Tail clamping induces anxiety-like behaviors and visceral hypersensitivity in rat models of non-erosive reflux disease.

BACKGROUND: Non-erosive reflux disease (NERD), the main gastroesophageal reflux subtype, features reflux symptoms without mucosal damage. Anxiety links to visceral hypersensitivity in NERD, yet mechanisms and animal models are unclear. AIM: To establish a translational NERD rat model with anxiety comorbidity via tail clamping and study corticotropin-releasing hormone (CRH)-mediated neuroimmune pathways in visceral hypersensitivity and esophageal injury. METHODS: Sprague-Dawley (SD) and Wistar rats were grouped into sham, model, and modified groups (n = 10 each). The treatments for the modified groups were as follows: SD rats received ovalbumin/aluminum hydroxide suspension + acid perfusion ± tail clamping (40 minutes/day for 7 days), while Wistar rats received fructose water + tail clamping. Esophageal pathology, visceral sensitivity, and behavior were assessed. Serum CRH, calcitonin gene-related peptide (CGRP), 5-hydroxytryptamine (5-HT), and mast cell tryptase (MCT) and central amygdala (CeA) CRH mRNA were measured via ELISA and qRT-PCR. RESULTS: Tail clamping induced anxiety, worsening visceral hypersensitivity (lower abdominal withdrawal reflex thresholds, P < 0.05) and esophageal injury (dilated intercellular spaces and mitochondrial edema). Both models showed raised serum CRH, CGRP, 5-HT, and MCT (P < 0.01) and CeA CRH mRNA expression (P < 0.01). Behavioral tests confirmed anxiety-like phenotypes. NERD-anxiety rats showed clinical-like symptom severity without erosion. CONCLUSION: Tail clamping induces anxiety in NERD models, worsening visceral hypersensitivity via CRH neuroimmune dysregulation, offering a translational model and highlighting CRH as a treatment target.