Construction of a New Laryngopharyngeal Reflux Disease Animal Model

This study aims to develop a novel endogenous laryngopharyngeal reflux disease (LPRD) rat model.

Twenty-four healthy Sprague Dawley rats were randomly divided into four groups: control group, 3-day LPRD model group (3d-LPRD), 7-day LPRD model group (7d-LPRD), and 28-day LPRD model group (28d-LPRD). After the model was established, rats were anesthetized at the corresponding time points. The model group was established by damaging the rats' gastric His angle and ligating the proximal stomach along the "limiting ridge," combined with damaging the diaphragm at the esophageal hiatus. Using a laryngoscope and H&E staining to observe the vocal cords of rats, followed by pepsin immunohistochemical staining of rat vocal cord tissue, immunofluorescence staining of cell junction proteins (E-cadherin, ZO-1), myeloperoxidase (MPO) detection, and Western blotting experiments for PI3K, Akt, and p-Akt proteins.

Compared with the control group, the LPRD model group showed inflammatory manifestations under laryngoscopy. H&E staining shows infiltration of inflammatory cells in the vocal cord tissue, with disruption of collagen fibers in the lamina propria and the presence of new capillaries. Immunohistochemical staining for pepsin in the vocal cords is positive. The immunofluorescence signals of ZO-1 and E-cadherin are weakened, and the fluorescence signals are discontinuous. MPO levels were significantly elevated (P < 0.05). Western blot analysis found that the levels of ZO-1 and E-cadherin in the LPRD model group were significantly lower than those in the control group (P < 0.05), while the levels of PI3K, Akt, and p-Akt were significantly higher than those in the control group (P < 0.05).

Successfully established a new LPRD animal model and found that pharyngeal reflux may disrupt the integrity of pharyngeal epithelial cell connections by activating the PI3K/Akt signaling pathway.