Development of an in vitro model of injury-induced osteoarthritis in cartilage explants from adult horses through application of single-impact compressive overload.

The research examines an in-vitro model developed for studying the impacts of injury-induced osteoarthritis on horse cartilage. The study establishes that a strain of 60% at a rate of 100% strain/second is needed for mimicking the damage in full-thickness horse cartilage, providing a way to investigate the disease’s changes and potential treatments.

Methodology

• The scientists obtained full-thickness cartilage explants from the trochlear ridges of the distal femur of six adult horses that have died due to reasons not related to the musculoskeletal system.
• To simulate injuries that could cause osteoarthritis, these explant samples were compressed uniaxially to 50%, 60%, 70%, or 80% strain at a 100% strain/second rate. There were also control specimens that remained uninjured.
• Post this, all specimens were cultured for 28 days before undergoing histological evaluation for early signs and features of osteoarthritis, such as surface damage to articular, chondrocyte cell death, chondrocyte cluster formation, localized cell loss, and the diminishing of the molecules aggrecan and types I and II collagen.

Results

• Compression to all levels of strain triggered some pathological changes reminiscent of clinical osteoarthritis in horses.
• However, only compression to a 60% strain led to significant alterations at both molecular and morphological levels in the extracellular matrix, a three-dimensional network of extracellular macromolecules such as collagen, enzymes, and glycoproteins that provide structural and biochemical support to cells.

Conclusion

• The researchers concluded that to simulate injury in full-thickness cartilage specimens from adult horses, a stress of 60% at a 100% strain/second rate was imperative.
• This in-vitro model could potentially become a robust tool for studying pathophysiologic changes and therapeutic interventions for osteoarthritis, thereby potentially aiding in improving treatments for humans suffering from osteoarthritis.