Project description:Tendon is a hypocellular tissue that contains functional cable-like units of type I collagen responsible for the transmission of force from muscle to bone. In the setting of injury or disease, patients can develop chronic tendinopathies that are characterized by pain, loss of function and persistent inflammatory changes that are often difficult to treat. Platelet-rich plasma (PRP) has shown promise in the treatment of chronic tendinopathy, but little is known about the mechanisms by which PRP can improve tendon healing. PRP contains many different growth factors and cytokines, and since these proteins can both activate and inhibit various signaling pathways it has been challenging to determine precisely which signaling pathways and cellular responses are most important. Using state-of-the-art bioinformatics tools and genome wide-expression profiling, the purpose of this study was to determine the signaling pathways activated within cultured tendon fibroblasts in response to PRP treatment. Tendon fibroblasts were isolated from rat tail tendons and embedded in 3D type I collagen gels. Cells were treated with PRP or PPP for 24 hours, and total RNA was extracted for hybridization on Affymetrix arrays.