Toxoplasma gondii Induces Death of Gastric Myenteric Neurons in Rats

Abstract

SUMMARY:The aim of the study was quantifying and morphologically analyzing the myenteric neurons of the small and large gastric curvatures of the glandular stomach of rats infected the tachyzoites of the Toxoplasma gondii for 30 days. Ten male rats were assigned into two groups: Control Group (CG) and Experimental Group (EG). The animals from the CG received saline solution orally whereas the EG animals received 104 tachyzoites of the T. gondii genotype III strain (BTU II). After 30 days, euthanasia was conducted for the removal of the stomach, which was dissected under the stereomicroscope for removal of the tunica mucosa and the tela submucosa. Whole mounts were stained with Giemsa. Quantification of the myenteric neurons was conducted by using a 40X-objective microscope in 40 microscopic fields for the region of the small gastric curvature and 40 fields for the large gastric curvature of the glandular stomach of the animals from both groups. The cell body of 50 myenteric neurons from each region was measured for each animal. Chronic experimental infection caused by the genotype III strain of Toxoplasma gondii was verified to reduce myenteric neuron density only in the small gastric curvature region of the glandular stomach, not resulting in significant changes in the size of the neurons.

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

“…Reduction in the total population of myenteric neurons was observed in previous studies from our group in the duodenum of birds (1000 oocysts -M7741 (Bonapaz et al, 2010)) and in the stomach of rats (500 oocysts -M7741 (Alves et al, 2011)). However, in other studies that used different inocula, strains and organs, no quantitative changes in the enteric nervous system were observed (Hermes-Uliana et al, 2011;Pereira et al, 2010).…”

Toxoplasma gondiicauses death and plastic alteration in the jejunal myenteric plexus

“…Myenteric neuronal death caused by toxoplasmic infection is not a common finding. Until now this phenomenon had only been observed in the duodenum of poultry [33] and the stomach of rats [11] infected by the T. gondii genotype Ⅲ…”

“…These alterations seem to be related to several factors such as genotype strain, life form and inoculation route (oral or intraperitoneal) of the parasite in addition to the infection phase (acute or chronic), digestive tract region and the type of cells assessed [5][6][7][8][9][10][11][12][13][14][15] .…”

“…In addition, components of the nervous system intrinsic to the digestive tract, the enteric nervous system (ENS), reveal signs of plasticity due to alterations induced by toxoplasmic infections in the intestinal wall. Therefore, available experimental studies carried out in rats [5][6][7][8][9][10][11][12][13][14][15] have shown that these plastic alterations depend on several factors such as strain; infectious stage (tachyzoites, bradyzoites, sporozoites) and inoculation route (oral or intraperitoneal) of the parasite; infection phase (acute or chronic) assessed; digestive tract region and group of nervous cells assessed. For instance, while chronic infection caused by tachyzoites from a genotype Ⅰ strain (for the SAG2 gene) causes atrophy of cell bodies in ileal myenteric neurons [7] , this same infection causes hypertrophy of cell bodies in colonic myenteric neurons [8] .…”

Morphoquantitative Study of Rattus norvegicus Submucosal Plexus by Different Neuronal Evidentiation Histochemical Techniques

“…ENS consists of segments from the upper esophagus until the internal anal sphincter, formed by interconnected meshes: plexuses containing neurons, axons and glial cells. In the intestines, most of the nervous cells form two ganglionated plexus: (Auerbach' s) myenteric plexus located between the longitudinal stratum and the circular muscle layer (Auerbach, 1862apud Furness, 2006Alves et al, 2011;Furness, 2012) and the submucosal plexus (Meissner, 1857apud Furness, 2006Billroth, 1858 apud Furness, 2006), formerly known as Meissner' s plexus, found in the tela submucosa of the large and small intestines (Mckeown et al, 2001;Wood, 2004;Furness, 2006;Grundy et al, 2006).…”