Background: This study aims to investigate the effect of integrin β1 on wound healing induced by adipose-derived stem cells (ADSCs), as well as the corresponding mechanism. Methods: Integrin β1 was overexpressed in ADSCs. Thereafter, flow cytometry and transwell chambers technology were used to measure the endothelial-like differentiation (CD31 as a biomarker of endothelial cell) and cell migration, respectively. Western blot was used to detect the activation of PI3K/AKT, NF-κB and ERK signaling pathways. The effects of integrin β1 overexpression on healing time, healing rate and fibroblast number were further evaluated in the rat models of chronic refractory wound. Results: The overexpression of integrin β1 increased CD31+ endothelial-like cells (about 3.6-fold), promoted cell migration (about 1.9-fold) and enhanced the activation of PI3K (p-PI3K; about 2.1-fold) and AKT (p-AKT; about 2.2-fold). These effects were all weakened when PI3K/AKT pathway was inhibited by LY294002 treatment. In addition, the experiments in rat wound models showed that integrin β1 overexpression obviously shortened healing time (approximately 0.41-fold), increased healing rate (about 2.7-fold, 2.8-fold and 1.6-fold at day 7, 14 and 21) and increased the number of fibroblasts (approximately 3.1-fold at day 21). All of the above differences were statistically significant (p < 0.05). Conclusion Integrin β1 can promote the migration and endothelial-like differentiation of ADSCs by activating PI3K/AKT pathway and then enhance the function of ADSCs in promoting wound healing.

Objective To explore the application of UW solution in the replantation of the rat limb,and to explore a simple method for the ideal preservation of the amputated limbs.Methods From September,2017 to Janurary,2018,one hundred and twenty healthy adult male SD rats,weight 320-350 g,were randomly divided into 8 groups:A,B,C,D,E,F,G,H group.The isolated limbs of the control group A,C,E,G were cryopreserved in refrigerator at 4 ℃,while those of the experiment group B,D,F,H were preserved under the same condition after being perfused with UW solution.All the severed limbs were replanted back to the rats after different time length of cry opreservation:A,B 12 hours,C,D 20 hours,E,F 28 hours and G,H 36 hours.During the operations the femoral artery and venous patency were detected immediately after anastomosis.And after the operations the survival rates of limb replantation were observed.On the third day after the limb replantation,the tibial posterior muscle tissue was examined for pathology.The cell areas in pathological photographs were compared with Image analysis software Image-pro Plus 6.0 and the ultra structural changes of skeletal muscle tissue were observed.Results The femoral artery and venous patency in experiment group A,C,E and control group B,D,F were all 100 percent.However,in the group G,H the severed limb vessels changed obviously,the patency dropped markedly and the survival rates of limb replantation turned out to be 0.The experiment groups perfused with UW solutions,had relatively higher survival rates compared with the control groups (12 h:93.33％ vs.53.33％,20 h:80.00％ vs.40.00％,28 h:53.33％ vs.13.33％) and the skeletal muscles edema was lighter than that of the control group,with a larger proportion of cell areas(12 h:69.49±8.57 vs.44.75±6.34,20 h:56.34±7.73 vs.36.69±5.74,28 h:45.76±8.23 vs.31.49±7.72).There was a significantly difference (P＜0.05).Electron microscope observation showed that the experiment group bore a lighter damage of myofibril,interstitial tissue and mitochondria compared with the control group.Conclusion The combination of UW solution and cryopreservation of organs is an ideal and proper way to preserve the amputation limb,to extend the time limit for replantation,and to achieve a better recovery effect of postoperative limb function.Besides,UW solution is easy to be promoted in the treatment of isolated limb in clinical work.