ObjectiveTo explore the phenotypic changes of epidermal stem cells (ESCs) differentiating into sweat glands cells (SGCs) in vitro and its mechanisms. MethodsESCs and SGCs were isolated and cultured in vitro, which were identified using immunofluorescence staining. ESCs at passage 2 were divided into 4 groups: ESCs and SGCs co-cultured by Transwell plates in group A, ESCs cultured by simply adding sweat supernatant in group B, ESCs and SGCs co-cultured on Transwell plate adding epidermal growth factor (EGF) (60 ng/mL) in group C, and ESCs and SGCs co-cultured on transwell plate adding PD98059 (10 mmol/L) in group D. The inverted microscope was used for observing the morphology of ESCs, flow cytometry for detecting ESCs positive phenotype, and Western blot for exploring mitogen-activated protein kinase/extracellular signal regulated kinase (MAPK/ERK) pathway. ResultsThe morphology observation and immunofluorescence staining suggested that cultured cells were ESCs and SGCs. The inverted phase contrast microscope observation showed that cells had similar morphological changes, with flat polygonal shape at 9 days in groups A, C, and D; cells had slow morphological change in group B, and had similar change to that of other groups at 12 days. Significant decreasing of β1-integrin expression and increasing of carcino-embryonic antigen (CEA) expression of ESCs were observed in group A when compared with group B, which was inhibited by EGF (group C) and enhanced by PD98059 (group D), and there were significant differences among groups A, C, and D (P<0.05). High level of ERK expression was displayed in 4 groups, but it was significantly lower in group B than the other 3 groups (P<0.05). The expression of phosphorylation ERK was the highest in group A and was the lowest in group C, showing significant difference among 4 groups (P<0.05). ConclusionESCs can be induced to differentiate into SGCs with the phenotypic changes under the condition of co-cultured by Transwell plates. The MAPK/ERK pathway plays a key role in the differentiation of ESCs into SGCs.