Melatonin Regulates Arylhydrocarbon Receptor Mediated UVR‐Induced Processes Related to Inflammation, Skin Aging and Carcinogenesis in Human Ex Vivo Skin

M) at both time points. Further, melatonin significantly reduced gene expression of AhR by 21.2% (p < 0.01), p27 by 24.8% (p < 0.01), COX-2 by 42.9% (p < 0.001), MAPK14 by 6.6% (p < 0.05) and MMP2 by 8.2% (p < 0.05), and caused a 10.2% (n.s.) TIMP1 reduction tendency 24 h post-irradiation. Thus, melatonin prevented UV-dependent expression of AhR and downstream regulators of AhR-mediated processes possibly related to inflammation, cellular aging and carcinogenesis on protein and gene level in UV-irradiated skin.