Histologic evaluation of the diversity of epidermal laminae in hooves of horses without clinical signs of laminitis.

The researchers examined different types of tissue structure in horse hooves to develop a more effective system for diagnosing and studying laminitis, a disease that affects horse hooves. Although they found various tissue patterns, these changes were not exclusive indicators of the disease, calling for more precise evaluation techniques.

Research Methodology

• Various sections of horse hoof tissue were collected from 35 deceased Thoroughbred horses, including foals, yearlings, two-year-olds, racing horses, and mares.
• The samples were processed using a chemical, formalin, to preserve their structure.
• The processed samples were embedded in paraffin and stained with Hematoxylin and Eosin (H&E) to examine the structure of the primary and secondary epidermal laminae, the complex tissue structures within a horse’s hoof that help with weight distribution and shock absorption.
• Additionally, a specialised procedure called immunohistochemical staining was utilised to investigate the expression levels of cytokeratins (CK), structural proteins in the epithelial cells of the hoof.

Key Findings

• The researchers found that primary epidermal laminae (PEL), secondary epidermal laminae (SEL), and tips of PEL in the horse hooves could be categorized into different morphological patterns.
• They also discovered that the SEL type varied based on their position within the laminar interface, indicating differential tissue structure throughout the hoof.
• Under normal conditions, basal cells of the SEL attached to the PEL sides were immunoreactive to CK14 and CK8.12, meaning these cells displayed a reaction when introduced to these specific markers.
• In some SEL on the tips of PEL, the suprabasal cells expressed CK14 and CK8.12, indicating a hyperplastic pattern or an increased rate of cell production.

Research Conclusions

• The study revealed that the tissue diversity within horse hooves is a result of the combined morphologies of primary and secondary epidermal laminae.
• Notably, while hyperplastic changes were detected in the laminar interface, these were not necessarily indicative of laminitis.
• Such changes, the authors suggest, might occur independent of clinical disease, underlining the need for more nuanced and precise evaluation techniques for diagnosing hoof diseases like laminitis.
• The researchers proposed their classification system as a tool for more accurate histological evaluation of the laminae in horse hooves. They hope that their work might lead to more effective diagnoses and improved treatments for hoof health in horses.