Dynamic Behavior of Macrophages in Wound Healing

Abstract

The first line of protection against infection for the human body is the skin. A break in this line of defense is called a wound. After the protective barrier is broken, the process of wound healing starts without delay. Wound healing is complex and dynamic. Most of the time wounds progress through phases depending upon the internal and external forces at work within the patient. Wound healing progresses through four phases. They are hemostasis, inflammation, proliferation and remodeling. This study describes a mathematical model which gives a possible explanation to the role and importance of macrophage phenotypes M1: inflammatory macrophages, M2: repair macrophages and MR: regulatory macrophages during the inflammatory phase of wound healing. Six differential equations were formulated and solved numerically. The model results suggest that M1 macrophages are the first macrophage phenotype to enter into the wound and the decrease in the amount of these macrophages after inflammatory phase is a good sign that the wound is healing normally. Also, the imbalance between pro-inflammatory macrophages and repair macrophages is not damaging to the wound provided there is sufficient interleukin-10 (IL-10) in the wound. The model result also indicates that MR macrophage phenotype is very important during the inflammatory phase of wound repair since they secrete IL-10 which inhibits pro-inflammatory macrophages. As a result, a possible explanation is offered as to how wounds can be stalled at the inflammatory phase of wound healing.