Effect of interleukin 1 on articular cartilage from young and aged horses and comparison with metabolism of osteoarthritic cartilage.

This research investigates how interleukin 1 (IL-1), a molecule component of the immune system, affects the cartilage of young and aged horses, also comparing it to the metabolism of osteoarthritic cartilage. It was found that IL-1 decreases the synthesis of matrix components in articular cartilage, while simultaneously increasing the production and activity of a particular degradating enzyme. Aged horses exhibited less overall metabolic activity in their cartilage compared to young horses.

Research Methodology

• The researchers investigated the effect of interleukin 1 (IL-1), an cytokine component of the immune system, on equine articular cartilage using a culture system created from cartilage tissue (cartilage explant).
• The process of matrix proteoglycan synthesis was measured using [35S]O4 incorporation into the cartilage.
• They investigated the degradation of proteoglycan by measuring [35S]O4 release from the cartilage into the medium of the culture system.
• The team studied the synthesis of total protein by the cartilage and the synthesis of a specific enzyme called stromelysin (a metalloproteinase-3) through Sodium dodecyl sulfate-polyacrylamide gel electrophoresis method.

Research Findings

• The study revealed that the presence of IL-1 in the culture system decreased the matrix proteoglycan synthesis by cartilage significantly over time (45, 59.7, and 37.5% after 1, 3, and 5 days respectively).
• They found no alteration in the process of proteoglycan degradation.
• The research indicated that cartilage exposed to IL-1 decreased total protein synthesis progressively (45, 68, and 87% after 1, 3, and 5 days respectively) while selectively inducing the synthesis of the metalloproteinase-3 enzyme stromelysin.
• A comparative study revealed that the baseline total protein synthesis and the synthesis of stromelysin by articular cartilage from adult and aged horses was substantially less than that by young horses.
• The research also found that IL-1-induced reduction in total protein synthesis might not be a feature of equine articular cartilage from joints affected by osteoarthritis natural to horses. This was based on the observed overall increase in protein synthesis by osteoarthritic tissues in the culture system.

Conclusion

• The introduction of IL-1 into an equine cartilage culture media resulted in decreased synthesis of matrix components and an increased synthesis and activity of a specific degradation enzyme.
• Aged horses exhibited less overall metabolic activity in their cartilage compared to young horses, implying that age, too, plays a significant role in cartilage metabolism.