γ-PGA hydrogel loaded with cell-free fat extract promotes the healing of diabetic wounds

Diabetic wounds are one complication of persistent hyperglycemia and lead to neuropathy and vascular lesions in patients. The promotion of angiogenesis plays an important role in wound healing. Cell-free fat extract (Ceffe) is a cell-free fraction isolated from adipose that is enriched with a range of growth factors, the combination of which can synergistically induce angiogenesis. In this study, we prepared a wound dressing by loading Ceffe with the γ-PGA hydrogel (Ceffe-γ-PGA) to promote the healing of wounds in diabetic mice. The viscosity of Ceffe-γ-PGA was 9.2 pa s, and the water retention rate after 6 hours reached 50%. The slow-release effect of the Ceffe-γ-PGA hydrogel was investigated in vitro in PBS, and the cumulative release rate was 97% after 6 days. Water retention and viscosity analyses revealed that Ceffe-γ-PGA provided a moist environment for the wound surface. The therapeutic effect of the Ceffe-γ-PGA hydrogel on wound healing was studied in vivo in type-II diabetic male db/db mice. After 17 days of wound treatment, the wound area ratio of the Ceffe-γ-PGA group was reduced to 2% of the original, and the capillary density of the Ceffe-γ-PGA group reached 33 mm-2 and was 19 mm-2 higher than that of the untreated group. The cell proliferation rate in the Ceffe-γ-PGA group was 37% higher than that in the untreated group. These results support the use of this system as a promising therapeutic strategy for wound healing in patients with diabetes.