Fig. 6. The histology and immunohistochemistry of hairless (hr/hr) mouse skin. [Reproduced with permission (Panteleyev et al., 1998; Panteleyev et al., 1999a).] (A) The disintegration of HFs in hairless mouse skin results in physical separation of the follicular papilla (FP; alkaline-phosphatase-positive structures – arrows) and upper HF portions including utriculi (u), sebaceous glands (sg) and bulge cells. (B) The bulge-derived downward outgrowth in hairless mouse skin that recapitulates the outer root sheath (ORS) of the normal mouse HF. Bg, the bulge; bo, bulge outgrowth; apm, arrector pili muscle; dc, dermal cyst. (C) Immunohistochemistry (immunofluorescence) with mouse Ki-67-specific antibodies (red) reveals proliferating keratinocytes associated with the detached FP. (D) The cells of bulge-derived outgrowth are also Ki-67 positive (arrowhead), which suggests that they are also proliferating.
