Biomechanical and molecular characteristics of hereditary equine regional dermal asthenia in Quarter Horses.

This research explores the biomechanical and molecular characteristics of Hereditary equine regional dermal asthenia (HERDA), a hereditary skin disorder mostly found in Quarter Horses. The study demonstrates that affected horses have significantly weaker skin and more soluble collagen, contributing to the poor wound healing and fragility associated with the disorder.

Biomechanical Assessment of HERDA

The researchers used an Instron Universal Testing Instrument to measure the biomechanical properties of horse skin. These included tensile strength (the ability to withstand tension before breaking), modulus of elasticity (the degree of stiffness or deformation in response to stress), energy to failure (the total amount of energy absorbed by a material before it fails), and skin thickness.

• The skin samples were taken from 10 HERDA-affected horses and 6 unaffected horses.
• The findings revealed a significant reduction in tensile strength in affected horses, indicating weaker skin that is more prone to damage and tears.
• Significant differences were also found in terms of modulus of elasticity and energy to failure across different skin sample locations, suggesting a widespread weakness in the skin of affected horses.
• However, although there was a variation in skin thickness among sample locations, only one location showed a significant difference.

Molecular Analysis of HERDA

The research also investigated the molecular components of horse skin, focusing on total soluble collagen and glycosaminoglycan concentrations.

• Collagen acts as an essential component in maintaining skin strength and elasticity. Glycosaminoglycans contribute to skin hydration and resistance.
• For this aspect of the study, skin samples were collected from 13 affected and 12 unaffected horses.
• The results showed that affected horses had significantly higher amounts of total soluble collagen than unaffected horses, which may contribute to the hyper-extensibility and fragility characteristics of HERDA skin.
• No significant difference was identified in glycosaminoglycan concentration between the two groups.

Implications of the Findings

• The findings provide a better characterization of HERDA, shedding light on the biomechanical weaknesses of the skin in affected horses. This could potentially guide the development of treatments or strategies for managing the disorder.
• The results also confirm that the biomechanical deficiencies in HERDA are not restricted to specific regions of the horses’ skin but are spread across different locations. This has implications for the diagnosis and care of affected horses, signaling the need for widespread skin protection measures.