Objective      To investigate the effect of human umbilical cord mesenchymal stem cells (hUC-MSCs) on wound healing and the expression of vascular endothelial growth factor (VEGF) after full-thickness excision dermal wounds in mice.       Methods      hUC-MSCs were isolated from the human umbilical cord tissues from a full-term neonate by tissue explants adherent method

and then cultured and identified with flow cytometry for cellular immune phenotypes. Then the obtained hUC-MSCs were induced to differentiate into osteoblasts and adipocytes. Forty-eight male BALB/c mice were randomly divided into hUC-MSCs group and PBS group

with 24 animals in each group. The mice were injected with hUC-MSCs suspension and PBS fluid respectively around the wounds which were made as a full-thickness excision skin wounds in size of 1.5 cm on the dorsum in mice. The wound healing condition were examined in 3

7

and 14 d after operation

and pathological changes were observed with HE staining. The protein expression of VEGF were detected with immunohistochemical assay and Western blotting.       Results      Flow cytometry results showed that the cultured cells was hUC-MSCs

and the obtained cells could be induced to osteogenic and adipogenic cells after differentiation. The wound healing rate was obviously higher at all time points in the hUC-MSCs group than the PBS group (P0.05). HE staining indicated that the wound healing quality was better in the former than the latter group. Immunohistochemical assay displayed that the expression level of VEGF reached the highest in wound at 3 d

and then reduced gradually at 7 and 14 d in the hUC-MSCs group

but still significantly higher than in the PBS group. Western blot assay showed that the protein expression level of VEGF was obviously higher in hUC-MSCs group than in the PBS group at 3

7

and 14 d after operation (P0.05).       Conclusion      hUC-MSCs promote the expression of VEGF and facilitate the healing of skin wound.