Takizawa T, Takizawa T, Arai S, Osumi M, Saito T
Department of Anatomy, Jichi Medical School, Tochigi, Japan.
Anat Rec. 1998 Jul;251(3):406-13. doi: 10.1002/(SICI)1097-0185(199807)251:3<406::AID-AR17>3.0.CO;2-S.
Human scalp hair is important as a diagnostic clue to many diseases, in medical jurisprudential investigations, and also as a subject of cosmetic treatments. While many ultrastructural studies of the human hair root including the hair follicle have been reported, few studies have been done on the human hair shaft. We report here the ultrastructure of human scalp hair shafts prepared by a rapid-freezing technique followed by freeze-substitution fixation that allows the observation of fine cell structures. Healthy scalp hair shafts from Japanese females 12-13 years of age were rapid-frozen and then freeze-substituted in OsO4-acetone. In addition, this technique was applied to the study of some changes of the hair shafts (i.e., hair damaged by thioglycolic acid cold permanent waving and white hair). By this method, the hair shaft was rapid-frozen throughout without appreciable ice damage although the hair shaft was nearly 100 microm in diameter. The rapid-freezing technique resulted in excellent preservation of the ultrastructure of the hair shafts: lamellar structures in the cuticle and fine fibrous ultrastructures in the cortex were observed without chemical treatments. Thioglycolic acid treatment affected the ultrastructure of both the cuticle and the cortex. Except for the absence of melanin granules, no significant differences in the ultrastructure were observed between white hair and black hair. The rapid-freezing technique followed by freeze-substitution fixation appears to be the most reliable approach for the morphological evaluation of fully keratinized cells and tissues.
人类头皮毛发在许多疾病的诊断线索、法医学调查以及美容治疗方面都很重要。虽然已经有许多关于包括毛囊在内的人类发根超微结构的研究报道，但对人类毛干的研究却很少。我们在此报告采用快速冷冻技术并随后进行冷冻置换固定所制备的人类头皮毛干的超微结构，这种方法能够观察到精细的细胞结构。对12 - 13岁日本女性的健康头皮毛干进行快速冷冻，然后在四氧化锇 - 丙酮中进行冷冻置换。此外，该技术还应用于研究毛干的一些变化（即巯基乙酸冷烫损伤的毛发和白发）。通过这种方法，尽管毛干直径近100微米，但整个毛干都能快速冷冻且没有明显的冰损伤。快速冷冻技术使毛干的超微结构得到了很好的保存：在未经化学处理的情况下，观察到了角质层的层状结构和皮质的精细纤维超微结构。巯基乙酸处理影响了角质层和皮质的超微结构。除了没有黑色素颗粒外，白发和黑发在超微结构上没有观察到显著差异。快速冷冻技术随后进行冷冻置换固定似乎是对完全角化的细胞和组织进行形态学评估的最可靠方法。
