Dang-Gui-Si-Ni decoction facilitates wound healing in diabetic foot ulcers by regulating expression of AGEs/RAGE/TGF-β/Smad2/3

Abstract

Diabetic foot ulcer (DFU) is a predominant complication of diabetes mellitus with poor prognosis accompanied by high amputation and mortality rates. Dang-Gui-Si-Ni decoction (DSD), as a classic formula with a long history in China, has been found to improve DFU symptoms. However, mechanism of DSD for DFU therapy remains unclear with no systematic elaboration. In vivo, following establishment of DFU rat model, DSD intervention with low, medium and high doses was done, with Metformin (DM) as a positive control group. With wound healing detection, pathological changes by HE staining, inflammatory factor expression by ELISA and qRT-PCR, oxidative stress levels by ELISA, and AGEs/RAGE/TGF-β/Smad2/3 expression by Western blot were performed. In vitro, intervention with LY2109761 (TGF-β pathway inhibitor) based on DSD treatment in human dermal fibroblast-adult (HDF-a) cells was made. Cell viability by CCK8, migration ability by cell scratch, apoptosis by flow cytometry, and AGEs/RAGE/TGF-β/Smad2/3 expression by Western blot were measured. DFU rats exhibited elevated AGEs/RAGE expression, whereas decreased TGF-β1 and p-Smad3/Smad3 protein expression, accompanied by higher IL-1β, IL-6, TNF-α levels, and oxidative stress. DSD intervention reversed above effects. Glucose induction caused lower cell viability, migration, TGF-β1 and p-Smad3/Smad3 protein expression, with increased apoptosis and AGEs/RAGE expression in HDF-a cells. These effects were reversed after DSD intervention, and further LY2109761 intervention inhibited DSD effects in cells. DSD intervention may facilitate wound healing in DFU by regulating expression of AGEs/RAGE/TGF-β/Smad2/3, providing scientific experimental evidence for DSD clinical application for DFU therapy.

Keywords: Angiogenes; Dang-Gui-Si-Ni decoction; Diabetic foot ulcer; Smad2/3; TGF-β.