Elevated epidermal-specific c-Jun transcription factor by topical ROL in aged human skin in vivo. OCT-embedded skin sections (7μm) were obtained from aged (76±6 years) healthy sun-protected buttock skin after topical treatment of vehicle and 0.4% retinol for seven days. (A) c-Jun immunostaining. Representative images of twelve individuals (N=12). Bars=100μm. (B) c-Fos immunostaining. Representative images of twelve individuals (N=12). Bars=100μm. All immunostainings were quantified by computerized image analysis (Image-pro Plus software, version 4.1, Media Cybernetics, MD) and data are expressed as mean±SEM, *p<0.05. N=12. (C) c-Jun protein. (D) c-Fos protein. Protein levels were determined by Western analysis. Protein levels were normalized to β-actin (loading control). Insets show representative Western blots. Mean ± SEM, N=6, *p < 0.05.