By placing concentrated platelets and white blood cells into areas (joints) which have a limited blood supply, the injured area gets “induced” to heal. The platelets and white blood cells begin creating a network of fibers and proteins to begin rebuilding and bring growth factors for all cells involved in rebuilding and regenerating.
"Platelets contain many proteins and growth factors..."
Platelets contain many proteins and growth factors which are secreted when they become activated and signal the migration of cells to produce enzymes necessary to digest the old injured tissue and proteins and growth factors to create new tissue. One important cell which is recruited is the mesenchymal stem cell. As we have heard in the news – stem cells rejuvenate any tissue they come in contact with.
As described above the platelets are powerful messenger cells for healing, but credit is also due to the white blood cells as they also contain important cytokines and enzymes. Cytokines (interleukins and lymphokines) are considered regulatory proteins which help to generate an immune response. It is the white blood cells which are considered responsible for long term tissue regeneration via macrophages and increased monocyte adherence.