Marcelo Biondaro Góis

Toxoplasma gondii causes death and plastic alteration in the jejunal myenteric plexus

AIM To assess the effects of ME-49 Toxoplasma gondii (T. gondii) strain infection on the myenteric plexus and external muscle of the jejunum in rats. METHODS Thirty rats were distributed into two groups: the control group (CG) (n = 15) received 1 mL of saline solution orally, and the infected group (IG) (n = 15) inoculated with 1 mL of saline solution containing 500 oocysts of M-49 T. gondii strain orally. After 36 d of infection, the rats were euthanized. Infection with T. gondii was confirmed by blood samples collected from all rats at the beginning and end of the experiment. The jejunum of five animals was removed and submitted to routine histological processing (paraffin) for analysis of external muscle thickness. The remaining jejunum from the others animals was used to analyze the general population and the NADH-diaphorase, VIPergic and nitrergic subpopulations of myenteric neurons; and the enteric glial cells (S100-IR). RESULTS Serological analysis showed that animals from the IG were infected with the parasite. Hypertrophy affecting jejunal muscle thickness was observed in the IG rats (77.02 ± 42.71) in relation to the CG (51.40 ± 12.34), P < 0.05. In addition, 31.2% of the total number of myenteric neurons died (CG: 39839.3 ± 5362.3; IG: 26766.6 ± 2177.6; P < 0.05); hyperplasia of nitrergic myenteric neurons was observed (CG: 7959.0 ± 1290.4; IG: 10893.0 ± 1156.3; P < 0.05); general hypertrophy of the cell body in the remaining myenteric neurons was noted [CG: 232.5 (187.2-286.0); IG: 248.2 (204.4-293.0); P < 0.05]; hypertrophy of the smallest varicosities containing VIP neurotransmitter was seen (CG: 0.46 ± 0.10; IG: 0.80 ± 0.16; P < 0.05) and a reduction of 25.3% in enteric glia cells (CG: 12.64 ± 1.27; IG: 10.09 ± 2.10; P < 0.05) was observed in the infected rats. CONCLUSION It was concluded that infection with oocysts of ME-49 T. gondii strain caused quantitative and plastic alterations in the myenteric plexus of the jejunum in rats.

Intraepithelial lymphocytes, goblet cells and VIP‐IR submucosal neurons of jejunum rats infected with Toxoplasma gondii

Toxoplasma gondii (T. gondii) crosses the intestinal barrier in oral infections and can lead to changes in different cell types, including the neurons located there. In the gastrointestinal system, the autonomous nervous system component that regulate blood flow and mucous secretion is the submucosal plexus. The aim of this study was to examine the effects of T. gondii infection on intraepithelial lymphocytes (IELs), goblet cells and submucosal neurons that are immunoreactive to vasoactive intestinal peptide (VIP‐IR) of rat jejunum. Twenty male rats distributed as a control group (CG) and an infected group (IG), which received a suspension with 500 parasite oocysts (strain ME‐49, genotype II) orally, were assessed. Routine histological sections were used to quantify IELs and to detect mucins secreted by goblet cells. Whole mounts including the submucosal layer were examined using immunofluorescence to detect the VIP neurotransmitter. Quantitative alterations in IELs were not observed. However, the reduction (P < 0.05) in the number of goblet cells that produce neutral mucins (PAS+) and sulphomucins (AB pH 1.0) and the maintenance of sialomucin‐secreting cells (AB pH 2.5) resulting in a more fluid mucous were observed. Concerning the VIP‐IR submucosal neurons, an increase in fluorescence on IG animals was observed. There was a reduction (P < 0.05) in the number of VIP‐IR submucosal neurons and atrophy of their cell bodies in IG rats. Infection with T. gondii caused alterations in the chemical composition of the intestinal mucous and reduction in the neuron number and atrophy of the remaining neurons in this cell subpopulation.

Oral dependent-dose toxoplasmic infection model induced by oocysts in rats: Myenteric plexus and jejunal wall changes

Toxoplasmosis is a widely distributed disease caused by the protozoan Toxoplasma gondii that is mainly transmitted orally. Once ingested, the parasite crosses the intestinal barrier to reach the blood and lymph systems to migrate to other regions of the host. The objective of this study was to evaluate the changes in the myenteric plexus and the jejunal wall of Wistar rats caused by oral infection with T. gondii oocysts (ME-49 strain). Inocula of 10, 100, 500 and 5000 oocysts were used. The total population of myenteric neurons and the most metabolically active subpopulation (NADH-diaphorase positive - NADH-dp) exhibited a decrease proportional to the dose of T. gondii. There was also a quantitative increase in the subpopulation of NADPH-diaphorase-positive (NADPH-dp) myenteric neurons, indicating greater expression of the NOS enzyme. Neuronal atrophy was observed, and morphological and morphometric alterations such as jejunal atrophy were found in the infected groups. Hypertrophy of the external muscle with the presence of inflammatory foci was observed in the group infected with 5000 oocysts. The changes observed in the infected groups were proportional to the number of oocysts inoculated.

