[Effect of chronic restraint stress on esophageal epithelial barrier function: experiment with rats]

To investigate the effect of chronic restraint stress (CRS) on the esophageal epithelial barrier function and discuss the role of emotional factors in the pathogenesis of gastroesophageal reflux.

Twenty-four male SD rats were randomly divided into 4 equal groups: CRS group submitted to partial restraint stress 2 h per day for 7 days, CRS + acid/pepsin perfusion group submitted to partial restraint stress 2 h per day for 7 days and then anesthetization and perfusion of hydrochloric acid (pH=2) and pepsin (1 g/L) into the distal esophagus at the speed of 4 ml/h for 60 min, acid/pepsin perfusion group submitted to acid/pepsin perfusion into the esophagus, and control group. Then the rats were killed to collect the specimens of distal esophagus to undergo HE staining and light microscopy. Histological scoring was conducted. The diameter of intercellular spaces of esophageal epithelium was assessed.

The amounts of food intake and body weight increment of the CRS and CRS + acid/pepsin perfusion groups were significantly lower than those of the control and acid/pepsin perfusion groups (all P < 0.01). The histological score of the CRS + acid/pepsin perfusion group was the highest. The diameter of intercellular spaces of esophagus of the CRS + acid/pepsin perfusion group was (0.516 +/- 0.010) microm, significantly greater than those of the CRS, acid/pepsin perfusion, and control groups [(0.457 +/- 0.031) microm, (0.441 +/- 0.021) microm, and (0.235 +/- 0.027) microm respectively, P < 0.01 or P < 0.05]. The histological score of the CRS + acid/pepsin perfusion group was 2.33 +/- 0.33, significantly higher than those of the CRS, acid/ pepsin perfusion, and control groups (1.17 +/- 0.31, 1.33 +/- 0.33; and 0.33 +/- 0.21 respectively, P < 0.05 or P < 0.01).

CRS enlarges significantly the esophageal DIS and impairs the epithelial barrier function of the esophagus. Psychological factors induce or enhance the reflux symptom in the GERD patients, especially in non-erosive reflux disease and functional heartburn patients.