Figure 2.
Galectin-7 expression is increased in sunburn keratinocytes formed in normal human skin ex vivo after UVB exposure. Normal human skin on grids was sham-irradiated (A, C, and E) or exposed to UVB 750 J/m2 (B, D, and F). Twenty-four hours after irradiation, samples were processed for histology (A and B), TUNEL reaction (C and D), and galectin-7 immunostaining (E and F). Histological examination reveals that UVB irradiation induces the formation of numerous sunburn cells within the suprabasal compartment of the epidermis (B, arrows). In sham-irradiated skin, rare positive nuclei restricted to the terminally differentiated keratinocytes are detected by the TUNEL reaction (C, arrowheads). In UVB-irradiated samples, numerous apoptotic/TUNEL-positive keratinocytes are detected within the suprabasal epidermal compartment (D, arrows). In sham-irradiated samples, immunolabeling using the anti-galectin-7 antibody reveals that all living epidermal cell layers express galectin-7 (E). In UVB-irradiated samples, galectin-7 labeling also is observed throughout the epidermal compartment. In addition, UVB irradiation induces a much higher level of galectin-7 expression in some suprabasal keratinocytes (F, arrows). Gal-7 indicates sections labeled by using the anti-galectin-7 antiserum; TUNEL indicates sections processed for the TUNEL labeling. Dotted lines indicate the dermal-epidermal junction. (Bar: 25 μm.)