Intravenous transplantation of bone marrow mesenchymal stem cells could effectively promote vascularization and skin regeneration in mechanically stretched skin

Skin expansion is a procedure that stimulates and promotes skin regeneration by applying continuous mechanical stretching. However, the outcome of treatment is limited by the skin's instinctive regeneration capacity.To evaluate the impact of intravenous transplantation of bone marrow mesenchymal stem cells (MSCs) on expanded skin regeneration.MSCs from luciferase-Tg Lewis rats were transplanted into a rat tissue expansion model and tracked in vivo by luminescence imaging. At the end of 21 days of skin expansion, the expanded skin was harvested and skin regeneration was evaluated by inflation volume, skin area and thickness. Counting of capillaries and vascular endothelial cell growth factor (VEGF) expression analysis were conducted to assess the impact of MSCs on expanded skin vascularization.Samples of the skin expansion model from the MSC group were observed to have a significantly higher inflation volume and greater expanded skin area than those from the control group at the end of 21 days' follow-up. In vivo tracing results showed that MSCs were recruited by mechanical stretch and migrated to expanded skin. Migrated MSCs promoted skin vascularization by secreting VEGF and differentiating into CD31+ endothelial cells. Skin sections from the MSC group had a significant advantage in thickness and proliferating cell count, indicating that MSCs effectively enhanced expanded skin regeneration.Intravenous transplantation of MSCs could effectively promote expanded skin regeneration. Transplanted MSCs could be recruited by mechanical stretch and subsequent migration to expanded skin. Engrafted MSCs could contribute to vascularization and cell proliferation.