Fig. 2: Myoepithelial cells in eccrine glands visualized by actin staining.

a Schematic illustration of an eccrine gland. b The coiled structure of a human eccrine gland visualized by Acti-stain. High-magnification images of the excretory duct (ED; c) and the secretory duct (SD; d) in b. Acti-stain distinctly delineated the cuboidal cells of the excretory duct (c) and spindle-shaped cells in the secretory duct (d). e The coiled portion of the eccrine gland was characterized by αSMA immunoreactivity (magenta), Acti-stain (green) and Hoechst 33342 staining (blue). High-magnification images of the secretory (f) and excretory (g) ducts in e. αSMA was abundant in the spindle-shaped myoepithelial cells of the secretory duct (f, red dashed lines) but absent from the excretory duct (g, the excretory duct is outlined with white dotted lines). h Acti-stain (middle) and Hoechst 33342 staining (right) distinctly labeled the secretory and excretory ducts with respect to the cell shape and density of nuclei. Arrows indicate the excretory duct, and arrowheads indicate the actin-rich secretory duct. i High-magnification images of the transition region between the SD and ED (boxed in h). The red dotted line indicates the border. The arrowheads indicate the elliptical nuclei of myoepithelial cells of the secretory duct, and the arrows indicate the round nuclei of the luminal cells of the excretory duct.