Matsuzaki T, Inamatsu M, Yoshizato K
Yoshizato MorphoMatrix Project, ERATO, JRDC, Hiroshima, Japan.
Differentiation. 1996 Sep;60(5):287-97. doi: 10.1046/j.1432-0436.1996.6050287.x.
It has been established that the dermal papilla and the lower dermal sheath of a hair follicle can induce a new hair bulb in follicular epidermis. However, the upper dermal sheath has been believed not to have such an inductive capacity. In contrast to this generally accepted notion, the present study claims the inductive capacity of the upper dermal sheath of a rat vibrissa follicle, as pelage-type hairs were autonomously produced in the amputated upper halves of the follicles when implanted under the kidney capsule for 8 weeks. The study with monoclonal antibodies specific to different follicular tissues clearly revealed the regeneration of small hair bulbs in these implants and suggested that the fine hairs were formed as a result of the interaction between the upper dermal sheath cells and the follicular basal cells. Newly formed bulbs located at two separate sites, one at the amputated end and the other in the upper region of the follicles. No bulb was formed near the bulge area where follicular stem cells had been reported to locate. However, the possibility of involvement of the stem cells in the bulb formation remains, as migration and rearrangement of epidermal cells had occurred in the implants. Together with the comparative experiments on the inductive potential of various dermal compartments, the present study showed that the upper dermal sheath possesses a hair-inducing ability which is weak, as compared to the lower dermal compartments, but sufficient to induce the follicular epidermis to differentiate into the pelage-like hair-producing bulb, and would be activated only under this specific condition.
已经证实，毛囊的真皮乳头和真皮鞘下层能够诱导毛囊表皮形成新的毛球。然而，人们一直认为真皮鞘上层没有这种诱导能力。与这一普遍接受的观点相反，本研究表明大鼠触须毛囊的真皮鞘上层具有诱导能力，因为当将毛囊的上半部分植入肾被膜下8周时，会自主产生被毛型毛发。使用针对不同毛囊组织的单克隆抗体进行的研究清楚地揭示了这些植入物中小毛球的再生，并表明细毛是真皮鞘上层细胞与毛囊基底细胞相互作用的结果。新形成的毛球位于两个不同的部位，一个在截断端，另一个在毛囊的上部区域。在据报道毛囊干细胞所在的隆突区附近没有形成毛球。然而，由于植入物中发生了表皮细胞的迁移和重排，干细胞参与毛球形成的可能性仍然存在。结合对各种真皮区室诱导潜能的比较实验，本研究表明，真皮鞘上层具有诱导毛发的能力，与真皮鞘下层相比，这种能力较弱，但足以诱导毛囊表皮分化成被毛样产毛球，并且仅在这种特定条件下才会被激活。
