Cartilage-derived biomarkers and lipid mediators of inflammation in horses with osteochondritis dissecans of the distal intermediate ridge of the tibia.

This research focuses on investigating potential changes in cartilage metabolism in young horses with a condition called osteochondritis dissecans (OCD) to understand whether similar alterations can be observed in older horses displaying OCD symptoms. The study also examines the role of eicosanoids, a group of compounds involved in inflammation, in the development of these symptoms.

Study Design and Methods

• The research team collected synovial fluid from 38 tarsocrural joints of 24 warmblood horses, some of which had symptoms of OCD (22 joints of 16 horses) and some which did not (16 joints of 8 horses).
• To investigate the turnover of type II collagen, they used specific immunoassays for products related to its creation (carboxypropeptide of type II collagen [CPII]) and breakdown (collagenase-cleaved fragments of type II collagen [C2C]).
• The team also evaluated concentrations of glycosaminoglycan (GAG), leukotriene B(4) (LTB(4)), cysteinyl leukotrienes, and prostaglandin E(2) (PGE(2)), comparing the levels found in joints with and without OCD.

Results

• The team found no significant differences in the concentrations of CPII, C2C, and GAG between joints affected by OCD and those that were not. This indicates that the physical conditions in the affected joints were not significantly different from the non-affected ones in terms of collagen or proteoglycan turnover.
• However, they found that fluids from joints presenting OCD symptoms had significantly higher concentrations of LTB(4) and PGE(2) compared to those from non-affected joints. This suggests an increased level of inflammatory activity in the affected joints.

Conclusions

• This study concluded that there were no detectable changes in collagen or proteoglycan turnover in horses aged 24 to 48 months at the time they developed OCD symptoms.
• However, increased levels of LTB(4) and PGE(2) in the synovial fluid of joints with OCD points to these inflammation mediators playing a role in the initiation of OCD symptoms.

This research provides valuable insights into the biochemical changes associated with OCD in horses and highlights areas for further research, especially in understanding the role of eicosanoids in the development of OCD.