Destruction of the Dorsal Motor Nucleus of the Vagus Aggravates Inflammation and Injury from Acid-Induced Acute Esophagitis in a Rat Model

Abstract

Background/Aims. The aim of this study is to examine the protective effect of the cholinergic anti-inflammatory pathway (CAP) in experimental esophagitis in rats. Methods. A total of 40 male Sprague-Dawley (SD) rats were randomly divided into five groups as follows: control group, sham + saline group, sham + acid group, operation + saline group, and operation + acid group. Two weeks after the dorsal motor nucleus of the vagus (DMV) destruction, hydrochloric acid with pepsin was perfused into the lower part of the esophagus for 90 min. The rats were sacrificed 60 min after perfusion. The esophagus was prepared for hematoxylin and eosin (HE) staining, and the degree of inflammation and NF-κB activation in the esophagus was measured. Inflammatory cytokines (TNF-α, IL-6, IL-1β, and PGE2) in the esophagus were measured by ELISA. The brain was removed and processed for c-fos immunohistochemistry staining. The c-fos-positive neurons were counted and analyzed. Results. The TNF-α, IL-1β, IL-6, and PGE2 concentrations in the esophageal tissue increased after acid perfusion. The microscopic esophagitis scores and the activation of NF-κB p65 in the esophagus were significantly higher in the operation + acid group than in the operation + saline group. c-fos-positive neurons significantly increased in rats receiving acid perfusion in the amygdala (AM), the paraventricular nucleus of the hypothalamus (PVN), the parabrachial nucleus (PBN), the nucleus of the solitary tract (NTS)/DMV, the nucleus ambiguous (NA), the reticular nucleus of the medulla (RNM), and the area postrema (AP). After DMV destruction, c-fos expression was reduced in the AM, PVN, PBN, NTS/DMV, NA, RNM, and AP, especially in the AM, PVN, NTS/DMV, RNM, and AP. Conclusions. The DMV is an important nucleus of the CAP. The DMV lesion can aggravate esophageal inflammation and injury from acid-induced acute esophagitis in a rat model. The CAP has a protective effect on the acute esophagitis rat model and could be a new therapy for reflux esophagitis (RE).