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The growth of human cells in the environment of the body to provide micro-dynamics, mechanical stress can not only cause the cell morphology, structural changes, but also regulation of the functional state of the cell, affecting cell proliferation, differentiation and apoptosis in certain physiological and pathological processes plays an important role. It has been proved that the mechanical stress can promote cell proliferation and differentiation, by factors external stimuli \Traction lengthening surgery such as orthopedic limbs, the pressurized fracture fixation, craniofacial surgery craniofacial traction orthopedic dilation of the skin and soft tissue (skin soft-tissue expansion, SSTE). Studies show that significant heterogeneity in different types of cells, the effect shown by the same stress stimulation is different, and the same cell is also different for different stress response, therefore, the results of the other fields of research is difficult to guide particular field clinical practice. Ongoing active field of basic research is mainly concentrated in the bone cells (study stress osteoblasts), vascular smooth muscle cells (high blood pressure), vascular endothelial cells, mesangial cells (research glomerular hypertension) , as well as lung epithelial cells, the research literature related to SSTE has rarely been reported. No stress and epidermal stem cells (epidermal stem cells, ESCs) relevant literature. Since 1976, Radovan invention controlled dilator, SSTE has been widely used in clinical benefit tens of thousands of patients, and has now become one of the means of conventional orthopedic treatment. SSTE after 30 years of development, in experimental research, clinical applications, expansion methods, prevention of complications, and many other aspects has made considerable progress, however, the expansion cycle is longer, more complications shortcomings still yet more of this on to get resolved. Therefore, how to shorten the time of expansion, reduce complications become SSTE research areas of focus problem. It has been proved that the expansion produced \may overcome these problems lies, but so far, the proliferation and differentiation of behavior of skin cells in the expansion process is not yet very clear. ESC as skin tissue-specific stem cells, not only to maintain the main function of the skin daily metabolic cells, and is also closely related to wound repair. But the relationship is still little known about the specific role played by ESC SSTE process, or with skin expansion. To this end, in-depth understanding of the distribution of the ESC SSTE process, proliferation and differentiation characteristics and related regulatory mechanism, no doubt enrich perfect SSTE basic theory, and more perfect guide clinical application SSTE has an extremely important significance. To this end, the study was observed to in vitro and in vivo two means to carry out the following experiment: the use of epidermal stem cells and their proliferation during the differentiation of different cell surface markers, as well as the characteristics marked proliferation of cells proliferating cell nuclear antigen (PCNA) using immunohistochemistry chemical method observed expansion process with the proliferative capacity of epidermal stem cells, transient expansion of cell distribution and the number of differences, a preliminary observation of skin expansion epidermal stem cell proliferation differentiation of, can be further study of epidermal stem cells in the skin expansion of the role. In addition, the cells cultured in vitro with the mechanical stress, studied under stress after various changes, is a very rapid development of the field of cell biology methods. Epidermal stem cells were isolated and cultured people, to establish a viable compressive stress in the cell culture system device, observe and research compressive stress on the proliferation and differentiation of epidermal stem cells. [Objective] To observe the rats in vivo skin soft tissue expansion of its expansion in the epidermal cell proliferation and differentiation characteristics and intermittent compressive stress on the proliferation and differentiation characteristics of epidermal stem cells in vitro and to explore its possible mechanism of action. [Methods] 1) 36 Wistar rats produced an animal model of skin expansion and the expansion of the group and the non-expansion were randomly divided into control group. Epidermal stem cells express angle protein (, keratin 19, K19), p63, short-term expansion of cells expressing K14 and proliferating cell nuclear antigen (PCNA) characteristics, respectively, in the expansion process after the expansion is not at the same time phase point, using streptavidin - biotin (SP) immunohistochemical staining characteristics of the distribution of the expanded skin epidermal stem cells and transient amplifying cells, and conventional HE staining expansion change the thickness of the skin epidermis. 2) through our established murine epidermal stem cells in vitro separation cultured conducted human epidermal stem cells in vitro separation, culture, and the use of streptavidin - biological pigment (SP) immunohistochemical chemical staining and cell cycle analysis were identified ; using cultured cells pressurized device is subject to different compressive stress (4kPa, 6kPa, 8kPa, 10kPa, 12kPa) pressure of epidermal stem cells using cell-specific expression of epidermal stem keratin 19 and cytokeratin 10, terminally differentiated cells, streptavidin - biotin (SP) immunohistochemical staining pressure before and after the changes of epidermal stem cells and terminally differentiated cells. [Results] 1) expansion of the skin epidermis was significantly thicker, not only the basal layer of K19, p63, K14, and the number of PCNA-positive cells increased significantly, and in the spinous layer and granular layer visible K19, p63, K14 and PCNA-positive cells expression; 2) separation of epidermal stem cells cultured K19 immunohistochemistry staining positive cell cycle analysis 84.80% of the cells in the G 1 of; the more intermittent pressure 8kPa stress adhesion to the silicone membrane epidermal stem cells after one week, the number increased significantly, immunohistochemical staining keratin 10-positive cells. [Conclusion] This study found that the stress of the skin and soft tissue expansion can be induced epidermal stem cell proliferation and differentiation, the process of skin expansion both stress-induced proliferative effect, another stress injury caused by micro-start the wound healing effect, is atypical of wound repair pathological physiological process, this process has the self-renewal, unlimited proliferation potential and regenerative repair capacity of epidermal stem cells play an crucial role; same time also confirmed 8kPa over the intermittent compressive stress can be induced epidermal stem cell proliferation and differentiation. further prompted epidermal stem cells to mechanical stress response mechanism \
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