Wound healing is a complex series of interactions between various types of cells which is divided into phases of wound healing, these cells includes cytokine mediators and extracellular matrix and the phases of wound healing is very distinct with each other. Success of wound healing is totally dependent on the patients nutritional status and overall health which includes disease states such as diabetes, cancer, and arthritis.
Wound healing is basically a mechanism whereby our body attempts to restore the integrity of the injured body part, it normally takes place in three distinct phases.
- The inflammatory Phase
- Porliferating Phase
- The Remodeling Phase
The inflammatory Phase
The duration of this phase is immediately after wounding which lasts for 2 to 3 days in which bleeding is followed by vasoconstriction and thrombus formation to limit blood loss.
Platelets stick to the damaged endothelial lining of the blood vessels releasing Adenosine Diphosphate (ADP) which causes thrombocytic aggregates to fill the wound. Platelets derived growth factor and transforming growth factor beta which attract inflammatory cell i.e PMN and macrophages. Macrophages removes the devitalized tissue and microorganisms and regulate fibroblastic activity in the proliferative phase.
The Porliferating Phase lasts from 3rd day to 3rd week. It consists of mainly fibroblastic activity with production of collagen and ground substance like glycosaminoglcan and proteoglycan. The wound tissue formed in the early part of this phase which is called granulation tissue. Fibroblasts require vitamin C to produce collagen.
In the later part of Porliferating Phase there is increase in the tensile strength of the wound due to increased collagen deposition and more than 80% of this final strength is achieved with in 30 days.
The Remodeling Phase
The Remodeling Phase starts from 3rd week which may last upto a year, it is characterized by the maturation of collagen. There is a realignment of collagen fibers along the lines of tension, decreased wound vascularity and wound contraction due to fibroblastic and myofibroblastic activity.
Stages of Wound Healing
Wound healing is also sometimes differentiated by different stages. Following are the stages of wound healing,
- Stage of Inflammation.
- Stage of Granulation tissue formation and organization which is due to fibroelastic activity synthesization of collagen and ground substance occurs.
- Stage of epithelialization.
- Stage of scar formation and resorption.
- Stage of maturation.