Figure 8.

Effects of EEB on skin thickening, collagen degradation, and skin hydration in the dorsal skin of UVB-irradiated HR-1 hairless mice. HR-1 hairless mice were orally administrated with various doses of EEB (50, 100, and 200 mg/kg, p.o.) every 6 days and irradiated with UVB three times per week for 8 weeks (60 mJ/cm² to 120 mJ/cm²). (A) Dorsal skin thickness was measured using a caliper. (B) Histogram of epidermal thickness measured using the (C) H&E-stained images of dorsal skin tissues. Scale bar = 500 µm. (D) Masson’s trichrome-stained images of dorsal skin tissues. Scale bar = 1 mm. Dorsal skin tissue-lysates were analyzed by Western blotting to determine the protein levels. Protein expression of (E) Pro-COL1A1, (F) p-Smad2/Smad3, and total Smad2/Smad3. (G) The epidermal water content and (H) TEWL were measured using the GPSkin Barrier^® in the dorsal skin of UVB-irradiated HR-1 hairless mice. Each symbol in the figures represents an individual mouse of its own group. Protein levels of pro-COL1A1 and Smad pathway normalized to β-actin were determined using Bio-Rad Quantity One software (Basic; Bio-Rad Laboratories Inc., Hercules, CA, USA). Values are represented as mean ± SEM (n = 6). # p < 0.05 vs. the vehicle-treated control group; ** p < 0.01 and *** p < 0.001 vs. the UVB only-treated group.