Comparative morphological and histological characterization of palatal mucosa in rodent models: structural divergences among rats (Rattus Norvegicus), mice (Mus musculus), and hamsters (Cricetus cricetus)

The present study aimed to compare the anatomical, morphological, and histological characteristics of the palatal mucosa in three rodent species: rats, mice, and hamsters. Macroscopic and microscopic investigations, including scanning electron microscopy (SEM), were conducted on the palate tissues of the three species. Additionally, haematoxylin and eosin staining (H&E), along with Periodic Acid–Schiff staining (PAS), were performed for histological analysis. All species displayed a thick longitudinal mucosal fold in the rostral part. The palatine raphe extended the full length of the hard palate in rats but was absent in the caudal region of mice and hamsters. Rats had six palatine ridges in total: three in the middle and three in the caudal region. Mice presented three middle and four caudal palatine ridges, while hamsters had four middle and three caudal ridges. A crescent-shaped structure separates the hard and soft palates in rats. SEM revealed transverse folds and gland openings in the soft palate across all species, with additional gland openings in the caudal hard palate of hamsters. Histologically, the epithelium of both hard and soft palates was parakeratinized stratified squamous, supported by dense connective tissue. Skeletal muscles were observed in the rostral and caudal palates of rats. Glandular structures were restricted to the caudal hard palate in hamsters, and PAS-positive salivary glands were found in the soft palate of all species. Rats revealed distinct palatal morphology compared to mice and hamsters, which showed closer resemblance. These findings contribute to a better understanding of interspecies anatomical differences and have implications in comparative anatomy and biomedical applications.