ヒト培養毛乳頭細胞に対するin vivo毛包誘導能評価系の確立への試み

摘要

Dermal papilla cells (DPCs) in mammalian hair follicles have been shown to have the ability to induce and develop hair follicles.It seems to be theoretically possible to regenerate human hair by expanding DPCs and transplanting them into bald skin.Since the viability of DPCs for hair induction becomes weaker through a long period of cultivation, it is a key to success in 'hair regenerative therapy' to elucidate factors that maintain the intrinsic viability for hair induction. Thus, there is a great need for a simple and reliable assay, either in vivo or in vitro, to study hair induction by DPCs. Therefore, we are seeking the simplest and the most repeatable models for testing the inductive viability of human DPCs. In this study, we examined the reproducibility of two of in vivo models for trichogenesis previously reported, including 'chamber models', grafting cultured human DPCs into silicone chambers on nude mice, and 'sandwich models', implanting cultured human DPCs with rat sole skin under the skin of nude mice. Twenty-six 'chamber models' were prepared out of 13 cell lines of DPCs, and sub-cultivated up to 5 passages. Forty-seven 'sandwich models' were prepared out of 8 cell lines, and sub-cultivated up to 3 passages. New hair follicles were generated in 5 models and 24 models, and the rates of hair induction were 50.0+16.7 % and 56.8.0.6%,respectively. The values of the coefficient of variation were 1.00 and 0.56, respectively.The new follicles generated in the 'sandwich models' were more readily distinguishable and differentiated than those in the 'chamber models' in histological examination. The 'sandwich models' were more useful than the 'chamber models' and other in vivo models for testing the inductive viability of human DPCs in terms of reproducibility.