Histological and Morphometrical Study of the Filiform Papillae in the Domestic Rabbit (Oryctolagus cuniculus)

Abstract

The domestic rabbit is often preferred as an experimental model in diverse research and especially those regarding pathologies of the oral cavity, both in human and veterinary medicine. From five domestic mixed breed rabbits, fragments were harvested from the three regions of the tongue: apex, body and root, for histological investigations. The samples were processed by embedding in paraffin, sectioned at a thickness of 5 µm and stained with Goldner’s trichrome method. The histological examination highlighted the presence of the filiform papillae on the entire dorsal surface of the tongue, with morphological particular carachteristics for each portion. The dimension of the filiform papillae of the rabbit’s tongue differs both regarding the length as well as the thickness and density. The shortest filiform papillae were found on the tip of the tongue, then the length increases progressively, reaching the maximum level on the middle portion and decreases in the last portion. The density also differs, in in the three compartments examined, being the highest in the anterior part and the lowest in the posterior part. The thickness of the filiform papillae is inversely proportional to their density. The thickness of the papillae is smaller where the density is higher and highest where the density is lowest. The upper surface of the filiform papillae is variably keratinized depending on the lingual segment. The papillae with the highest level of keratinization are arranged in the body part of the tongue, and those at the tip and root are slightly lower.