[EXPERIMENTAL STUDY ON HUMAN UMBILICAL CORD MESENCHYMAL STEM CELLS-ALGINATE WOUND DRESSING]

To observe the growth characteristics of human umbilical cord mesenchymal stem cells (hUCMSCs) cultured on the alginate gel scaffolds and to explore the feasibility of hUCMSCs-alginate dressing for wound healing.

hUCMSCs were separated from human umbilical cords and cultured in vitro. After the 4th passage cells were co-cultured with alginate gel (experimental group), the cell growth characteristics were observed under the inverted phase contrast microscope. Vascular endothelial growth factor (VEGF) content was measured and the number of cells was counted at 0, 3, 6, and 9 days after culture; and the cell migration capacity was observed. The hUCMSCs were cultured without alginated gel as control. The model of full-thickness skin defects was established in 32 8-week-old Balb/c male mice and they were randomly divided into 4 groups (n=8): wounds were covered with hUCMSCs-alginate gel compound (MSC-gel group), cell supernatants-alginate gel compound (CS-gel group), 10% FBS-alginate gel compound (FBS-gel group), and 0.01 mol/L PBS-alginate compound (PBS-gel group), respectively. Wound healing rates at 5, 10, and 15 days were observed and calculated; and the wound tissues were harvested for histological and immunohistochemical staining to assess new skin conditions at 15 days after operation.

hUCMSCs grew well with grape-like proliferation on the alginate gel, but no cell migration was observed at 7 days after cultivation. VEGF expression and cell number in experimental group were significantly less than those in control group at 3 days (P<0.05); then they gradually increased, and VEGF expression and cell number were significantly more than those in control group at 9 days (P<0.05). The wound healing rates of MSC-gel and CS-gel groups were significantly higher than those of FBS-gel and PBS-gel groups at 5, 10, and 15 days (P<0.05). The squamous epithelium, fibroblasts, sebaceous glands, capillaries and VEGF expression of the new skin in MSC-gel and CS-gel groups were significantly more than FBS-gel and PBS-gel groups (P<0.05). But there was no significance between MSC-gel and CS-gel groups (P>0.05).

hUCMSCs can continuously express VEGF in alginate gel, which is necessary for wound healing. The hUCMSCs-alginate compound is probably a good wound dressing.