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

• Published in: Experimental parasitology 2015-09, Vol.156, p.12-18
• Main Authors: Vicentino-Vieira, Suellen Laís, Nogueira de Melo, Gessilda de Alcantara, Biondaro Góis, Marcelo, Martins Moreira, Neide, de Araujo Pereira, Luana Gabriela, de Almeida Araújo, Eduardo José, Garcia, João Luiz, de Mello Gonçales Sant'Ana, Débora
• Format: Article
• Language: English
• Subjects: Animals; Antibodies, Protozoan - blood; Disease Models, Animal; Enteric nervous system; Histocytochemistry; Histopathology; Immunoglobulin G - blood; Jejunum - pathology; Male; Myenteric Plexus - pathology; NAD; NADP; Neurons - pathology; Oocysts; Random Allocation; Rats; Rats, Wistar; Toxoplasma - immunology; Toxoplasma gondii; Toxoplasmosis; Toxoplasmosis, Animal - pathology; Wistar rat
• ISSN: 0014-4894; 1090-2449
• DOI: 10.1016/j.exppara.2015.05.007

•We analyzed the jejunum of rats infected with different doses of T. gondii.•The tested dose was from 10 to 5000 oocysts orally.•NADHd-p and NADPHd-p neuronal atrophy was observed.•Morphological and morphometric alterations were found in the infected groups.•Hypertrophy of the muscle was observed in the group infected with 5000 oocysts. 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.