Mori O, Uno H
Department of Dermatology, Kurume University School of Medicine, Japan.
J Dermatol. 1990 May;17(5):276-81. doi: 10.1111/j.1346-8138.1990.tb01641.x.
To explore an easily accessible and reproducible model for examining the effect of minoxidil on hair growth, we studied the effect of minoxidil on the natural hair cycles of rats from birth to 80 days of age. During the 1st and 2nd postnatal cycles, the hair follicles grew very rapidly and the size of anagen follicles were markedly enlarged. In the 3rd cycle (50 days to approximately 100 days of age), duration of the telogen phase lasted approximately 20 days. Topical minoxidil, 1%, 3%, or 5% solution, applied on the backs of the rats from 23 days (weaning) to 80 days, induced a remarkable shortening of the telogen phase in the 3rd cycle. Although the dose-dependent response was very minimal, rats treated with 3% or 5% minoxidil showed similar effects in the 4th cycle. Minoxidil, however, did not induce prolongation of the anagen phase, but increased the rate of DNA synthesis in the anagen bulb during the 2nd and 3rd cycles. These results suggest that minoxidil specifically stimulates the secondary germ of the telogen follicles, resulting in rapid progression to anagen follicles.
为探索一种便于获取且可重复的模型来研究米诺地尔对毛发生长的影响，我们研究了米诺地尔对出生至80日龄大鼠自然毛发周期的影响。在出生后的第1和第2个周期，毛囊生长非常迅速，生长期毛囊大小明显增大。在第3个周期（50天至约100日龄），休止期持续约20天。从23天（断奶）至80天，将1%、3%或5%的米诺地尔溶液局部涂抹于大鼠背部，可使第3个周期的休止期显著缩短。尽管剂量依赖性反应非常微小，但在第4个周期，用3%或5%米诺地尔处理的大鼠表现出相似的效果。然而，米诺地尔并未诱导生长期延长，但在第2和第3个周期增加了生长期毛球中的DNA合成速率。这些结果表明，米诺地尔特异性刺激休止期毛囊的次级毛胚，导致其迅速进入生长期毛囊。
