Exercise affects the mechanical properties and histological appearance of equine articular cartilage.

The research article presents a study investigating how high-intensity training impacts the structure and mechanical characteristics of cartilage in horses, contributing to a common injury.

Objective of the Study

• This study aimed to examine how the intensity of exercise may affect the mechanical behaviour and histology of cartilage in horses and to explore the relationship between these two aspects.

Procedure of the Study

• The research involved two-year-old horses subjected to 19 weeks of different training intensities: high-intensity treadmill training and low-intensity exercise. These two groups of horses were then compared to uncover any correlations between histology and mechanical behaviour related to exercise intensity.
• After euthanasia, the researchers identified dorsal and palmar test sites on radial, intermediate, and third carpal articular surfaces.

Methodology

• Through an automated creep indentation apparatus, the team measured the mechanical characteristics of the cartilage. This device has been previously utilized for studying equine cartilage.
• The morphology of the cartilage was assessed using sections stained with haematoxylin and eosin and toluidine blue, which are common dyeing techniques used in histology.

Findings

• Results showed that dorsal cartilage (the top part of the joint) was less permeable, thinner and displayed a loss of arrangement of chondrocytes (cartilage cells) compared to palmar cartilage (the bottom part of the joint).
• The cartilage from horses that underwent high-intensity training showed more fibrillation and chondrocyte clusters – signs of wear and tear – compared to the cartilage from horses subjected to low-intensity exercise.
• Among the sensors used for high-intensity training, researchers found that the dorsal radial carpal cartilage and third carpal cartilage were significantly less stiff than those in the low-intensity exercise group.

Conclusion

• The findings imply that the mechanical properties and morphology of carpal cartilage have topographical differences and are affected by the intensity of exercise.
• The research suggests that strenuous training could lead to cartilage deterioration at locations susceptible to lesions, hence contributing to dorsal carpal osteochondral injury, a prevalent cause of diminished performance in highly trained horses.