An Experimeal Study On The Transdifferentiation From Epidermal Stem Cells To Corneal Epithelial Cells

Epidermis is an important part of skin, composed of basal lamina, stratum spinosum, granular layer, stratum lucidum, horny layer. Previous investigations use [3H] thymidine to evaluate label retention in epidermis, discoverd that the majority of label retaining cell (LRCs) in the basal lamina of the skin, account for about 10% of the basal cells. These cells have slow periodicity character and the ability of self -renewing, pluripotent differentiation; have an important role in the course of neogenesis and renovation of the skin, so termed as epidermis stem cells (ESCs). At present, people universally accepted the location of ESCs; the techniques of culture in vitro have great progresses, establish the basic for the study of biologic characters and the appliance in the tissue engineering. In this report, we obtained ESCs with higher purification by adhering to Type IV Collage and cultured in serum-free keratinocyte medium, containing low calcium concentration. The biological character, proliferating ability, specific markers expression and differentiation potential of ESCs in culture was discussed. Furthermore, the expression of markers in situ confirmed that the obtained cells were ESCs.Cornea is the important part of eye refraction, which was easily destroyed because of external factor invasion. Corneal transplant is only effective method of curing corneal blinding at present. From the establishment of corneal library, artificial cornea to the development of tissue engineering cornea, the treatment outlook of corneal defect is opened up. In spite of corneal limbus stem cells used as seeds cell in many researches, the limits of cells resource confined their application. For the past few years, a great deal of experiments authenticated that somatic stem cells have the potential of transdifferentiation. In the recent research, the ESCs were capable of differentiation to not only epidermis, but also other tissular cells in specified conditions. The direction of differentiation was regulated by the microenvironment of the stem cells.Stroma cells secrete many factors,such as EGF,NGF,IGF,TGF,which form network adjustment to directional differentiation of cells.In our experiments, corneal stroma was used as inducement environment, while transwell was...