A and B, JB6 cells were pretreated with quercitrin (10, 20, and 40 μM) or acetone for 1 h prior UVB exposure. After 2 h, the cells were collected to quantify 8-OHdG production using ELISA analysis. C, The animal treatment is the same as that in Fig. 1. At 1 day and 7 days of 6-week treatment, the mice were euthanized and dorsal skin tissues were isolated and fixed in 10% formalin. The mouse skin sections were used to immunohistological staining with 8-OHdG. Arrows show example of 8-OHdG stained in some cells.