How does reflux affect laryngeal tissue quality? An experimental and histopathologic animal study

Abstract

Objective To investigate the histopathologic changes in intact laryngeal epithelium and mucosa exposed to endogenous gastric acid and pepsin in an experimental model of reflux. Study Design Randomized trial. Setting The study was conducted at the animal care facility of Haydarpasa Numune Education and Research Hospital. Subjects and Methods Eighteen healthy 200- to 220-g, 20-week-old Sprague-Dawley rats were used. The animals were divided into three groups according to exposure time (1-, 4-, and 12-week exposures), and four rats were examined as controls who underwent sham operation. An experimental model of gastroesophageal reflux was induced. After exposure, the animals were euthanized, and their larynges were removed. The histopathologic changes in the larynx were observed under a light microscope. Results The mean scores for inflammation in the control, one-, four-, and 12-week groups were 0.75 ± 0.50, 1.75 ± 0.50, 2.20 ± 0.45, and 1.94 ± 0.87, respectively. However, mean scores for vascular engorgement in the control, one-, and four-week groups were 0, and in the 12-week group was 2.0 ± 0.70. The mean scores for subepithelial edema in the control, one-, four-, and 12-week groups were 1.00 ± 0, 1.75 ± 0.95, 1.80 ± 0.45, and 2.20 ± 0.84, respectively. However, mean scores for keratinization for the control, one-, and four-week groups were 0, and for the 12-week group was 1.60 ± 0.55. When we compared inflammation, vascular engorgement, subepithelial edema, and keratinization mean scores between the control and study groups, there were statistically significant increases ( P = 0.005, P = 0.001, P = 0.043, P = 0.002, respectively). Conclusion Our findings suggest that reflux induces significant histopathologic changes in larynx mucosa.