Buhl A E, Waldon D J, Kawabe T T, Holland J M
Hair Growth Research, Upjohn Company, Kalamazoo, Michigan 49001.
J Invest Dermatol. 1989 Mar;92(3):315-20. doi: 10.1111/1523-1747.ep12277095.
Minoxidil, a potent vasodilator, stimulates the growth of terminal hair from vellus or miniaturized follicles in balding scalp. To study minoxidil's action on isolated follicles we developed and validated an organ culture system using mouse whisker follicles. Control follicles cultured without minoxidil showed macroscopic changes including kinking of the hair shafts and bending of the follicles. Necrosis was evident in the differentiating epithelial elements forming the cuticle, cortex, and inner root sheath. These abnormalities were eliminated or greatly reduced in minoxidil-treated follicles. The morphology of these follicles was consistent with the production of new hair during culture. Direct measurement demonstrated that minoxidil-treated follicles grew significantly longer than control follicles during the 3-d culture. Minoxidil increased the incorporation of radiolabeled cysteine and glycine in follicles compared with control treatment. Doses of minoxidil up to 1 mM caused increased cysteine incorporation, while higher doses were inhibitory. Experiments with labeled thymidine indicated that minoxidil induced proliferation of hair epithelial cells near the base of the follicle. Autoradiography also showed that cysteine accumulated in the keratogenous zone above the dermal papilla. These studies demonstrate that organ cultured follicles are suitable for determining minoxidil's mechanism of action and may be useful for studying other aspects of hair biology. The results also show that minoxidil's effect on hair follicles is direct. This suggests that minoxidil's action in vivo includes more than just increasing blood flow to hair follicles.
米诺地尔是一种强效血管扩张剂，可刺激秃发头皮上毳毛或小型化毛囊生长终毛。为了研究米诺地尔对分离毛囊的作用，我们开发并验证了一种使用小鼠触须毛囊的器官培养系统。未用米诺地尔培养的对照毛囊出现了宏观变化，包括毛干扭结和毛囊弯曲。在形成角质层、皮质和内根鞘的分化上皮成分中可见坏死。在米诺地尔处理的毛囊中，这些异常现象消失或大大减少。这些毛囊的形态与培养过程中新毛发生成一致。直接测量表明，在3天的培养过程中，米诺地尔处理的毛囊比对照毛囊长得明显更长。与对照处理相比，米诺地尔增加了毛囊中放射性标记的半胱氨酸和甘氨酸的掺入。高达1 mM的米诺地尔剂量导致半胱氨酸掺入增加，而更高剂量则具有抑制作用。用标记胸苷进行的实验表明，米诺地尔诱导毛囊基部附近的毛上皮细胞增殖。放射自显影还显示，半胱氨酸在真皮乳头上方的角质形成区积累。这些研究表明，器官培养的毛囊适用于确定米诺地尔的作用机制，可能有助于研究毛发生物学的其他方面。结果还表明，米诺地尔对毛囊的作用是直接的。这表明米诺地尔在体内的作用不仅仅是增加毛囊的血流量。
