A rat model of adenoid hypertrophy constructed by using ovalbumin and lipopolysaccharides to induce allergy, chronic inflammation, and chronic intermittent hypoxia.

Abstract

Adenoid hypertrophy (AH) is a common pediatric disease that significantly impacts the growth and quality of life of children. However, there is no replicable and valid model for AH. An AH rat model was developed via comprehensive allergic sensitization, chronic inflammation induction, and chronic intermittent hypoxia (CIH). The modeling process involved three steps: female Sprague-Dawley rats (aged 4-5 weeks) were used for modeling. Allergen sensitization was induced via intraperitoneal administration and intranasal provocation using ovalbumin (OVA); chronic nasal inflammation was induced through intranasal lipopolysaccharide (LPS) administration for sustained nasal irritation; CIH akin to obstructive sleep apnea/hypopnea syndrome was induced using an animal hypoxia chamber. Postmodel establishment, behaviors, and histological changes in nasopharynx-associated lymphoid tissue (NALT) and nasal mucosa were assessed. Arterial blood gas analysis and quantification of serum and tissue levels of (interleukin) IL-4 and IL-13, OVA-specific immunoglobulin E (sIgE), eosinophil cationic protein (ECP), tumor necrosis factor (TNF-α), IL-17, and transforming growth factor (TGF)-β were conducted for assessment. The treatment group received a combination of mometasone furoate and montelukast sodium for a week and then was evaluated. Rats exhibited notable nasal symptoms and hypoxia after modeling. Histopathological analysis revealed NALT follicle hypertrophy and nasal mucosa inflammatory cell infiltration. Elevated IL-4, IL-13, IL-17, OVA-sIgE, ECP, and TNF-α levels and reduced TGF-β levels were observed in the serum and tissue of model-group rats. After a week of treatment, the treatment group exhibited symptom and inflammatory factor improvement. The model effectively simulates AH symptoms and pathological changes. But it should be further validated for genetic, immunological, and hormonal backgrounds in the currently used and other strains and species.