Allotransplantation Of BM-MSCs/GPF Made Deep Skin Wound Regeneration

ObjectivesTo investigate the relationship between the regeneration or scarring of skin wound and depth of injury to explore whether BM-MSCs/GFP transplantation could help deeper skin wound regenerate and its possible cellular and molecular mechanism.MethodsThe gradually deepening skin wound model, from epidermis to hypodermis, was established on the back of SD rat. The third generation of SD rat BM-MSCs/GFP was diluted with PBS to get a cell suspension of 1.0×10~6/300.0μL; among them, 200.0μL were equably injected into wound edges and the other 100.0μL into wound surface. In control group, the equal volume of PBS were injected according to previous method. The pictures of the wounds in 1,3,5,7,14 and 21 days after transplantation and then total wound along with its surrounding normal skin were harvested at different time points to observe the changes in numbers and distribution of grafted BM-MSCs/GFP,and to confirm the deepest layer of wound regeneration in both groups through pathological section and Immunohistochemistry. According to the Immunohistochemistrical results of Blimp1~+and Lgr6~+ stem cell and VEGF expression variation, the possible mechanism of wound regeneration was studied. The rate of wound contraction, wound recovery, the numbers of grafted BM-MSCs/GFP and percentage of stained cells in Immunohistochemistry at different time-point were assessed by two way ANOVA. The numbers of vessels were analyzed by Dunnet t test. The deepest regeneration layer of wound was assessed by Χ~2 test. Datum were analyzed using SPSS10.0 software; P<0.05 was considered significantly different.ResultsInjury above the level of infundibulum apex regenerated without scar formation in control group. In experimental group, with the transplantation of BM-MSCs/GFP, the deepestregeneration layer of wound reached the level of sebaceous opening at hair follicle. The number of grafted BM-MSCs/GFP decreased over time, and remained less than 1% of first time-point on21 th postoperative day. The grafted BM-MSCs/GFP migrated to different layers of the wound including sebaceous glands and vessels, then disappeared on 21 th postoperative day. The number of Blimp1~+and Lgr6~+ stem cells started to increase on 3d and 5th postoperative day respectively,and it was significantly higher in BM-MSCs/GFP group than that in control group(P<0.05),there were no significant difference on 21 th postoperative day.The expression of VEGF in BM-MSCs/GFP group was higher than that in control group before 5th postoperative day(P<0.05).The number of vessels increased from 2.5 ± 0.2/phf of control group to 5.0 ± 0.3/phf of BM-MSCs/GFP(P <0.05).ConclusionsTopical transplantation of BM-MSCs/GFP significantly improved regeneration layer of deep wound from infundibulum apex to sebaceous opening level of gland at hair follicle. Though the grafted BM-MSCs/GFP could not survival for long time, its exist within wound at early stage was helpful to the repair of sebaceous gland and activation of Blimp1~+and Lgr6~+ stem cell. The improvement of wound regeneration resulted from the co-operation of grafted BM-MSCs/GFP and self stem cells of receptor.