Wnt/β-catenin signaling of cartilage canal and osteochondral junction chondrocytes and full thickness cartilage in early equine osteochondrosis.

The research investigates the difference in gene and protein expression levels related to Wnt signaling molecules in cartilage cells (chondrocytes) of foals with and without early osteochondrosis, a disease affecting the joints of horses. The researchers expected to find an increased expression of elements involved in the Wnt signaling pathway in osteochondral junction and cartilage canal chondrocytes of affected foals.

Methodology

• 17 immature horses were examined, with their osteochondral samples (samples of bone and cartilage tissues) and cDNA from whole cartilage and chondrocytes taken from cartilage canals and osteochondral junctions.
• The osteochondral samples were prepared using paraffin embedding. The researchers used a process called laser capture microdissection to capture highly specific populations of chondrocytes.
• Comparison was made between cartilage/ostochondral samples and cDNA from foals with early Osteochondrosis (7 foals) and normal controls (8 for cartilage samples and 10 for cDNA).
• Two-step real-time qPCR was employed to evaluate the expression levels of equine-specific Wnt signaling molecule mRNA.
• They also used immunohistochemistry, a lab technique used to visually localize proteins within tissues, to determine the spatial tissue protein expression of β-catenin, Wnt-11, Wnt-4, and Dkk-1.

Findings

• A significant decrease in Wnt-11 expression and an increase in β-catenin, Wnt-5b, Dkk-1, Lrp6, Wif-1, Axin1, and SC-PEP gene expression was observed in cartilage canal chondrocytes from foals with early Osteochondrosis as compared to normal controls.
• There was also a significant increase in β-catenin gene expression in osteochondral junction chondrocytes of OC affected foals as compared to controls.

Conclusion

The researchers concluded that there is a considerable difference in gene expression for OC chondrocytes, suggesting that pathways related to catabolism (the breakdown of complex molecules) and the inhibition of chondrocyte maturation may play a significant role in early OC pathogenesis (the origination and development of the disease). Through this study, they have provided critical insights into the molecular changes that occur in early equine osteochondrosis, effectively contributing to the understanding and potential future treatment of this disease.