Reflux Esophagitis Model

Indication / Application

Preclinical screening and efficacy testing of novel acid-suppressive and mucosal protectant drugs, validation of anti-reflux surgical or endoscopic medical devices, evaluation of anti-inflammatory agents targeting esophageal tissue, and mechanistic studies on the progression from esophagitis to Barrett's esophagus.

Modeling Method

1. Surgical Chronic Reflux Platforms (Translational Models):

• Gastroduodenal Reflux Model (Mixed Reflux): Under high-magnification microsurgery, a partial pyloric ligation is performed paired with a longitudinal anterior anterior myotomy (or a surgical esophagoduodenostomy anastomosis). This surgical setup systematically forces a highly erosive mixture of gastric acid, pepsin, and duodenal bile salts retrograde into the lower esophagus.

• Acute Pyloric Ligation Model (Shay Rat Method): Temporary ligation of the pylorus is performed to accumulate aggressive gastric secretions, driving rapid, predictable acute acid reflux esophagitis within a 6 to 24-hour window.

2. Chemical / Perfusion Endoluminal Platforms:

• Direct luminal micro-perfusion or gavage of calibrated damaging solutions (such as exogenously combined hydrochloric acid and pepsin, or bile acid solutions) into the lower esophagus to evaluate acute barrier breakdown and therapeutic coating persistence.

Clinical Relevance

• Pathological Homology: The surgical models flawlessly mirror human erosive esophagitis pathology. The chronic exposure to mixed gastroduodenal reflux drives a highly realistic sequence of events: mucosal desquamation, prominent basal cell hyperplasia, and eventual elongation of lamina propria papillae.

• Device & Structural Scaling: For advanced medical device pipelines, our large-animal (porcine) surgical models provide human-scale Lower Esophageal Sphincter (LES) anatomy and realistic luminal diameter/pressures, delivering robust translation data essential for global regulatory submissions (FDA, NMPA, CE).

Key Evaluation Endpoints

1. In Vivo / Longitudinal Monitoring

• High-Resolution Micro-Endoscopy: Direct endoluminal visualization and scoring of esophageal mucosal hyperemia, erosive streaks, stricture development, and ulcerations.

• Esophageal pH & Impedance Monitoring: Real-time, continuous tracking of intraluminal pH drops and changes in mucosal baseline impedance to verify reflux severity.

• Symptom & Body Mass Indexing: Tracking of animal dietary behavior, fluid intake changes, and body weight kinetics.

2. Macroscopic & Histopathology

• Gross Lesion Indexing: Ex vivo evaluation of the lower esophagus to calculate total lesion area and establish macroscopic esophagitis scores.

• Histomorphological Assessment: Standard H&E staining to quantify tissue damage depth, mucosal thickness, basal layer hyperplasia, and perivascular inflammatory cell (neutrophil/eosinophil) infiltration.

• Mucosal Barrier Integrity Profiling: Special staining and IHC tracking for tight junction proteins (such as Claudin-1, Occludin, and ZO-1) to evaluate the preservation or recovery of the physical epithelial barrier.

3. Molecular & Inflammatory Biomarkers

• Inflammatory Cascade Quantitation: Measurement of localized tissue and systemic expression of key pro-inflammatory cytokines via RT-qPCR or Western Blot.

• Oxidative Stress Assays: Tracking of tissue Malondialdehyde (MDA) accumulation and Superoxide Dismutase (SOD) depletion to evaluate reflux-induced oxidative tissue damage.