There are three distinct phases of healing that the body goes through following injury. The physiology of Prolotherapy relies on the principle of inflammation. This is a simplified model of how healing occurs:
During the first phase of healing, which is termed the acute inflammation stage, a blood clot forms that traps plasma and surrounding debris and attract an influx of white blood cells. Leukocytes enter the wound and are responsible for killing bacteria, while neutrophils and macrophages begin the repair process and remove dead tissue. Several chemicals are released during this process including prostaglandins which cause pain. Macrophages become involved and healthy cells containing the genetic blueprint of the injured structure multiplies. This entire process is believed to occur within the first 100 hours following an injury.
As the macrophages begin to remove cellular debris and damaged areas, the granulation phase takes place. Some macrophages turn into fibroblasts which make collagen. New blood vessels are formed to provide oxygen and nutrients to the area. The injury site often has a feeling of fullness during this process. This stage continues for 10 days to several weeks.
The third and final phase is remodeling. This phase can last for 1 to 3 months. While the injured area still has a fullness about it, the area usually is no longer tender. Disorganized collagen is seen within the injured ligaments and tendons. Fibroblasts evolve into myofibroblasts that begin to produce contractile muscle fibers that become shorter and tighter. Laxity is removed. By the end of the remodeling phase, the injured ligament or tendon has been completely repaired to its original size, length and eventually level of strength.
The foundations of Prolotherapy rely on using a chemical irritant to initiate this aforementioned process.