Structural and Ultrastructural Characteristics of the Red-Rumped Agouti (Dasyprocta leporina-Linnaeus, 1758) Palatine Epithelium

Morphological tongue and palate characterizations in Trachemys adiutrix (Vanzolini, 1995) turtles

Morphological studies on the oropharyngeal cavity of turtles are an interesting tool in understanding evolutionary processes associated with feeding habits. There is paucity of morphological information on the oropharyngeal cavity of the Trachemys adiutrix turtle. Thus, the aim of this study was to describe the tongue and palate morphology of T. adiutrix to establish a standard model for the species, providing information that may improve knowledge on the species feeding habits. Gross dissection, light microscopy and scanning electron microscopy assessments of 11 specimens were carried out. The tongue of T. adiutrix is triangular with a slightly rounded apex and broad base and lingual papillae widely distributed throughout the entire dorsal surface. The palate is composed of bony structures, displaying a triangular apex with one pair of choanae and palatine raphe that begin in the middle region, dividing the two openings. The body was elongated and smooth. The root was wrinkled and opened into the oesophagus. The tongue was lined by non-keratinized stratified squamous epithelium, rich in mucous cells and a large number of different-shaped papillae and taste buds. The palate was mainly lined by a pseudostratified cylindrical ciliated epithelium rich in mucous cells. In conclusion, the tongue and palate characteristics of T. adiutrix include evidence that these animals are semiaquatic, displaying morphological characteristics associated with aquatic and terrestrial trophic ecology, similar to that observed in other semiaquatic and terrestrial chelonian species.

Structural and Ultrastructural Characteristics of the Spix's Yellow-Toothed Cavy (Galea spixii, Wagler, 1831) Tongue

The tongue is a fundamental organ in feeding, vocalization, and grooming. It is characterized by evolutionary adaptations reflected by diet, habitat, and function. Rodents are a very diverse mammalian order and the tongue's morphology varies in size, form, and presence of papillae. This work aimed to describe the morphological and ultrastructural aspects of the tongue of Spix's yellow-toothed cavy (Galea spixii, Wagler, 1831). Tongues of Spix's yellow-toothed cavies were analyzed with light microscopy, scanning, and transmission electron microscopy. The results showed that the tongue was divided into apex, body, and root. There were different types of papillae, such as vallate, foliate, laterally placed fungiform, fungiform, filiform, and robust filiform. The epithelium was organized into layers, including keratinized, granulous, spinous, and basal, below were lamina propria, and musculature, which evolved mucous and serous gland clusters. The tongue of Spix's yellow-toothed cavy was structurally and ultrastructurally similar to other rodents and had papillae with similar morphologies to other Caviidae species. However, the presence of robust filiform papillary lines and laterally placed fungiform papillae showed the main differences from other species. This was the first description of the tongue of Spix's yellow-toothed cavy.

Structural and Ultrastructural Changes in the Tongue of mdx Mice

The mdx mouse is an experimental model of Duchenne muscular dystrophy, a genetic disorder characterized by progressive muscular degeneration which affects the oral cavity musculature, and promotes difficulty in swallowing. This study aimed to describe morphological, structural, and ultrastructural changes in the tongue mucosa and musculature of mdx mice. Forty six-month-old mice were divided into two groups: Control C57bl/10 (n = 20) and mdx C57bl/10mdx (n = 20). The tongue was dissected and analyzed with light microscopy, scanning electron microscopy, and transmission electron microscopy techniques. Our results showed conical and triangular filiform, fungiform, foliate, and vallate papillae, and their connective tissue cores. The epithelium layers identified were corneum, granulosum, spinosum, and basale. The mdx group had a thicker epithelium. Lamina propria was composed of reddish and greenish collagen. In mdx, collagen was present in the musculature of the tongue's body and in the muscular tissue between mucous and serous glands of the caudal region. Musculature was also characterized by a shorter length of sarcoplasmic invaginations, myocytolysis in mitochondrial groupings, and inflammatory focus. In conclusion, the tongue of 6-month-old mdx mice had morphology, structure, and ultrastructure revealed, showing higher wear of filiform papillae indirect reflex from the muscular degeneration process.