Fig. 3. Histological observation on SKH-1 hairless mice skin applied with test compounds for 4 wks. (A) H&E stain, ×200, (B) Masson’s trichrome stain, ×200, (C) Verhoeff’s stain, ×200, (D) Toluidine blue stain, ×200 magnification. N: saline-treated normal group, C: UVBirradiated control group, RA 0.01%: 0.01% retinoic acid-treated group, GT 2%: 2% green tea-treated group, WT 2%: 2% white teatreated group, BT 2%: 2% black tea-treated group. Scale bar 100 μm. The epidermis and dermis of control group were remarkably thickened in comparison with normal group. A moderate large numbers of neutrophil and lymphocyte were infiltrated in the dermis of control group (A), and collagen fibers (B) and elastic fibers (C) in the dermis were arranged irregularly in control groups. A large number of mast cells were found in the dermis and hypodermis of control group and their degranulation was severe, whereas a few numbers of mast cells were observed in the dermis of RA and CSWE groups (D).