-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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We carried out this work with the purpose of studying the effects of protein and vitamin B deficiency on the morphologic and quantitative aspects of the myenteric plexus of the descending colon of adult Rattus norvegicus. Twenty-eight rats were divided in two groups, one of them receiving chow with 22% protein level (control) and the other fed with chow having 8% protein level without vitamin B supplementation, during 120 days. Whole-mounts of the descending colon were prepared and stained with Giemsa, NADH-diaphorase and NADPH-diaphorase. The undernourished rats had a body weight 11.84% less than the control group. Relative to the controls, the experimental group had a colonic area 48% smaller, 51.9% less Giemsa-stained neurons, 28.3% less NADH-diaphorase positive neurons and 24.2% less NADPH-diaphorase positive neurons.

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787Pesq. Vet. Bras. 30(9):787-792, setembro 2010 RESUMO.-[Efeitos da infecção por oocistos de Toxoplasma gondii sobre a parede intestinal e o plexo mientérico de Gallus gallus.] O objetivo deste trabalho foi analisar os efeitos da infecção pelo Toxoplasma gondii sobre a parede intestinal e o plexo mientérico de Gallus gallus. Dez galinhas de 36 dias de idade separadas em dois grupos: controle e experimental inoculado com oocistos da cepa M7741 de T. gondii (genótipo III) pela via oral. Após 60 dias os animais foram submetidos à eutanásia e o duodeno coletado. Parte dos segmentos intestinais foi submetida à rotina histológica, coloração por HE e técnica histoquímica de PAS e Alcian Blue. Realizou-se uma avaliação qualitativa da parede intestinal e medidas comparativas entre os grupos da espessura da parede total, túnica muscular, muscular da mucosa e túnica mucosa. As célu-las caliciformes foram quantificadas. Outra parte dos seg- This paper aims to analyze the effects of the Toxoplasma gondii infection in the intestinal wall and myenteric plexus of chicken (Gallus gallus). Ten 36-day-old chickens were separated into two groups: control and experimental, orally inoculated with oocysts of the T. gondii strain M7741 genotype III. After 60 days the birds were submitted to euthanasia and had their duodenum removed. Part of the intestinal segments was submitted to histological routine, HE staining, PAS histochemical technique, and Alcian Blue. Qualitative analysis of the intestinal wall and comparative measurements among the groups with respect to total wall thickness, muscle tunic, mucosa, and tunica mucosa were carried out. Caliciform cells were quantified. The other part of the intestinal segments was fixed in formol acetic acid and dissected having the tunica mucosa and the tela submucosa removed. Neurons were stained with Giemsa, counted, and measured. Chickens from the experimental group presented diarrhea and inflammatory infiltrates in the tunica mucosa, thickness reduction of all the parameters assessed in the intestinal wall, and an increase of the number of caliciform cells. There was a ~70% reduction regarding the intensity of myenteric neurons; and the remaining cells presented a reduction of ~2.4% of the perikarion and ~40.5% of the nucleus (p<0.05). Chronic infection induced by T. gondii oocysts resulted in intestinal wall atrophy, mucin secretion increase, death and atrophy of chicken myenteric plexus neurons. Death and atrophy of myenteric plexus neurons may be related with the causes of diarrhea observed in chickens with toxoplasmosis. Effects of infection withINDEX TERMS: Chicken, toxoplasmosis, duodenum, enteric nervous system, experimental infection. mentos intestinais foi fixada em formol acético e dissecada retirando-se a túnica mucosa e a tela submucosa. Os neurônios foram corados pela técnica de Giemsa, contados e mensurados. Os animais do grupo experimental apresentaram diarréia e infiltrados inflamatórios na túnica mucosa, redução da espessura de todos os parâmetros avaliados da parede in...

This paper aims to verify the effects of severe protein malnutrition over the intestinal ascending colon morphometrics in adult rats. 12 rats (90 days old) were divided into 2 groups: control (n = 5) and malnutritioned (n = 7). In the following 90 days, the rats of the control group received a 24% protein chow as the malnourished group received 4% protein chow. The animals were submitted to euthanasia according to the anesthetic protocol. Colon segments were collected and submitted to routine histological processing. The cuts were stained with HE and histochemical techniques for mucines. The morphometric analyses showed the sustenance of the whole wall and muscle tunic thickness, as well as the reduction of the thickness of the mucosa tunic, the amount of goblet cells, the depth of the crypt and the height of the enterocytes as well as their nucleus on malnutritioned animals. The data suggest that protein malnutrition causes alterations on adult rat ascending colon intestinal morphometrics, especially in tissues which present a high level of cell turnover such as the mucosa tunic and consequently their structures such as the enterocytes, goblet cells, and crypts.

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