Diabetic skin wound animal model and treatment

Adult female Sprague Dawley rats (4–6 weeks, 150–200 g, grade: clean, license: SCXK 2013-0005) were purchased from SLAC Laboratory Animal Co., Ltd (Shanghai, China) and used to establish a rat model for diabetes as described previously²⁷. All animal experiments were conducted in accordance with the National Institutes of Health Guide for the Care and Use of Laboratory Animals and approved by the Biological Research Ethics Committee of the Chinese Academy of Sciences. Rats were maintained on a 12 h light cycle in the animal facility of the Shanghai Tenth People’s Hospital of China. Streptozotocin was injected intraperitoneally (100 mg/kg in 0.01 M sodium citrate, pH 4.3) to induce diabetes. Blood glucose level was maintained between 16.7 and 33.3 mmol/l by 6–18 units/day of insulin (Wan-Bang Biochemical Medicine Co. Ltd, Xuzhou, China). After 4 weeks, a model of DFUs was created in rats anesthetized with isoflurane inhalation. A single round full-thickness skin wound was created with a 5-mm disposable skin biopsy punch and Westcott scissors on the dorsum of hind feet of the diabetic rats.