4'-hydroxychalcone nanofiber hydrogel dressing promotes diabetic chronic wound healing by regulating macrophage polarization via the TLR/IL-17/TNF signaling pathway.

Background: The activation and polarization of macrophages play a crucial role in the inflammatory response in chronic diabetic wound healing. Modulating macrophage polarization toward the M2 phenotype can facilitate wound healing. 4'-Hydroxychalcone (4HC) possesses antioxidant and anti-inflammatory properties, and the preparation of novel drugs through electrospun nanofibers and hydrogels can enhance its therapeutic effects. However, the effects of the 4'-hydroxychalcone nanofiber hydrogel dressing (P-4HC) prepared in this study on macrophage polarization and its potential mechanisms in the treatment of diabetic chronic wounds have not yet been elucidated. Objective: This study aimed to investigate the effect of P-4HC on macrophage polarization in diabetic chronic wounds and to elucidate its potential mechanisms of action. Methods: In vitro, cell compatibility tests were conducted using L929, HUVECs, and RAW264.7, along with ROS, scratch assays, tube formation assays, immunofluorescence tests for macrophage phenotypes, flow cytometry, and Western blotting (WB). In vivo, a diabetic mouse skin wound model was established, and HE and Masson staining, immunohistochemical staining of COL3A1, HIF-1a, and VEGF, immunofluorescence staining of CD31, CD86, and CD206, WB, RT-qPCR, and ELISA were conducted. Results: In vitro and in vivo, P-4HC exhibited good cell compatibility, improved tissue hypoxia, and promoted angiogenesis and collagen deposition. It promoted the transition of macrophages from M1 to M2 type, downregulated pro-inflammatory cytokine levels, and upregulated anti-inflammatory cytokines and pro-angiogenic cytokines, thereby promoting the healing of diabetic chronic wounds. Transcriptome analysis indicated that the TLR/IL-17/TNF pathway was the main pathway mediating the effects of P-4HC. P-4HC promoted macrophage polarization toward the M2 phenotype and enhanced wound healing by inhibiting the expression of TLR9, IL-17A, and TRAF1, thereby suppressing the TLR/IL-17/TNF signaling pathway. Conclusion: P-4HC promotes the polarization of macrophages from M1 to M2 phenotype by inhibiting the TLR/IL-17/TNF signaling pathway, thereby suppressing inflammation and mitigating tissue damage. These findings provide a scientific basis for the treatment of chronic diabetic wounds and lay a foundation for exploring new therapeutic strategies for diabetes-induced inflammation based on macrophage polarization.