Epidermal growth factor promotes mesenchymal stem cell-mediated wound healing and hair follicle regeneration

Background and Aim: Bone marrow mesenchymal stem cells (MSC) are receiving increasing attention for skin wound repair. However, the specific mechanisms underlying MSC-mediated improvement in wound healing have not been fully elucidated. This study aims at testing whether epidermal growth factor (EGF) can promote MSC-mediated wound healing and hair follicle regeneration. Methods: Excisional wounds in rats were transplanted with different collagen-chitosan scaffolds: control, MSC, and MSC + EGF. Regenerated tissues were harvested 1, 3, or 5 weeks following transplantation, stained with hematoxylin and eosin and evaluated microscopically. The formation of sebaceous glands was examined by Oil red staining and the regeneration of hair follicles by immunohistochemical staining and Western blot to test the expression of hair follicle-specific factors. Results: Gross observations showed that the wounds were much smaller and the hairs grew faster in the MSC + EGF group. Histological analysis demonstrated that there were more hair follicles, sebaceous glands, and newly formed blood vessels in the MSC + EGF group compared with that in the MSC group. In addition, oil red staining showed that MSCs + EGF induced sebaceous gland regeneration. Finally, immunohistochemistry and western blot revealed that MSCs + EGF increased the expression of hair follicle-specific factors. Conclusion: MSCs alone cannot achieve the regeneration of hair follicles and EGF can promote MSC-mediated wound healing and hair follicle regeneration.