(a) Preparation of skin extract and HF neogenesis assay. (b, b′) Effect of skin extract on HF induction. Regenerated HFs
are pigmented because the P1 keratinocyte preparation also contains melanocyte progenitors. #p < 0.05 with
Fisher’s test, compared with P1 KCs only (n = 10). (c) E16.5 skin extract induced new HFs with new DPs (red
arrowhead). (d) New HFs formed from lacZ+ keratinocytes exhibited β-galactosidase activity in the epithelium,
including the sebaceous gland (yellow arrowhead), but not in the DP (red arrowhead). (e) In full-thickness wounds of nude mice,
incorporation of E16.5 extract into dermal equivalents induced HF neogenesis from transplanted C57BL/6 mouse keratinocytes.
#p < 0.05 with Fisher’s test, compared with nascent E16.5 skin extract (n = 10). All insets show
enlarged images of the regenerated HFs. KC: keratinocyte. Bar: histology, 100 μm; gross images, 500 μm. (For
interpretation of the references to colour in this figure legend, the reader is referred to the web version of this article.)