Silk protein/polyvinylpyrrolidone nanofiber membranes loaded with puerarin accelerate wound healing in mice by reducing the inflammatory response

In modern clinical applications, wound healing remains a considerable challenge. Excessive inflammatory response is associated with delayed wound healing. In this study, we prepared composite nanofibrous membranes by mixing the Chinese herbal extract puerarin (PUE) with natural silk protein (SF) and synthetic polymer polyvinylpyrrolidone (PVP) using electrostatic spinning technique, and conducted a series of studies on the structural and biological properties of the fibrous membranes. The results showed that the loading of PUE increased the diameter, porosity and hydrophilicity of nanofibers, which were more favorable for cell adhesion and proliferation. ABTS radical scavenging assay also showed that the loading of PUE enhanced the antioxidant properties of the fibrous membranes. In addition, SF/PVP/PUE nanofibers are non-toxic and can be used as wound dressings. In vitro experiments showed that SF/PVP/PUE nanofibers could effectively alleviate lipopolysaccharide (LPS)-induced inflammation in Immortalized human keratinocytes (HaCaT) cells and down-regulate pro-inflammatory cytokine expression in cells. In vivo studies further showed that the SF/PVP/PUE nanofibers could effectively accelerate wound repair. The mechanism is that SF/PVP/PUE nanofibers can inhibit the activation and transduction of toll-like receptor 4/myeloid differentiation factor88/nuclear factor kappa B (TLR4/MyD88/NF-κB) and phosphatidylinositol 3-kinase/protein kinase B (PI3K/AKT) signaling pathways, thereby reducing the inflammatory response and achieving wound healing.