Abstract: Objective To observe the ability of cultured dermal papilla cells(DPCs) to induce hair follicle regeneration and to sustain hair growth in vivo and in vitro.Methods The expression of basic fibroblast growth factor (bFGF),endothelin-1 (ET-1) and stem cell factor (SCF) in different passages of DPCs,and their possible effects on biologic behaviour of DPCs were measured by in situ hybridization and immunohistochemistry.Hair follicle regeneration induced by DPCs in hair follicle organotypic culture model and the model implantated into nude mice were studied.Results The expression of ET-1 and SCF in the early passages of cultured DPCs was strong,but became weak and even negative after 6 passages.Hair follicle-like structures were formed in the hair follicle organotypic cultures,composed of DPCs and hair follicle epithelium cells.When the hair follicle organotypic cultures were implanted into the subcutis of nude mice,relatively intact hair follicles were formed.Injection of the early passage DPCs mixed with hair follicle epithelial cells into the subcutis of nude mice resulted in the formation of hair follicle-like structures,while the structures were not formed after the injection of the mixture of hair follicle epithelial cells with dermal sheath fibroblasts or with scalp fibroblasts.There was a positive correlation between the expression levels of ET-1 and SCF in DPCs and the ability of DPCs to induce hair follicle regeneration.Conclusions Cultured DPCs can induce hair follicle regeneration and sustain hair growth in vivo and in vitro.Moreover,the expression levels of ET-1 and SCF are positively correlated with the ability of DPCs to induce hair follicle regeneration.

Key words: Hair follicle, Cells,cultured, Regeneration