Interleukin-1 Receptor Antagonist Protein Procession System or IRAP is designed to block the excessive production of interleukin-1 in joints affected by osteoarthritis. Osteoarthritis, or secondary degenerative joint disease (DJD) is a primary cause of lameness in the horse. Cartilage destruction, which leads to secondary DJD, occurs due to inflammatory mediators in the joint, such as interleukin-1. IRAP blocks IL-1 from binding to the tissues and causing damage.

To perform IRAP treatment, a sample of blood taken from the affected horse is incubated with substances that encourage healing, such as growth factors and anti-inflammatory aids. The sample is then “spun” to separate these beneficial substances in the serum from red blood cells. This serum is then injected into the injured joint, halting the inflammatory cycle and encouraging healing. Multiple samples are usually harvested and injected at one to two week intervals. Although research in IRAP therapy are still ongoing, the results are promising.