Investigation Of The Possibility Of The Hair Follicle Induction By Dermal Papillae Cells And Bulge Cells

Recently, with the development of the tissue engineering (TE), remarkable achievements have been made in the clinical applications of TE skin. Hair follicle (HF) is a specialized skin appendage, and it is to protect our bodies from the elements, helps regulate heat and is a sensory item. Thus HF has been studied a lot.HF is composed of epidermal and dermal, and interactions between hair follicle epithelial and dermal cells are necessary for hair follicle morphogenesis during development and in hair reconstitution assays. The cells in bulge are described as the epithelial stem cells in HF for their slow cell cycle, superior clonogenicity and proliferative capacity. In tissue engineering they will be no doubt good resource of stem cells. While at the other hand, dermal papillae cells (DPCs), which are mesenchymal and reside in the dermal papillae (DP) of the HF, show high hair-inductive property. In our study, bulge cells (BCs) and DPCs were collected from rat vibrissa follicles, and then reunited as cell masses in a certain form after being cultured in vitro. Cell masses were then implanted in vivo to explore their ability of regenerating hair follicle. Our conclusions are summarized as follow:1, the culture and identification of the DPCsVibrissa follicles were excised from the upper lip of SD rats. DPs were removed from the anagen follicles using a fine needle and a pair of forceps. It took about a week for the outgrowths of cells from DP explants. Cultured DPCs were fibroblast alike and showα-SMA and vimentin positive, which tells that the cells collected and cultured were from mesenchymal tissue. The ALP activity detected indicated the hair-inductive property of the DPCs.2, the culture and identification of the BCsSurgical micro-dissection was used for vibrissa follicle collection. HFs were then treated with dispase so the out root sheath (ORS) could be easily separated from the dermal sheath. The bulge area was further isolated from the ORS and cultured in vitro. PCR shows the BCs were positive for keratin 15 as well as for keratin 19.3, combination of the DPCs and the BCs, and the investigation of their hair-inductive propertyCultured BCs were encapsulated in fibrin glue and then buried in typeⅠcollagen mixed with cultured DPCs. After 24 hours'culture in vitro, this compound cell mass was then implanted under the renal capsule of SD rat. 2 and 3 weeks later, hair follicle like structures were found in the cell mass.4, the impact of Wnt3a on the DSCsDSCs were isolated from HFs and cultured in vitro with culture medium which had been added Wnt3a to, 48 hours later, no obvious change was found in the expression of ALP, however, the level of CD34 quantity became higher. We guess that Wnt3a has nothing to do with the increase of hair inductive property but may have some influence on tumorigenesis in the hair follicle.In summary, we concludes that the method used in this experiment has the potential for reconstructing hair follicle, and this contributes to the research on construction of tissue engineering skin with hair follicle.