Cytokeratin (CK) comprises the intermediate filament cytoskeleton of epithelial cells. Patterns of CK expression can be regarded as a specific marker for epithelial differentiation status. The aim of this study was to identify CK expression on tongues of Korean native goats ranging from 60-day-old fetuses to newborns during prenatal development using immunohistochemistry. The tongues of fetuses were removed from 2- to 4-year-old female Korean native goats by caesarean section performed under general anesthesia. Immunohistochemistry was performed to assess CK expression patterns on developing goat tongues using serial paraffin-embedded sections. Light zones signifying CK immunoreactivity in dorsal lingual epithelia were weakly positive in 60-day-old fetuses. In 90-day-old fetuses, deep areas in dorsal lingual epithelia were strongly positive for CK expression and superficial areas were moderately positive. In 120-day-old fetuses, light zones of lingual epithelia in the vallate papilla were strongly positive for CK expression, whereas ducts of von Ebner’s glands were moderately positive. In neonates, taste buds were positive for CK expression, whereas non-taste epithelial cells and von Ebner’s glands were negative. These findings indicate that goat tongues have different patterns of CK expression during development and provide a morphological basis for studies on the biological mechanism of epithelial differentiation.

The purpose of this study was to identify the composition and organization of lingual tissues underlying the histo-structural change of developing tongue in Korean native goats by light microscopy (LM). Tongues of the fetuses on days 60, 90, 120 and neonate were examined for the morphological development. In the 60-day-old fetuses, the tongue tissues were differentiated into epithelium, lamina propria and muscle layer. Primordia of filiform, conical, lentiform, fungiform and vallate papillae appeared and rudiments of taste bud were observed in the epithelia of the primordia of the gustatory papillae. The dorsal surface of the lingual epithelia showed a weak PAS positive reaction. Collagenous fibers and small blood vessels were shown in the connective tissues. In the 90-day-old fetuses, Von Ebner’s glands were moderately PAS positive while the muscle fibers and connective tissue were strongly positive for PAS. The collagenous fibers increased and came to have a more complex arrangement in the tongue. The muscle fibers were spread out at various directions and developed in striated muscle bundles. In the 120-day-old fetuses, taste buds were observed in the epithelia of the gustatory papillae, and several well-developed tissues visible such as blood vessels, collagenous fibers, muscle fiber bundles and Von Ebner’s glands. In the neonates, many taste buds were found in a transverse section of the vallate papilla. The muscle layers, Von Ebner’s glands, collagenous fibers and blood vessels were more developed than those of the 120-day old fetuses. These findings indicate that goat tongues have a variety of different shapes during prenatal development.