A, B) UVR-induced changes in lipid metabolizing enzyme expression in the epidermis following 10-wk supplementation with EPA (A) or DHA (B). Expression of COX-2, 12-LOX, 15-LOX, and NAPE-PLD in unirradiated epidermis and epidermis at 24 and 72 h after UVR exposure (3× MED), both before and after supplementation with EPA or DHA. Expression was assessed by immunohistochemistry, and data are shown as the percentage of epidermis staining positive for enzyme expression (means ± sd; EPA: n = 12 and DHA: n = 9 volunteers). *P < 0.05; **P < 0.001; ****P < 0.0001 presupplementation vs. 0 h presupplementation. #P < 0.05; ##P < 0.01; ####P < 0.0001 postsupplementation vs. 0 h postsupplementation. C) Representative photomicrographs of NAPE-PLD expression (red staining in the epidermis) in unirradiated skin and skin 24 and 72 h after UVR exposure (3× MED), both presupplementation and postsupplementation with DHA. Scale bar, 100 µm.