Histomorphometric evaluation of the effect of early exercise on subchondral vascularity in the third carpal bone of horses.

The research studies if there are changes in the cartilage and bone beneath it in the third carpal bone of young Thoroughbred horses due to early conditioning exercises. The researchers found that while exercise seemed to increase the area of vascular channels, or spaces for blood vessels, in the bone, the differences were not significant.

Methodology

• The research was conducted on nine 18-month-old Thoroughbreds, in which both the third carpal bones of the horses were evaluated.
• Four of these horses had only spontaneously exercised at pasture, while five had also been given additional conditioning exercises from approximately three weeks of age.
• Histomorphometric variables were observed, which included thickness of hyaline (smooth, non-calcified) and calcified cartilage, orientation of collagen,and the rugosity, or roughness, of osteochondral (bone and cartilage) junction.

Results

• The area of vascular channels, spaces in the bone filled with blood vessels, was found to be larger in the group of horses that exercised than it was in the control group.
• Despite the differences observed in vascular channel size, none of the variables were found to be significantly different between the groups.
• Interestingly, the area of vascular channels was found to be the highest in the dorsal (back) aspect of both groups, a region that is known to be susceptible to osteochondral fragmentation, or breakdown of bone and cartilage.
• The researchers found that all the variables had significant site-specific variations, which means the findings varied depending on where they were measured on the bone.

Conclusion

• In their conclusion, the researchers suggested that the mild exercise conducted in both groups during the developmental period appeared to increase the area of vascular channels beneath the calcified cartilage layer in the third carpal bone.
• This observed increase could be associated with high stress on the dorsal aspect of the radial facet, an area known to be vulnerable to the breakdown of bone and cartilage.