Astragaloside IV enhances diabetic wound healing involving upregulation of alternatively activated macrophages

Astragaloside IV (AS-IV), one of the major active compounds extracted from Astragali Radix, has been used experimentally for its potent antiinflammatory and immunoregulatory activities. In this study, we further investigate the potential efficacy of AS-IV on impaired wound healing in streptozotocin-induced diabetic mice. A full-thickness skin wound was produced on the back of diabetic mice and treated with AS-IV or vehicle topically. Our results showed that AS-IV application promoted diabetic wound repair with wounds gaping narrower and exhibiting augmented reepithelialization. AS-IV enhanced the collagen deposition and the expression of extracellular matrix (ECM)-related genes such as fibronectin and collagen IIIa, which implies a direct effect of AS-IV on matrix synthesis. AS-IV also improved the new blood vessel formation in wound tissue with increased numbers of endothelial cells and enhanced expression of VEGF and vWF. Moreover, the beneficial effect of AS-IV was related to the development of polarized alternatively activated macrophages, which involved in resolution of inflammation and facilitation of wound repair. All together, these findings suggest that AS-IV may play a potential effect on maintenance of cutaneous homeostasis and acceleration of diabetic wound healing.