perda neuronal em ambos os órgãos. No íleo terminal, os neurônios atrofiaram-se na fase crônica da infecção, enquanto nenhuma alteração ocorreu na fase aguda. Já no cólon descendente, os neurônios tornaram-se hipertróficos na fase crônica da infecção, em oposição à atrofia observada na fase aguda. PALAVRAS-CHAVE: sistema nervoso entérico, toxoplasmose, morfologia.

Toxoplasma gondii is an aetiological agent of toxoplasmosis, which commonly causes diarrhoea in a number of species. This observation and the parasite's affinity for the nervous tissue support the theory that T. gondii infection may affect the myenteric neurons. The aim of this study was to evaluate the changes caused by T. gondii (genotype III) in the myenteric neurons of the jejunum in rats. Fifteen rats were distributed into three groups: control (CG), inoculated for 30 days (G30) and inoculated for 90 days (G90). Rats from the G30 and G90 groups received an oral inoculum with 500 oocysts from a genotype III (M7741) T. gondii strain. At 180 days of age, all animals were anaesthetised and euthanised. Whole mounts were stained by using Giemsa (total population) and NADPH-diaphorase (nitrergic subpopulation) histochemistry. Maintenance of the width, length, area and neuronal density was observed; there was neuronal atrophy in the G30 group and a tendency to hypertrophy in the G90 group. Rats inoculated orally with sporulated oocysts did not show clinical illness or macroscopic or microscopic lesions, as do the majority of animal species. Therefore, infection was confirmed by a serum agglutination test; 30 days of infection caused increased weight gain and atrophy of myenteric neurons. At 90 days post-infection, weight gain became normal, and myenteric neurons hypertrophied.

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-The aims of this work were to evaluate the effects of the deficient ingestion of protein and vitamin B on the biochemical and hematologic parameters and on the NADH-and NADPH-diaphorase positive myenteric neurons. The control animals (n=10) received commercial chow and the experimental rats (n=10) received chow with protein level reduced to 8% during 120 days. At the time of killing blood was collected for assessment of the blood and hematologic parameters and the ascending colon for quantitative analysis of the neurons of the myenteric plexus. It was observed that the reduction of the protein level to 8% coupled to the reduction of the levels of vitamin B in adult rats neither led to qualitative or quantitative changes on red or white blood cells, nor decreased globulin levels, induced the formation of edema or gave rise to clinical signs typical of protein or vitamin B deficiency. On the other hand, the experimental protocol led to less weight gain, change on the body composition with fat deposition; decrease of the values of serum total protein and albumin; reduction of the area of colon and density of nitrergic and NADH-diaphorase myenteric neurons inferior to the expected.KEY WORDS: enteric neurons, proteic desnutrition, ascending colon, hematology, vitamin B.Efeitos da deficiência de proteínas e vitamina B sobre parâmetros sanguíneos e neurônios mioentéricos do colo de ratos adultos RESUMO -Os objetivos deste trabalho foram avaliar as repercussões da ingestão deficiente de proteínas e vitaminas do complexo B sobre parâmetros bioquímicos e hematológicos e neurônios mientéricos NADH e NADPH-diaforase positivos. Os animais controle (n=10) receberam ração comercial e os animais experimentais (n=10) ração com teor protéico reduzido para 8% durante 120 dias. Durante o sacrifício, coletou-se o sangue dos animais para avaliação de parâmetros sanguíneos e hematológicos e o colo ascendente para a análise quantitativa dos neurônios do plexo mioentérico. Observou-se que a redução do teor de proteínas na dieta para 8% associado a redução no teor de vitaminas do complexo B em ratos adultos, não causa alterações qualitativas e quantitativas das células sanguíneas das séries vermelha e branca, não leva a redução do valor da globulina nem a formação de edema ou ao surgimento de sinais clínicos característicos das carências de proteínas e vitaminas do complexo B. Por outro lado causa: menor ganho de peso corporal; alteração da composição corporal com acúmulo de gordura; redução nos valores de proteína total e albumina; redução na área do colo e evidenciação de densidade de neurônios nitrérgicos e NADH-diaforase positivos inferior ao esperado.PALAVRAS CHAVE: neurônios entéricos, desnutrição protéica, colo ascendente, hematologia, vitamina B. The utilization of animal models in studies of food restriction with known and controlled diets has as an advantage the improved knowledge about the many aspects of the human desnutrition 1 . Research on desnutrition aimsat simulating natural conditions, which involve deficienc...

Define an experimental model by evaluating quantitative and morphometric changes in myenteric neurons of the colon of mice infected with Trypanosoma cruzi. Twenty-eight Swiss male mice were distributed into groups: control (CG, n=9) and inoculated with 100 (IG 100 , n=9) and 1000 (IG 1000 , n=10) blood trypomastigotes, Y strain-T. cruzi II. Parasitemia was evaluated from 3-25 days post inoculation (dpi) with parasites peak of 7.7 × 10 6 and 8.4 × 10 6 trypomastigotes/mL at 8 th dpi (p>0.05) in IG 100 and IG 1000 , respectively. Chronic phase of the infection was obtained with two doses of 100mg/Kg/weight and one dose of 250mg/Kg/weight of Benznidazole on 11, 16 and 18 dpi. Three animals from each group were euthanized at 18, 30 and 75 dpi. The colon was stained with Giemsa. The quantitative and morphometric analysis of neurons revealed that the infection caused a decrease of neuronal density on 30 th dpi (p<0.05) and 75 dpi (p<0.05) in IG 100 and IG 1000 . Infection caused death and neuronal hypertrophy in the 75 th dpi in IG 100 and IG 1000 (p<0.05, p<0.01). The changes observed in myenteric neurons were directly related to the inoculate and the time of infection.