Effect of exercise on thicknesses of mature hyaline cartilage, calcified cartilage, and subchondral bone of equine tarsi.

The research investigated the effects of various levels of exercise on the thickness patterns of different cartilages and subchondral bone in horse’s ankles. They found that more intense exercise led to thicker cartilages and bone, with the greatest thickness observed in areas that usually experience high stress and damage.

Objectives and Sample Population

• The researchers aimed to understand the effects of different levels of physical activity on the thickness of the hyaline cartilage (HC), calcified cartilage (CC), and subchondral bone (SCB) in the tarsi (ankles) of horses.
• The sample for this study comprised 30 tarsi from deceased horses with recorded histories of exercise exposure. The exercise histories were classified into three categories: pasture exercise (PE), low-intensity riding (LE), and high-intensity competition riding (EE).

Procedures and Methodology

• The tarsi from the corpse horses were assigned to the three distinct groups based on their documented exercise histories.
• The tissue from the lower tarsal joints underwent histological preparation. The thickness of HC, CC, and SCB were measured at regular sites at different locations (medial, midline and lateral) across the joints using a histomorphometric technique.

Results and Findings

• HC, CC, and SCB thickness was notably greater in the tarsi from horses who had participated in high-intensity exercise (EE group), compared to those from the low-intensity (LE) or only pasture exercise (PE) groups.
• The study also found specific places across the joints where the HC, CC, and SCB were significantly thicker in the EE tarsi compared to the LE.
• Similarly, the SCB was thickest in EE tarsi and thinnest in LE tarsi, especially at sites that have been reported to experience the highest strains and damage.

Conclusions and Clinical Relevance

• The research concluded that increased exercise is associated with greater thickness of HC, CC, and SCB in mature horses.
• The thickness at specific sites that experience high compressive strain is notable, leading the researchers to suggest a higher risk of osteoarthritic changes in these areas.
• The findings of this study can provide insights into how much exercise can foster adaptive responses on the one hand, but also potentially contribute to detrimental pathologies on the other hand.