Bone Marrow Mesenchymal Stem Cells Improve Swine Cutaneous Wound Repair

Objective:To explore the effect of swine Bone marrow mesenchymal stem cells (BMSCs) and whether it can improve the quality of wound repair of a swine full-thickness skin wounds under particle skin or small skin autografts environment and it's possible mechanism. Thus provide a new therapy and methods for clinical burn wound and cutaneous wound repair.Method:A male and a female Diannan small-ear swine which were supplied by the Experimental Animal Center of Kunming Medical University, experimental animals permit number SYXK2005-004. Harvest the bone marrow by density gradient centrifugation to extract BMSCs and cell culturing in vitro. Then amplify and purify the3─5generation BMSCs to prepare for further experiments. A total of48wounds, there are12full-thickness skin wounds on each side of each swine spine, also in each experimental group and control group. Experimental group:A: Autologous particle skin transplantation+BMSCs; B: Autologous small skin graft transplantation+BMSCs; C:BMSCs. Control group:a: Autologous particulate skin transplantation; b: a small skin autograft; c:PBS. The1,2,3,4week time after surgery, do histopathology to evaluate its histopathological classification, immunohistochemistry (IHC) to staining collagen type I and III, real-time PCR detection to analyze the mRNA expression level of TGF-β1,TGF-β3,collagen type I and III.Result: Histopathology survey found that after the1,2,3,4week time of surgery, compared to the control group (a, b group),the experimental group (A, B group) was better than the control group which has the statistically significant differences from the level of wound repair of the histopathology evaluation(P<0.05). Real-time PCR test results suggest that collagen type Ⅰ and Ⅲ mRNA are higher at the experimental group(A, B group) after the surgery compared to the control group(a,b), the ratio of Ⅰ/Ⅲ collagen of the experimental group (A, B group) is lower than the control group (a, b group). The expression level of TGF-β1mRNA experimental group (A, B, C group) compared with the control group (a, b, c group) is continued to decrease (P <0.05) after the operation; the expression of the experimental group and control group has no significant statistical difference at week3and4(P>0.05). TGF-β3mRNA expression of the experimental group was significantly higher than the control group (P<0.05) at week2,3,4after the operation.Conclusion:1,BMSCs transplant can promote the survival of particle skin and small skin grafts.2,BMSCs regulate the secretion of TGF-β1,TGF-β3, which improve cutaneous wound repair.3,BMSCs upregulate the secretion of type Ⅰ,Ⅲ collagen and decrease the ratio of Ⅰ/Ⅲ collagen, which is the possible mechanism of how BMSCs improve cutaneous wound repair.4. BMSCs alone can not replace the conventional way of Autologous particle skin and small skin graft transplantation.