Toxoplasma gondii infection causes morphological changes in caecal myenteric neurons.
The aim of this study was to evaluate the effects of chronic infection of Toxoplasma gondii (with genotype I and genotype III strains) on the population density and morphometry of caecal myenteric neurons in rats. Fifteen, 60-day-old, male Wistar rats (Rattus norvegicus) were used. The animals were assigned into three groups: Control Group (CG), Experimental Group 1 (EG1) and Experimental Group 2 (EG2). EG1 animals received 10(5) tachyzoites of the genotype I (BTU IV) T. gondii strain orally, and the EG2 animals received 10(5) tachyzoites of the genotype III (BTU II) strain orally. Thirty days after inoculation, caecal whole-mount preparations were stained by Giemsa technique. The caecal preparations were then analysed by assessing the population density and morphometry of myenteric neurons in specific regions of the caecum: mesenteric apical (MA), antimesenteric apical (AA), antimesenteric basal (AB) and next to caecal ampulla (NA). Myenteric neurons from the AA region were more clustered in EG1 animals (P<0.05). The EG1 animals presented a 16.8% reduction in the area of the nucleus, whereas the EG2 animals showed 18.4% increase (P<0.05). There was a more marked reduction in the cytoplasm of the animals in EG1 (↓23.2%) compared to EG2 (↓6.2%). There was 35.8% neuronal atrophy in the AB region and 16.8% in the region NA of the EG1 animals (P<0.05). In conclusion, different strains of T. gondii cause morphometric changes in caecal myenteric neurons of rats. Only the genotype I strain was able to cause neuronal density changes.
Mestrado em Ciência Animal, Universidade Paranaense, Umuarama, Paraná, Brazil.
Larissa Marchi
LM
Zaniolo
Aristeu Vieira
AV
da Silva
Débora de Mello Gonçales
Dde M
Sant'Ana
Eduardo José de Almeida
EJ
Araújo
D000818:Animals; D001284:Atrophy; D002432:Cecum / Q000294:innervation* / Q000469:parasitology / Q000473:pathology; D002452:Cell Count; D002467:Cell Nucleus / Q000473:pathology; D003593:Cytoplasm / Q000473:pathology; D008297:Male; D009197:Myenteric Plexus / Q000166:cytology; D009474:Neurons / Q000469:parasitology / Q000473:pathology*; D011897:Random Allocation; D051381:Rats; D017208:Rats, Wistar; D014122:Toxoplasma / Q000502:physiology*; D014124:Toxoplasmosis, Animal / Q000473:pathology*