Umbilical Cord Mesenchymal Stem Cell Derived Exosomes Promote Hair Growth In Androgenetic Alopecia Model Mice Through RAS/ERK Pathway

Objectives:Androgenetic alopecia,the most common type of hair loss,has become a medical and social problem due to its increasingly younger onset.Existing treatments,although effective,have serious side effects.Therefore,better treatment methods are needed.This study aims to evaluate the efficacy of umbilical cord mesenchymal stem cell-derived exosomes in the treatment of androgenetic alopecia,and to explore the mechanism of hair growth regulation by exosomes.Methods:First of all,20 C57BL/6J mice were randomly divided into blank group,model group,positive control group and exosome hydrogel group.The back of the mice was depilated,and except for the blank group,the other mice were intraperitoneally injected with dihydrotestosterone to establish androgenetic alopecia models.At the same time,the model mice were intervened with exosome-encapsulated hydrogel to evaluate the effect of exosomes on promoting hair growth.At the end of the experiment,the neonatal hair of mice was collected to compare the differences in the length,diameter and number of hair follicles in each group.HE staining was used to observe the pathological changes of hair follicles.The m RNA and protein expression of androgen receptor in skin tissue were compared.real-time PCR,western blotting,immunofluorescence staining,and transcriptome sequencing analysis were performed on skin tissues.Finally,the results of transcriptome sequencing were verified by real-time PCR,western blotting and other technologies.Results:Compared with the blank group,the hair length of the model group was shortened,the hair diameter was reduced,the total number of hair follicles was significantly reduced,and the hair follicles were miniaturized.Compared with the model group,the length of newborn hair in the positive control group and the exosome group increased,the diameter of hair increased,and the number of hair follicles increased.The m RNA and protein expression of androgen receptor in the skin tissue of the model group were significantly higher than those of the blank group,and the histone expression of androgen receptor in the exosome gel was lower than that of the model group.Similarly,compared with the model group,the fluorescence expression of hair follicle stem cell-related proteins K15 and CD200 in the exosome group increased.The expression of cell proliferation-related protein PCNA increased.Transcriptome sequencing results suggested that compared with the model group,the differentially expressed genes in the exosome group were mainly enriched in cell transduction function.KEGG analysis showed that the differentially expressed genes were mainly enriched in RAS/ERK pathway.Conclusion:This study confirmed the therapeutic effect of HUCMSCs derived exosomes on androgenetic alopecia,and verified that exosomes regulate the stemness of hair follicle stem cells through the RAS/ERK pathway,promote the proliferation of hair follicle cells,and promote hair growth in androgenetic alopecia mice,which provides a potential treatment strategy for androgenetic alopecia.