Topical Application of miR-200b-3p by Poloxamer 407-Based Hydrogel Accelerates Diabetic Wound Healing

Abstract

Background: Diabetic foot ulcers (DFUs) are refractory to healing owing to excessive oxidative stress, increased proinflammatory cytokines, accumulation of senescent cells, and impaired angiogenesis. Local injections of miR-146a-5p and miR-200b-3p have pro-healing properties in diabetic wounds but are unrealistic in clinical practice. We investigated whether the topical application of miR-146a-5p and miR-200b-3p using a poloxamer 407-based hydrogel accelerated diabetic wound healing in db/db diabetic mice. In addition, we compared these two miRNAs to select a better microRNA for further application in patients with DFUs. Methods: The wound was created using an 8-mm punch biopsy. One hundred microliters of poloxamer P407 hydrogel formulations (gel, gel+miR-negative control, gel+miR-146a-5p, and gel+miR-200b-3p) were topically applied to each wound, and the hydrogel was changed every two days. Skin samples were sent for real-time PCR, H&E staining, and immunohistochemical staining. Results: On the 14th day, the gel+miR-200b-3p group demonstrated the best wound healing performance compared with the other three groups, as supported by the reduced wound size and enhanced granulation tissue thickness. Mechanistic insights showed that gel+miR-200b-3p caused significant upregulation of Col1α2 gene expression and downregulation of Nox1, Nox4, HO-1, IL-6, IL-1β, OGT, p21, and p53 gene expression. The CD68 protein levels were significantly decreased in the gel+miR-146a-5p and gel+miR-200b-3p groups. Furthermore, CD31 proteins showed a significant increase in the gel+miR-200b-3p group compared with the other three groups. These data demonstrate that the gel+miR-200b-3p group had better pro-healing efficacy than the gel+miR-146a-5p group through its effects on anti-oxidative stress, anti-inflammation, anti-senescence, and pro-angiogenesis. Conclusion: Topical application of miR-200b-3p by poloxamer 407 hydrogel showed better results in accelerating diabetic wound healing than miR-146a-5p. These data suggest that topical miR-200b-3p formulation is an effective treatment approach for DFUs.