Construct Tissue Engineering Skin With Hair Follicle By Hair Follicle Cells

With the rapid advancement in the technology of tissue engineering (TE) over the years, TE skin has seen extensive application in clinic. At present, the main origin of seed cells of TE skin is usually dermal fibroblasts and keratinocytes. In consequence, there exist profound differences between normal skin and TE skin, with the later having no skin adnexa, such as hair follicle, sebaceous gland and sweat gland and so on.Hair follicles play a very important role in skin wound healing, serving as origins of seed cells. However, until now, documents or reports on constructing TE skin with hair follicle cells are scarcely found in China as well as in the world. In this study, the researcher firstly separates in vitro outer root sheath cells, dermal sheath cells and dermal papilla cells of hair follicle, and then uses outer root sheath cells and dermal sheath cells as seed cells to culture a new type of TE skin. The new type TE skin is grafted to nude mice to test the biological activity. Meanwhile, efforts have been made to explore TE skin with adnexa. The experiment is specified as follows:1. Vibrissas in anagen stage of newly born SD rats serve as cell sources. Dermal sheath cells and outer root sheath cells are obtained through digestivemethod and dermal papilla cells are obtained by culturing the intact dermal papillas. hi these studies, large numbers of well-cultured outer root sheath cells, dermal sheath cells and dermal papilla cells are cultured in easy and fast ways.2. Using the technology of full-thickness TE skin culture in our laboratory, TE dermis constructed with dermal sheath cells is cultured firstly. Then, intact hair follicles are implanted into the TE dermis. After 10-day culturing, double-layer TE skin is developed. Another type of TE skin is constructed with dermal sheath cells and outer root sheath cells. These two kinds of TE skin are grafted into the full-thickness skin defects of nude mice, so is the TE skin that was cultured by skin dermal fibroblasts and keratinocytes. The curative effect among them is compared. All these TE skin can repair the full-thickness skin defects and have the structure of dermis and epidermis. But there are much more micrangiums in dermis and no ulcers in epidermis of the former two kinds of TE skin when the skin recovered. This study demonstrates that dermal sheath cells and outer root sheath cells instead of skin dermal fibroblasts and keratinocytes can be used to construct TE skin, and this new type of TE skin can repair skin defects more effectively.3. Construction of TE skin with hair follicles in vitro: Using the technology of full-thickness TE skin culture in our laboratory, TE dermis constructed with dermal sheath cells is cultured firstly, then intact dermal papillas or dermal papilla cell masses are embedded into the collagen gel and then outer root sheath cells are planted onto the surface of the collagen gel. After grafting to nude mice both, the grafted skins are biopsied and stained with hematoxylin-eosin (HE) or immunohistochemical methods. The histopathological findings demonstrate that structures like hair follicle or sebaceous gland grow in dermal papilla cell masses group's dermis, whill there are hair follicles and sebaceous glands as normal in intact dermal papillas group.To sum up, TE skin with hair follicles was developed successfully. It turns out...