Stromal vascular fraction gel promoted wound healing and peripheral nerve repair in diabetic rats via TLRs/MyD88/NF-κB signaling pathway

Diabetes mellitus (DM) contributes to impaired wound healing. This study was aimed to evaluate the effect of stromal vascular fraction (SVF) gel extracted from rats on diabetic ulcers wound healing and peripheral nerve repair. 60 Sprague Dawley (SD) rats were divided into 6 groups, including control, model, SVF-gel low dose (SVF-gel-L), SVF-gel high dose (SVF-gel-H), ST2825, and SVF-gel-H + CL075 groups. Wound closure rate was recorded. The histopathological changes and deposition change of collagen fibre were identified. The content of TNF-α, IL-1β, VEGF, and bFGF were detected. Immunohistochemical, immunofluorescence and western blot were employed to determine the protein expression. We identified SVF-gel could promoted wound healing, restored normal cutaneous structures of the wound, promoted collagen deposition, while diminished fibrosis and inflammation. In addition, SVF-gel promoted angiogenesis and peripheral nerve recovery, diminished the expression of TLRs/MyD88/NF-κB signaling pathway. However, the protective effect of SVF-gel could be revised by CL075 co-treatment. Furthermore, ST2825 also promoted wound healing, but its effect was lower than that with SVF-gel-H treatment. SVF gel promotes the healing of diabetic skin ulcer tissue and regeneration of damaged peripheral nerve, diminished inflammatory factor infiltration. The mechanism maybe related to suppress the activation of TLRs/MyD88/NF-κB signaling pathway.