ABSTRACT
ObjectiveTo investigate the promotional effect of astragaloside on the repair and healing of chronic non-healing wounds and its mechanism. MethodA total of 60 male SD rats were constructed with full-layer skin defect wounds on the back， and except for the control （Con） group， the rest were constructed with non-healing wounds， which were then randomly divided into the sham-operation （sham） group， the low-dose astragaloside group， the high-dose astragaloside group， the astragaloside + LY294002 ［phosphatidylinositol 3-kinase （PI3K） inhibitor］ group， and the astragaloside + EX527 ［silencing regulatory protein 1 （SIRT1） inhibitor］ group. The percentage of wound area in each group was observed on the 2nd， 4th， 6th， and 8th days after wound molding. Collagen type Ⅰ alpha 1 （COL1A1） and alpha smooth muscle actin （α-SMA） expressions in the wound tissue were detected by immunofluorescence. Hematoxylin and eosin （HE） staining was performed to determine the pathological structure of the wound. The mRNA expression of inflammatory factors in the wound was measured by real-time polymerase chain reaction （Real-time PCR）， and the expression of proteins related to the SIRT1/ nuclear factor （NF）-κB and PI3K/protein kinase B （Akt） signaling pathways in the wound was tested by Western blot. ResultCompared with the sham group， the percentage of postoperative wound area of rats in both low-dose and high-dose astragaloside groups gradually decreased with time， and the efficacy of the high-dose astragaloside group was better. Compared with the Con group， the fluorescence intensity of COL1A1 in wound tissue of the sham group decreased， while the expression of α-SMA increased. The epithelial tissue was severely damaged， with an increase in the thickness， and a large number of inflammatory cells were seen in the infiltration. The mRNA expression of tumor necrosis factor （TNF）-α， interleukin （IL）-1β， IL-6， and inducible nitric oxide synthase （iNOS） was elevated. The protein expression of NF-κB p65， p-PI3K/PI3K， and p-Akt/Akt was elevated， while SIRT1 expression was decreased （P<0.05）. Compared with the sham group， the fluorescence intensity of COL1A1 and α-SMA increased after astragaloside treatment. The number of epithelial cells increased， and the thickness decreased. The inflammatory cells decreased， and the amount of collagen increased. The mRNA expression of TNF-α， IL-1β， IL-6， and iNOS was decreased， and the protein expression of NF-κB p65， p-PI3K/PI3K， and p-Akt/Akt was decreased. SIRT1 was elevated， and the effect was better in the high-dose astragaloside group （P<0.05）. Compared with the high-dose astragaloside group， inhibition of the PI3K/Akt and SIRT1 pathways by LY294002 and EX527 prevented the therapeutic efficacy of astragaloside on chronic non-healing wounds. ConclusionThe topical application of astragaloside significantly promotes the healing of chronic non-healing wounds in rats， and the mechanism may be related to the activation of the PI3K/Akt pathway and the SIRT1/NF-κB pathway.