title: Toxoplasma gondii causes death and plastic alteration in the jejunal myenteric plexus.
abstract: OBJECTIVE
  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.
  
  
  CONCLUSIONS
  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.
authors.affiliation: Eduardo José de Almeida Araújo, Departamento de Histologia, Centro de Ciências Biológicas, Universidade Estadual de Londrina, 86057-970 Paraná, Brazil.
authors.forename: Eduardo José de Almeida
authors.initials: EJ
authors.lastname: Araújo
authors.affiliation: Eduardo José de Almeida Araújo, Departamento de Histologia, Centro de Ciências Biológicas, Universidade Estadual de Londrina, 86057-970 Paraná, Brazil.
authors.forename: Larissa Marchi
authors.initials: LM
authors.lastname: Zaniolo
authors.affiliation: Eduardo José de Almeida Araújo, Departamento de Histologia, Centro de Ciências Biológicas, Universidade Estadual de Londrina, 86057-970 Paraná, Brazil.
authors.forename: Suellen Laís
authors.initials: SL
authors.lastname: Vicentino
authors.affiliation: Eduardo José de Almeida Araújo, Departamento de Histologia, Centro de Ciências Biológicas, Universidade Estadual de Londrina, 86057-970 Paraná, Brazil.
authors.forename: Marcelo Biondaro
authors.initials: MB
authors.lastname: Góis
authors.affiliation: Eduardo José de Almeida Araújo, Departamento de Histologia, Centro de Ciências Biológicas, Universidade Estadual de Londrina, 86057-970 Paraná, Brazil.
authors.forename: Jacqueline Nelisis
authors.initials: JN
authors.lastname: Zanoni
authors.affiliation: Eduardo José de Almeida Araújo, Departamento de Histologia, Centro de Ciências Biológicas, Universidade Estadual de Londrina, 86057-970 Paraná, Brazil.
authors.forename: Aristeu Vieira
authors.initials: AV
authors.lastname: da Silva
authors.affiliation: Eduardo José de Almeida Araújo, Departamento de Histologia, Centro de Ciências Biológicas, Universidade Estadual de Londrina, 86057-970 Paraná, Brazil.
authors.forename: Débora de Mello Gonçales
authors.initials: Dde M
authors.lastname: Sant'Ana
mesh_terms: D000818:Animals; D015415:Biomarkers / Q000378:metabolism; D008058:Dihydrolipoamide Dehydrogenase / Q000378:metabolism; D004195:Disease Models, Animal; D007583:Jejunum / Q000294:innervation*; D008297:Male; D009130:Muscle, Smooth / Q000294:innervation*; D009197:Myenteric Plexus / Q000378:metabolism / Q000469:parasitology* / Q000503:physiopathology; D009457:Neuroglia / Q000378:metabolism / Q000469:parasitology; D009473:Neuronal Plasticity; D026602:Nitrergic Neurons / Q000378:metabolism / Q000469:parasitology; D017208:Rats, Wistar; D013997:Time Factors; D014122:Toxoplasma / Q000472:pathogenicity*; D014123:Toxoplasmosis / Q000469:parasitology* / Q000503:physiopathology; D014660:Vasoactive Intestinal Peptide / Q000378:metabolism
chemical_list: D015415:Biomarkers; D014660:Vasoactive Intestinal Peptide; D008058:Dihydrolipoamide Dehydrogenase
keywords: Enteric nervous system; Glial cells; Infectious diseases; Neuronal plasticity; Nitric oxide; Small intestine; Toxoplasmosis; Vasoactive intestinal peptide