ABSTRACT
【Objective】 To investigate the effects of neutrophil-derived exosomes on skin wound healing. 【Method】 ① The venous blood was taken from 10 healthy volunteers to separate and purify neutrophils, and exosomes were prepared from neutrophil supernatants using differential centrifugation on Sepharose columns. ② The rat trauma model with full-thickness skin defect was prepared and randomly divided into three groups: control group, 50 μg/mL exosomes group, and 100 μg/mL exosomes group. The CCK8 test and the scratch test were used to determine the proliferation and migration of vascular endothelial cells, respectively, which was used to investigate the effects of neutrophil-derived exosomes on the formation of endothelial cell tubular structures in vitro. On day 7 and day 14 after surgery, the skin wound healing was observed and the wound healing rate in different treatment groups was compared. On day 14 after surgery, the wound tissues of each group were stained with HE and Masson to observe the arrangement of collagen fibers. 【Results】 ① Neutrophil-derived exosomes were round or oval vesicles with diameter about 100 nm. ② On post injury hour (PIH) 12, the scratch test suggested that wound healing rates in the three groups were close (P>0.05 ), while wound healing rate of 100 μg/mL neutrophil-derived exosomes in the treatment group was higher than that in the control group (P<0.01) and 50 μg/mL exosomes group (P<0.05) on PIH 24. On PIH 12, the result of CCK8 assay showed that 50 and 100 μg/mL exosomes groups had enhanced proliferative activity of vascular endothelial cells (P<0.01) and the results were still higher in both groups than in the control group on PID 24. The results of tube formation assay showed that neutrophil-derived exosomes could promote the formation of tubular structures of endothelial cells in vitro (P<0.01). ③ On day 7 and 14 after surgery, compared with the control group, the wound healing rates of the 50 and 100 μg/mL exosomes groups were higher (P<0.01). The wound healing rate of 100 μg/mL exosomes group was higher than that of 50 μg/mL exosomes group (P<0.01). Compared with the control group, the newly formed epidermis and dermis on the wound surface of the 100 μg/mL exosomes group were longer, the number of collagen fibers increased, and the arrangement direction was highly consistent on the 14 th day after surgery. 【Conclusions】 Neutrophil-derived exosomes can promote full-thickness wound healing in rats by promoting the proliferation and migration of new vascular endothelial cells and the formation of collagen fibrous.