ANALYTICAL STUDIES OF HAIR GROWTH CYCLE ON THE BASIS OF BEHAVIORS OF FOLLICULAR STEM CELLS.

最近，研究表明，位于毛囊凸起处的毛囊干细胞是一种多能细胞，能够形成毛囊、皮脂腺和表皮，并能迁移到毛囊成为基质细胞并产生毛发。然而，表皮干细胞如何转变为毛囊干细胞以及毛囊干细胞如何转变为毛基质细胞尚不清楚。为了阐明第一个问题，我们将逆转录病毒lac-Z基因导入培养的大鼠足底角化细胞中，获得了多层、lac-Z标记的体外培养上皮。因为标签是在所谓的表皮增殖单位中发现的，我们认为表皮干细胞被标记了。然后，我们将标记的上皮细胞与触须真皮乳头移植，观察标记干细胞如何参与毛囊的诱导过程。到目前为止，由于la - z基因在基底层细胞中的表达受到抑制，这些标记仅在再生表皮和诱导卵泡的分化细胞中发现。我们研究了第二个问题，从毛发生长周期不同阶段的毛囊中解剖出毛球，并将其移植到同基因大鼠肾囊下。我们从移植物中连续的毛球重建和毛发生成的模式推断出基质细胞祖细胞的迁移过程。结果表明，毛囊干细胞在毛发生长周期内并没有从毛囊突起持续募集到毛球，而在毛囊生长后期和毛囊生长后期也没有募集到毛囊干细胞。

Recently, it has been shown that follicular stem cells located in the bulge are multipotent cells capable of forming hair follicles, sebaceous glands and epidermis, and that they migrate to the hair bulb to become matrix cells and produce hairs. However, it has not been clarified how the epidermal stem cells become follicular stem cells and how the latter behave to become hair matrix cells.In order to elucidate the first problem, we introduced retro-viral lac-Z gene into cultured rat sole keratinocytes and got multi-layered, lac-Z-labeled cultured epithelium in vitro. Because the labels were found in so-called epidermal proliferation unit, we thought epidermal stem cells were labeled. Then we transplanted the labeled epithelium with vibrissa dermal papillae and observed how the labeled stem cells participated in the process of hair follicle induction. So far, it was demonstrated that the labels were only found in the differentiated cells of the regenerated epidermis and the induced follicles because of the suppression of lac-Z gene expression in the basal layer cells.We investigated the second problem by dissecting out hair bulbs from vibrissa follicles at different stages of hair growth cycle and transplanting them under the kidney capsules of syngeneic rats. We deduced the process of migration of matrix cell progenitors from the pattern of successive hair bulb reconstruction and hair production in the grafts. It was strongly suggested that follicular stem cells were not continuously recruited from the bulge to the hair bulb during hair growth cycle but they were not recruited between late anagen and late catagen.