Hydrocolloid dressing improves wound healing by increasing M2 macrophage polarization in mice with diabetes

Impaired wound healing is one of the most common complications of diabetes, and is known to be caused by multiple complicated factors. For instance, impaired angiogenesis, neuropathy, and hyperglycemia all function to delay subsequent wound closure. Alternatively, moist wound healing, which provides an appropriate environment for wounds, was reported to permit rapid healing by managing wound exudate. Accordingly, wound dressing materials that facilitate moist healing have been developed. The present study sought to clarify the effects of wound dressing material for moist healing of diabetic wounds, in terms of the dynamics of angiogenic factors and macrophages, using a mouse model of naturally occurring diabetes. Wounds with full-thickness skin defects were inflicted on the backs of mice and covered with dressing materials of hydrogel or gauze (control), which were retained for 3, 5, 7, 10, or 14 days following wound generation. During this time, the localization of neutrophils, fibroblasts and macrophages as well as the expression of vascular endothelial growth factor (VEGF) in the wounds and surrounding areas was observed each day. Healing clearly occurred in the hydrogel group with an increase in neutrophils and the angiogenic factor, VEGF. Moreover, the use of hydrogel resulted in a rapid rise in M1 macrophages, which appeared in the early stage of the injury, as well as rapid subsequent appearance of M2 macrophages. Thus, herein, we demonstrate that the formation of a moist environment via wound dressing material effectively improves diabetic wound healing.