Chronic infection with Toxoplasma gondii induces death of submucosal enteric neurons and damage in the colonic mucosa of rats.

Intestinal epithelial secretion is coordinated by the submucosal plexus (SMP). Chemical mediators from SMP regulate the immunobiological response and direct actions against infectious agents. Toxoplasma gondii is a worldwide parasite that causes toxoplasmosis. This study aimed to determine the effects of chronic infection with T. gondii on the morphometry of the mucosa and the submucosal enteric neurons in the proximal colon of rats. Male adult rats were distributed into a control group (n = 10) and an infected group (n = 10). Infected rats received orally 500 oocysts of T. gondii (ME-49). After 36 days, the rats were euthanized and samples of the proximal colon were processed for histology to evaluate mucosal thickness in sections. Whole mounts were stained with methylene blue and subjected to immunohistochemistry to detect vasoactive intestinal polypeptide. The total number of submucosal neurons decreased by 16.20%. Vasoactive intestinal polypeptide-immunoreactive neurons increased by 26.95%. Intraepithelial lymphocytes increased by 62.86% and sulfomucin-producing goblet cells decreased by 22.87%. Crypt depth was greater by 43.02%. It was concluded that chronic infection with T. gondii induced death and hypertrophy in the remaining submucosal enteric neurons and damage to the colonic mucosa of rats.

Toxoplasma gondii infection causes structural changes in the jejunum of rats infected with different inoculum doses

Aim: To evaluate the mucosal tunic and submucosal plexus of the jejunum of rats infected with different inoculum doses of Toxoplasma gondii. Main methods: Rats were infected with different inoculum doses (50, 500, 1000 and 5000 oocysts) of the T. gondii for 30 days, while a control group (CG) received saline solution. Blood and feces were collected before euthanasia for analysis of blood and fecal leukocytes (LEs). Histological analysis of the mucosa, submucosa, villi, crypts and enterocytes were performed. Goblet cells, intraepithelial lymphocytes (IELs) and Paneth cells were quantified. Immunohistochemistry was used to assess enteroendocrine serotonergic (5HT‐IR) cells, proliferative cells (PCNA+) and mast cells. Whole mounts were obtained to determine the total submucosal neurons by Giemsa staining and metabolically active neurons (NADH‐d+), nitrergic neurons (NADPH‐d+) and glial cells (S100). Key findings: An increase in blood LEs was observed 30 days post‐infection (dpi). Fecal LEs were more abundant in the feces in all infected groups at 21 dpi when compared to the CG. The number of IELs, sulfomucin‐producing goblet cells, Paneth cells, PCNA+ cells and mast cells increased, whereas the number of 5HT‐IR cells decreased. The jejunal architecture was altered, with atrophy of the mucosa, submucosa, villi and crypts. The number of total submucosal neurons decreased, but the NADPH‐d+ subpopulation increased. Significance: The results show how chronic toxoplasmic infection affects the tissue and cellular composition of the rat jejunum. These structural changes tend to intensify with the inoculum dose, demonstrating the importance of the parasitic load on intestinal alterations. Graphical abstract Figure. No Caption available.

Immunocompetent host develops mild intestinal inflammation in acute infection with Toxoplasma gondii

Toxoplasma gondii (T. gondii) is the causative agent of toxoplasmosis, common zoonosis among vertebrates and high incidence worldwide. During the infection, the parasite needs to transpose the intestinal barrier to spread throughout the body, which may be a trigger for an inflammatory reaction. This work evaluated the inflammatory alterations of early T. gondii infection in peripheral blood cells, in the mesenteric microcirculation, and small intestinal tissue by measurement of MPO (myeloperoxidase) activity and NO (nitric oxide) level in rats. Animals were randomly assigned into control group (CG) that received saline orally and groups infected with 5,000 oocysts for 6 (G6), 12 (G12), 24 (G24), 48 (G48) and 72 hours (G72). Blood samples were collected for total and differential leukocyte count. Intravital microscopy was performed in the mesentery to evaluate rolling and adhesion of leukocytes. After euthanasia, 0.5cm of the duodenum, jejunum and ileum were collected for the determination of MPO activity, NO level and PCR to identify the parasite DNA and also the mesentery were collected to perform immunohistochemistry on frozen sections to quantify adhesion molecules ICAM-1, PECAM-1 and P-Selectin. The parasite DNA was identified in all infected groups and there was an increase in leukocytes in the peripheral blood and in expression of ICAM-1 and PECAM-1 in G6 and G12, however, the expression of P-selectin was reduced in G12. Leukocytes are in rolling process during the first 12 hours and they are adhered at 24 hours post-infection. The activity of MPO increased in the duodenum at 12 hours, and NO increased in the jejunum in G72 and ileum in G24, G48 and G72. Our study demonstrated that T. gondii initiates the infection precociously (at 6 hours) leading to a systemic activation of innate immune response resulting in mild inflammation in a less susceptible experimental model.

