title: Intestinal and neuronal myenteric adaptations in the small intestine induced by a high-fat diet in mice.
abstract: BACKGROUND
  The prevalence of obesity has increased at alarming rates, particularly because of the increased consumption of high-fat diets (HFDs). The influence of HFDs on intrinsic innervation and the intestinal wall has not been fully characterized. The aim of this study was to investigate the morpho-quantitative aspects of myenteric neurons and the wall of the small intestine in mice fed a HFD.
  
  
  METHODS
  Swiss mice were fed a HFD (59% kcal from fat) or standard chow (9% Kcal from fat) for 8 weeks. Segments of the duodenum, jejunum, and ileum were subjected to histological processing for morpho-quantitative examination of the intestinal wall and mucosal cells, and immunohistochemistry was performed to evaluate myenteric neurons. The data for each segment were compared between the groups using an unpaired Student's t-test or an equivalent nonparametric test.
  
  
  RESULTS
  The HFD increased body weight and visceral fat and decreased the length of the small intestine and the circumference of the ileum. In the duodenum, the HFD increased the density of the nitrergic subpopulation and decreased the area of nitrergic neurons and vasoactive intestinal peptide (VIP) varicosities. In the jejunum, the density of the nitrergic subpopulation was increased and the neuronal areas of the general population, nitrergic subpopulation and (VIP) varicosities were reduced. In the ileum, the density of the general population and nitrergic subpopulation were increased and the neuronal areas of the general population, nitrergic subpopulation and (VIP) varicosities were reduced. The morphometric parameters of the villi, crypts, muscular layer and total wall generally increased in the duodenum and jejunum and decreased in the ileum. In the duodenum and jejunum, the HFD promoted a decreased in the proportion of intraepithelial lymphocytes. In the ileum, the proportion of intraepithelial lymphocytes and goblet cells reduced, and the enteroendocrine cells increased.
  
  
  CONCLUSIONS
  The high-fat diet induces changes in the myenteric innervation of the small intestine, intestinal wall and mucosal cells responsible for the secretion of hormones and maintenance of the protective intestinal barrier. The morpho-quantitative data provide a basis for further studies to clarify the influence of HFD in the motility, digestive and absorptive capacity, and intestinal barrier.
authors.affiliation: Center of Medical and Pharmaceutical Sciences, State University of the West of Paraná, R. Universitária, 1619, Cascavel, PR, CEP 85819-110, Brazil. angelica.soares@gmail.com.
authors.forename: Angelica
authors.initials: A
authors.lastname: Soares
authors.affiliation: Department of Morphological Sciences, State University of Maringá, Av. Colombo, 5790, Maringá, PR, CEP 87020-900, Brazil. evandroberaldi@gmail.com.
authors.forename: Evandro José
authors.initials: EJ
authors.lastname: Beraldi
authors.affiliation: Department of Morphological Sciences, State University of Maringá, Av. Colombo, 5790, Maringá, PR, CEP 87020-900, Brazil. pb_ferreira@hotmail.com.
authors.forename: Paulo Emílio Botura
authors.initials: PE
authors.lastname: Ferreira
authors.affiliation: Department of Pharmacology and Therapeutics, State University of Maringá, Av. Colombo, 5790, Maringá, PR, CEP 87020-900, Brazil. rbbazotte@uem.br.
authors.forename: Roberto Barbosa
authors.initials: RB
authors.lastname: Bazotte
authors.affiliation: Department of Morphological Sciences, State University of Maringá, Av. Colombo, 5790, Maringá, PR, CEP 87020-900, Brazil. ncbuttow@uem.br.
authors.forename: Nilza Cristina
authors.initials: NC
authors.lastname: Buttow
mesh_terms: D000818:Animals; D049109:Cell Proliferation; D059305:Diet, High-Fat / Q000009:adverse effects*; D004386:Duodenum / Q000294:innervation / Q000473:pathology / Q000503:physiopathology; D019858:Enteroendocrine Cells; D020397:Goblet Cells; D007082:Ileum / Q000294:innervation / Q000473:pathology / Q000503:physiopathology; D007413:Intestinal Mucosa / Q000473:pathology* / Q000503:physiopathology; D007421:Intestine, Small / Q000294:innervation* / Q000473:pathology* / Q000503:physiopathology; D007583:Jejunum / Q000294:innervation / Q000473:pathology / Q000503:physiopathology; D018655:Lymphocyte Count; D008297:Male; D051379:Mice; D009197:Myenteric Plexus / Q000473:pathology; D024701:Myosin Type V / Q000032:analysis; D009474:Neurons / Q000737:chemistry* / Q000473:pathology*; D026602:Nitrergic Neurons / Q000473:pathology; D009765:Obesity / Q000209:etiology / Q000473:pathology; D014660:Vasoactive Intestinal Peptide / Q000032:analysis
chemical_list: D014660:Vasoactive Intestinal Peptide; D024701:Myosin Type V