Alterations induced in the ileum of mice upon inoculation with different species of Leishmania: a preliminary study

INTRODUCTION

Leishmania species cause skin, mucosal, and disseminated lesions. We studied the effects of three Leishmania species on ileal morphology in mice.

METHODS

BALB/c mice were intraperitoneally inoculated with Leishmania (Leishmania) amazonensis, Leishmania (Viannia) braziliensis, and Leishmania (Leishmania) major (4 animals/group). After 72h, the ilea were collected and histologically processed.

RESULTS

Following inoculation, the goblet cell and intraepithelial lymphocyte populations increased, while Paneth cell number and crypt width decreased. In addition, enterocyte size, villi height, and mucosa, submucosa, and muscular tunic thickness increased.

CONCLUSIONS

Leishmania modified the quantity of cells in and morphology of mice ilea.

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.

Comparative study of effects of assemblages AII and BIV of Giardia duodenalis on mucosa and microbiota of the small intestine in mice

AIMS

Giardiasis is one of the major causes of diarrhea worldwide and its symptoms vary in intensity, which can be attributed to different parasite assemblages. The goal of the present study was to compare the effects of infection caused by assemblages AII and BIV ofGiardia duodenalis on the response of the small intestine, microbiota, and behavioral parameters in mice.

MAIN METHODS

Swiss mice were infected with assemblages AII and BIV of G. duodenalis for 15 days. Leucometry, pain, intestinal microbiota and histological parameters of the duodenum and jejunum were evaluated in the experimental groups.

KEY FINDINGS

Both assemblages modified the composition of the intestinal microbiota. Infection with assemblage AII promoted leukocytosis, reflected by increasing number of polymorphonuclear cells, intraepithelial lymphocytes and pain-related behavior, indicating that this was the more aggressive assemblage with regard to its effects on the intestinal mucosa and duodenum.

SIGNIFICANCE

The specific assemblage of the parasite is an important parameter that affects symptomatology in the host.

Different inoculum loads of Toxoplasma gondii induce reduction of myenteric neurons of the rat colon

Abstract Toxoplasmosis, a disease caused by Toxoplasma gondii, is an important health problem, especially in immunocompromised hosts. T. gondii uses the gut wall as an infection gateway, with tropism for muscular and nervous tissues causing intestinal alterations, including some in the enteric nervous system. This study aims at investigating the colon of rats infected by T. gondii in order to understand how the amount of oocysts influences in myenteric neuronal changes. Sixty Wistar rats (Rattus norvegicus) were divided into six groups. One group remained as a control and the others received inocula of 10, 50, 100, 500 or 5,000 oocysts of T. gondii. The animals were euthanized after 30 days of infection. The total neuronal population and the nitrergic subpopulation in the colon myenteric plexus of each animal was counted. The data were statistically analyzed showing less weight gain in rats with 10, 500 and 5,000 oocysts. A decrease in the number of total neurons with 50, 100 or 5,000 oocysts and an increase in the nitrergic population with 10, 100, 500 or 5,000 oocysts were verified. These results show that neuronal alterations are more significant when the infection is induced by larger inocula and reinforces the suspicion that neuronal loss is directed at cholinergic neurons.

Kinetics of acute infection with Toxoplasma gondii and histopathological changes in the duodenum of rats

Toxoplasma gondii crosses the intestinal barrier to spread into the body. We investigate the intestinal wall and epithelial cells of the duodenum of rats infected with T. gondii during different time points of acute infection. Male Wistar rats, 60 days of age, were assigned into groups that were orally inoculated with 5000 sporulated oocysts T. gondii for 6 h (G6), 12 h (G12), 24 h (G24), 48 h (G48), 72 h (G72), 7 days (G7d), and 10 days (G10d). The control group (CG) received saline. The rats were killed and the duodenum was processed to obtain histological sections stained with hematoxylin and eosin, Periodic Acid Schiff, and Alcian blue (pH 2.5 and 1.0). Morphometry was performed on the layers of the intestinal wall and enterocytes, and the number of goblet cells and intraepithelial lymphocytes was counted. The data were compared by ANOVA considering 5% as level of significance. The infection provoked an increase in the width of villi and crypts; decrease in enterocyte height; increase in the smaller-diameter and reduction in the larger-diameter of the enterocytes nuclei, increased number of goblet cells secreting neutral (G6, G12 and G7d) and acidic (G7d and G10d) mucus, and increase in the number of intraepithelial lymphocytes (G48). The infected groups showed atrophy of the submucosa and muscular layers and the total wall. Acute infection with T. gondii caused morphological changes in the intestinal wall and epithelial cells of the duodenum in rats.