Effects of human umbilical cord mesenchymal stem cells in the treatment of diabetic wound, survival and colonization in vivo

Objective To investigate the effects of human umbilical cord mesenchymal stem cells (hUC-MSCs) in the treatment of diabetic wounds in nude mice, and to observe the survival, colonization and differentiation of hUC-MSCs. Methods Diabetic nude mice were induced by intraperitoneal injection of STZ, and a 1.5 cm×1.5 cm diameter wound was cut from the back of the nude mice. Then, hUC-MSCs were treated with CM-Dil stain and transplanted into the wound of nude mice. The morphological changes were observed to calculate the wound healing rate. The fluorescence flux of hUC-MSCs on the wound surface of nude mice after injection after 0 h, 12 h, 1 day, 2 days, 7 days and 14 days was measured by the small animal live imaging system. The skin at the base and edge of the wound of the nude mice were taken at the corresponding time points, and the distribution and survival of the transplanted cells in the skin were observed under a fluorescence microscope. On the 14th day after injection, the heart, liver, spleen, lungs, kidneys, brain and other tissues of the nude mice were taken, and the distribution of hUC-MSCs was observed under a fluorescence microscope. Results Compared with the control group, hUC-MSCs significantly promote wound healing. After hUC-MSC transplantion, the small animal live imaging system showed that the fluorescence of stained hUC-MSCs was concentrated around the wound surface and migrated to the base of the wound surface. The concentration was the highest 24—72 h after transplantation, and then the number of the cells rapidly decreased. After 14 days of transplantation, no hUC-MSCs were found to survive within the mice. Conclusions hUC-MSCs can promote wound healing in nude mice, and the local concentration of hUC-MSCs is the highest 24—72 h after transplantation. However, hUC-MSCs cannot colonize and differentiate in animals for a long time.