title: Esophageal morphometric and biomechanical changes during aging in rats.
abstract: BACKGROUND
  Human studies have demonstrated aging-related changes in esophagus which may contribute to the increased rate of gastro-esophageal reflux in elderly. The aim of this study was to investigate esophageal morphometric and biomechanical remodeling in aging rats to obtain detailed information about aging-related changes.
  
  
  METHODS
  Twenty-four male Wistar rats, aged from 6 to 22 months, were studied. Morphometric data were obtained by measuring the wall thickness and cross-sectional area. The esophageal diameter and length were obtained from digitized images of the segments at preselected luminal pressure levels and at no-load and zero-stress states. Circumferential and longitudinal stresses (force per area) and strains (deformation) were computed from the length, diameter and pressure data, and from the zero-stress state geometry.
  
  
  RESULTS
  The esophageal parameters such as the weight per unit length, the wall thickness and the wall cross-sectional area increased slightly from 6 to 22 months (p < 0.05 to p < 0.001). The opening angle gradually decreased during aging (p < 0.05). The interface between the mucosa-submucosa and muscle layers slightly moved outwards and the neutral axis moved inwards during aging. The stress-strain data showed that the esophageal wall became stiffer circumferentially and longitudinally during aging (p < 0.05, p < 0.01). However, the circumferential wall stiffness showed no further change after 12 months.
  
  
  CONCLUSIONS
  A pronounced morphometric and biomechanical remodeling occurred in the rat esophagus during aging.
authors: Giome Academia, Department of Clinical Medicine, Aarhus University, Aarhus, Denmark.|GIOME and the Key Laboratory for Biorheological Science and Technology of Ministry of Education, Bioengineering College of Chongqing University, Chongqing, China.
authors: J
authors: J
authors: Zhao
authors: GIOME and the Key Laboratory for Biorheological Science and Technology of Ministry of Education, Bioengineering College of Chongqing University, Chongqing, China.
authors: H
authors: http://orcid.org/0000-0002-5792-2845
authors: H
authors: Gregersen
mesh_terms: D000375:Aging / Q000473:pathology* / Q000502:physiology*; D000818:Animals; D001696:Biomechanical Phenomena; D004947:Esophagus / Q000473:pathology* / Q000503:physiopathology*; D008297:Male; D051381:Rats; D017208:Rats, Wistar; D013314:Stress, Mechanical
keywords: aging; esophagus; morphometry; opening angle; residual strain; stress-strain