Diabetic mouse wound healing model

The mice were randomly divided into four groups (n = 5): (1) control group, treated with 100 μL PBS; (2) HA group, treated with 100 μL 1.5% HA (Sodium hyaluronate, Sigma-Aldrich, Missouri, USA, Cat: 63357, isolated from Streptococcus equi with a molecular weight of 1,500,000–1,750,000); (3) hADSC-CM + HA group, treated with 100 μg/mL condensed hADSC-CM in 1.5% HA (100 μL in total); and (4) hFDSPC-CM + HA group, treated with 100 μg/mL hFDSPC-CM in 1.5% HA (100 μL in total). All the mice were anaesthetised with isoflurane inhalation. After being shaved and depilated, a 6-mm-diameter circle, single, dorsal, full-thickness wound (including panniculus carnosus) was produced. The treatment was administered to all mice 1 day after the wound model was established as follows: sodium hyaluronate powder was dissolved in deionised water to form a 1.5% hydrogel (w/v). Condensed hFDSPC-CM/hADSC-CM (10 μg) was mixed with 100 μL 1.5% hydrogel and shaken by vortexing to form hADSC-CM + HA/ hFDSPC-CM + HA mixture for application. A total of 100 μL HA hydrogel or the above mixture was applied to the wound area. The hydrogel was very sticky, so no extra measure was taken to fix it, and this sticky feature enabled the CM to remain on the wound area.