SDF-1 Expressing Human Placenta Derived Mesenchymal Stem Cells For Wound Healing In Nude Mice

Objective:The aim of this study was to evaluate the effects of stromal cell-derived factor 1?SDF1?expressing human placenta derived mesenchymal stem cells?hpMSCs?in a mouse model of wound healing.Methods:After isolation and characterization of mesenchymal stem cells from the placenta,cells were identified by immunofluorescence,flow cytometry,Von kossa staining and oil staining.The cells were infected by lentivirus expressing human SDF-1,and Western blotting and enzyme-linked immunosorbent assay?ELISA?were used to confirm the expression of human SDF-1 of the cells.Then the stably transfected cells were selected as follow-up experimental cell source.60 male female nude mice were selected and the body weight was 160-180g.The mice were randomly divided into control group,hpMSCs group?hp group?and SDF-1 expressing hpMSCs group?SDF-1 group?.Each nude mouse was created a full-thickness skin damage?around 8mm?in the middle of the back by using a punch.Collagen fragments pre-soaked in 400 ng human recombinant CXCR4 were covered onto each wound,Then the wound was wrapped with Tegaderm.At the sam tiam,the control group was injected via tail vein with 0.9%Nacl,hp group was injected via tail vein with 1×106hpMSCs,and SDF-1 group was injected via tail vein with1×106 SDF-1 expressing hpMSCs.The wound was photographed on the 2^nd,5^th,8^th day after cell transplantation.On the 8^th day cut the wound tissue including the whole wound and its surrounding 5mm full-thickness skin,and HE staining sections were made to observe the organization and then epithelialization,blood vessels,tissue regeneration.Tunel staining was used to count the apoptotic status.All the animals were sacrificed by intraperitoneal injection of 10%chloral hydrate on the 8^th day.At the end of the experiment,the transwell system and the macroscopic wound healing model were used to evaluate the cell migration ability and wound healing ability respectively.Results:SDF-1 expressioning hpMSCs has better cell migration ability in Transwell system in vitro;the ability of wound healing of SDF-1 group was significantly better than the other two groups;and Tunel experiments showed that the cell apoptosis rate of SDF-1 group is much lower than the other two groups.Conclusion:The ability of trauma repair of hpMSCs is outstanding.The hpMSCs transfected with SDF-1 were better able to accumulate in the lesion due to their chemotactic ability to CXCR4,so it can accelerate wound healing.This experiment has achieved good results in animal model,laying a foundation for clinical application.And its mechanism of action and differentiation ability still need further experimental proof.