Insulin Regulates Epidermal Stem Cells Dedifferenation And Promotes Diabetic Wound Healing

Objective: To explore whether insulin promotes wound healing in diabetes mellitus(DM)by regulating the dedifferentiation of epidermal stem cells(ESCs).Methods: Twenty-one female Sprague Dawley rats(SD)(weighing 250–300 g)were fed with high-sugar and high-fat diet for 6 weeks,followed by a single intraperitoneal injection of streptozocin(STZ,30 mg/kg)to establish a type 2 diabetic rat models and the random blood glucose were measured ≥16.8 mmol/L.The diabetic rats were randomly classified as follows: nine in the insulin group(experimental group),nine in the saline group(control group),and three in the blank group.A 2 × 2-cm full thickness was made on the back of each rat Wet dressing with an insulin solution in 0.9% saline was performed over 200 m U/L per square centimeter wound in the experimental group;the solution wet-dress was changed every day.The rats in the control group were wet-dressed with standard saline similar to the experimental group.The blank group was not specially treated(only the whole skin specimens from the back were collected).On days 3,5,and 7,wet dressing was performed along the wound edge with insulin solution in 0.9% saline.The whole skin from the back of the experimental and control animals was collected approximately 0.5 cm from the trauma edge,and 0-day skin tissue was collected from the blank group animals.The skin tissue was immunohistochemically stained to identify cell keratin10(CK10),CK19,β1-integrin,and proliferating cell nuclear antigen(PCNA).The expression levels of these proteins were detected using western blot,and differences in the expression levels of these proteins between the two groups of skin tissues were analyzed.Results:1.The modeling success rate of diabetic rats was 100%.The random blood glucose levels of ≥16.8 mmol/L was confirmed their DM status.2.Immunohistochemical results showed that CK10 was positive in the blank group and the positive degree was higher than that in the experimental group and control group.CK19,β1-integrin and PCNA were negative in the blank group,but positive in the experimental group and control group,and the positive degree of CK19,β1-integrin and PCNA in the experimental group was higher than that in the control group.3.Western Blot results showed that CK10 expression in blank group was higher than that in experimental group and control group,and CK10 expression in experimental group was lower than that in control group,the difference was statistically significant(P < 0.05);CK19,β1-integrin and PCNA expression in blank group was lower than that in experimental group and control group.The expression of CK19,β1-integrin and PCNA in the experimental group was higher than that in the control group,and the difference was statistically significant(P <0.05).Conclusion: One of the mechanisms through which insulin promotes the regeneration of damaged skin may be related to its ability to induce the dedifferentiation of ESCs.