Avaliação morfogenética quantitativa dos plexos submucoso e mioentérico do íleo de eqüinos com aganglionose

• Autor(a) principal: Muniz, Eliane [UNIFESP]
• Data de Publicação: 2010
• Tipo de documento: Dissertação
• Idioma: por
• Título da fonte: Repositório Institucional da UNIFESP
• Texto Completo: http://repositorio.unifesp.br/handle/11600/9126
• topic: Doença de Hirschsprung; Ileo

Intestinal aganglionosis is the congenital and hereditary absence of the ganglionic neurons that form the submucosal and myenteric plexuses, a condition that consequently leads to peristaltic disorders. In humans this illness is called “Hirschsprung’s Disease” (HD) and in horses, ileocolic aganglionosis (ICA). Economic losses related to the seriousness of ICA, as well as the absence of three-dimensional quantitative studies on the morpho-functionality of the plexuses creates the need for studies that can contribute to an understanding of it. In this work, the aim was to carry out a morpho-quantitative assessment (stereological) of the submucosal and myenteric nerve plexuses of the ileums of clinically healthy foals and those suffering from ileocolic aganglionosis. The estimated stereological parameters were: volume of the ileum (Víleo), the volume density of the myenteric ganglia (VvGmio) and of the ganglia of the submucosal plexus (VvGsub), the total volume of the myenteric ganglia (VTOTGmio), the total volume of the submucosal ganglia (VTOTGsub), the volume density of the muscle tunic of the ileum (VvMUS), the submucosal tunic of the ileum (VvSUB), the mucosal tunic of the ileum (VvMUC) and the total volume of these tunics: (VTOTMUS), (VTOTSUB) and (VTOTMUC), respectively. The ileums from five healthy male foals, of indeterminate breed (control group, “CG”) and five male “paint horse” foals suffering from ICA (experimental group “EG”) were used. After the foals had been euthanized their ileums were removed and sampled using the fractionator principle. The samples were fixed (formaldehyde 4%), embedded (araldite) and sectioned (ultramicrotome). Within 18 hours of the EG foals being born they had signs of recurrent abdominal discomfort, a decrease in or absence of intestinal motility, hyporexia, tachypnea, tachycardia and tenesmus. Genetically, the EG foals were homozygotes in the PCR mutant gene analysis by SLOB. There was a reduction of 154% in the total volume of the ileum in animals suffering from ICA. In addition to this change we also identified a reduction in the total volume of the muscle, submucosal and mucosal tunics by around 207%, 285% and 280% respectively. The volume density of the myenteric ganglion of the ICA group was also drastically reduced by some 16 times. The total volume occupied by these ganglia in the ileum of the horses was also reduced by 42 times. ICA caused the following alterations in the structure of the ileum of the horses: (i) atrophy of the mucosal, submucosal and muscle tunics; (ii) atrophy of the neurons of the myenteric and submucosal plexuses; (iii) hypoplasia of the neurons of the myenteric and submucosal plexuses (iv) atrophy of the total volume of the ileum.