Platelet rich plasma is also obtained from the horse’s blood. As the name implies, PRP is a solution of concentrated platelets suspended in the plasma portion of whole blood. Platelets naturally contain high levels of growth factors, which are important chemical messengers responsible for tissue regeneration in the body. These growth factors are normally released by the platelets when they become activated at the site of an injury. Growth factors are largely responsible for signaling other cells near the site of injury to begin the healing process and also attract and recruit stem cells to the area where they are released. Some of the more important growth factors found in PRP include TGF-β (transforming growth factor beta), PDGF (platelet derived growth factor), EGF (epidermal growth factor), VEGF (vascular endothelial growth factor), and FGF (fibroblast growth factor). Each of these growth factors plays a specific role in the tissue healing process, but collectively they work to attract the migration of stem cells to the site of injury, stimulate the growth of connective tissue, and create new blood vessels to bring nutrients and oxygen into the site of injury.
Right hind lateral suspensory branch injury prior to treatment with PRP. Note the dark fissures in the ligament indicating fiber tearing and edema.
Same RH lateral suspensory branch, several weeks after treatment with PRP. Significant healing has occurred within the ligament following treatment.
PRP IN TENDON AND LIGAMENT INJURIES
PRP is very useful in the healing of tendons and ligaments because it delivers a high dose of these important growth factors right to the site of injury. Tendons and ligaments are notoriously difficult to heal because they are made primarily from connective tissue and have a sparse blood supply. In the horse, the flexor tendons and suspensory ligaments also have very little vessel-rich muscle or soft tissue surrounding them, making the equine tendon or ligament injury even more challenging to treat than similar injuries in other species. When healing of a tendon or ligament occurs in a low oxygen environment, it is more likely to result in increased scar tissue and fibrosis. This scar tissue is disorganized and does not have the same tensile strength as the original tendon making it quite susceptible to reinjury. When we treat a tendon or ligament lesion with PRP, we encourage the horse’s body to slow down scar tissue formation by attracting stem cells to the area and stimulating new blood vessels to form around the injury. This allows more oxygen carrying cells to reach the site of injury and signals the tendon to heal more physiologically normal, reducing scarring and fibrosis.
Atlantic Equine Services can treat your horse with PRP right at your farm. After a tendon or ligament injury has been identified with a lameness workup and ultrasound examination, treatment of the injury with PRP can be initiated. Whole blood is collected from your horse and is processed in a special centrifuge to remove most of the red blood cells and to optimize the amount of platelets and white blood cells left in the remaining plasma. Next, your horse is sedated and the site for injection is clipped and sterilized for injection. Local anesthesia is injected under the skin around the site of the injury. The PRP is then injected into your horse under ultrasound guidance directly into the damaged region of the tendon or ligament. This ensures that the healing growth factors are placed directly in the area where they are most needed. PRP is also injected into joints in some instances, and is frequently used in conjunction with stem cell therapy or shockwave therapy.