Insights of Leishmania (Viannia) braziliensis infection in golden hamster (Mesocricetus auratus) intestine

AIM The present study compared and evaluated morphological and quantitative alterations in the ileum of hamsters infected by two L. (V.) braziliensis strains isolated from patients with different lesion aspects and treatment responses. MAIN METHODS Hamsters were infected in the left hindpaw with a suspension of promastigotes (2 × 107/100 μl) of two different strains of L. (V.) braziliensis. After 90 or 120 days, the animals were euthanized. Samples of the ileum and mesenteric lymph node were collected for histological examination and quantitative polymerase chain reaction. KEY FINDINGS All infected animals developed similar profile of paw lesions. In peripheral blood there was an increase in the number of mononuclear cells which contributed to elevated global leukocytes count. Increases in the width and height of villi and width and depth of crypts were observed. The thickness of the muscular layers, submucosa, and intestinal wall also increased. Histopathological alterations were observed, including inflammatory infiltrate in crypts and a large number of immune cells in the lamina propria, submucosa, and muscular layer. Immune cells were found inside myenteric ganglia, with an increase in the number of intraepithelial lymphocytes. Leishmania DNA was detected in the ileum and mesenteric lymph node at both times of infection. The presence of amastigotes in the ileum was revealed by immunohistochemistry. SIGNIFICANCE The infection with different strains of L. (V.) braziliensis causes morphological and quantitative alterations in the ileum of hamsters and the parasite can migrate to the mesenteric lymph node and intestine.

Acute infection with an avirulent strain of Toxoplasma gondii causes decreasing and atrophy of nitrergic myenteric neurons of rats

In the enteric nervous system (ENS), nitrergic neurons produce and use nitric oxide (NO) as an inhibitory motor neurotransmitter in response to parasitic infections, including those caused by Toxoplasma gondii. However, damage to the host caused by NO has been reported by various authors, and the role of NO in protection or cytotoxicity continues to be extensively studied. In this study, nitrergic neurons were investigated in the myenteric plexus of the jejunum and the distal colon of rats infected with 500 oocysts of the M7741 strain of T. gondii. Ten rats were randomly assigned into a control group (CG) and infected group (IG; received 500 sporulated oocysts of T. gondii orally). After 24h, the rats were euthanized, and samples of the jejunum and distal colon were obtained and processed for NADPH-diaphorase histochemical analysis. Quantitative and morphometric analysis of the nitrergic neurons in whole mounts containing the myenteric plexus was performed. There was a numeric reduction of nitrergic neurons per mm2 in both jejunum and distal colon. The remaining nitrergic neurons suffered atrophy in the areas of the cell body and nucleus, which resulted in a decrease in cytoplasm. Thus, we conclude that an avirulent strain of T. gondii in a short time causes neuroplastic changes in the small and large intestine of rats.

Neuronal Hypertrophy in Rat Colon Caused by Protein Deficiency

The effects of different protein levels associated with vitamin deprivation have been evaluated on tissues of high and low cell renewal. This study aimed to investigate the effects of available diet with 4% protein content associated with the maintenance of vitamin levels on the morphology of NADPH dp+ myenteric neurons of rats descending colon. Sixteen animals were randomly distributed into two groups, one that was fed with chow with 26% protein content (CG), and the other was fed with a 4% protein content diet (EG) during 12 weeks. Total preparations were used to make the myenteric plexus neurons of the descending colon evident when submitted to NADPH-diaphorase. The cellular bodies and nucleus of 300 neurons from each animal was measured. The diet with 4% protein and maintenance of vitamin and mineral content, similar to the ones found in normal protein diets, causes metabolic alterations that result in body weight loss. The myenteric neurons of the descending colon have non-significant reduction in the nucleus size whereas the cytoplasm presents a significant increase of the area. The importance of vitamin maintenance and the increase of the neuronal area are discussed as a possible compensating mechanism to keep neurotransmitter synthesis. Corresponding author: Marcelo Biondaro Gois, Department of Morphological Sciences, State University of Maringa, street: Jose Barao Neto, number 526; Maringa, Parana, Brazil, Zip code: 87080-030, Tel: +55 44 9958-0392; E-mail: marcelobiondaro@gmail.com Received Date: Nov 18, 2014 Accepted Date: Nov 25, 2014 Published Date: Nov 28, 2014 Citation: Gois, M.B., et al. Neuronal Hypertrophy in Rat Colon Caused by Protein Deficiency (2014) J Food Nutr Sci 1(1): 1-4. Int J Food Nutr Sci | Volume 1: Issue 2 www.ommegaonline.com