A three-dimensional observation of human hair tissue treated by modified trypsin-HC1 method

Abstract

To observe the three-dimensional ultrastructures of human hair and hair follicle under scanning electron microscope, biopsied scalp tissues were treated by the combination of the trypsin-HC1 method and ultrasonic cleaning. After this treatment, the connective tissues surrounding the hair follicle were removed to permit the three dimensional observation of hair tissue. The following findings were obtained; 1) The basal plate, composed of fibroblasts and collagen fibers, was seen as a small disc covering the entrance of hair papilla, 2) The connective tissue (fibrous) sheet, with a capillary network, tightly surrounded the lower hair follicle. 3) A morphological difference in the cells between the cell layers constituting the hair bulb was seen; there were discoid cells in the outer and spherical cells in inner layer, 4) Numerous micro-villous projections were present on the surface of outer root sheath cells and on the surface of keratinized inner root sheath; the latter surface resembled the bark of a tree in appearance. The present modified method seems useful for three-dimensional ultrastructural observation of human hair and hair follicles.