Comparative histomorphometrical study of the lamellae in odd-toed and even-toed ungulate animals

Abstract

This study aimed to create a hoof lamellae model by combining the histomorphometric data of lamellae from animals with odd and even toes. The comparison study showed that odd-toed horses and donkeys have two unique types of epidermal lamellae (EL) in the innermost layer of the capsular wall, known as primary (PEL) and secondary epidermal lamellae (SEL). In contrast, even-toed cows and camels have only PEL. These lamellae form a complex and complicated dermo-epidermal connection by interlocking with the corresponding primary (PDL) and secondary dermal lamellae (SDL). The PEL were all the same shape, and cells made up the intertubular horn of the stratum medium. Animals with odd toes had SEL. A group of non-cornified basal cells and a central area with partially keratinized cells were composed of these Els. A distinct and straightforward connection between SEL and PEL was shown via connective tissue fibers. In both odd-toed and even-toed animals, the PEL originates from basal cells placed at the proximal extremity of the stratum internum. As the cells migrate towards the outermost edge, they undergo keratinization, contributing to the overall count of keratinized cells in the PEL. The results indicated significant differences in lamellae between those animals with odd-toed and even-toed feet. In addition, the current outcomes deliver a new perspective on the relationship between the architecture of hoof lamellae in animals with odd or even toes and their increased ability for keratin formation, which might explain the development of hoof diseases in the future.

Keywords

• epidermal lamellae
• hoof wall
• stratum interneum