p53 induction in normal human skin in vitro following exposure to solar simulated UV and UV-B irradiation.
Exposure of normal human breast skin ex vivo to physiological levels of UV-B and solar simulated UV results in a UV dose- and time-dependent increase in epidermal p53, as determined by PAGE analysis. Peak p53 levels are detected 12 to 24 h post irradiation with UV-B (470-1410 mJ cm-2) and solar simulated UV (5-12 minimal erythema dose (MED) equivalents). Irradiation with an FS20 UV-B lamp, contaminated with UV-A and UV-C (74-1111 mJ cm-2), also induces peak levels after 12 h incubation at 37 degrees C but these levels persist to 36 h post UV irradiation. In all cases p53 levels start to return to normal by 48 h culture. A significant positive correlation is demonstrated between UV-B dose (47-1645 mJ cm-2) and p53 level (p < 0.01, R > 0.977) in explants cultured for 24 h at 37 degrees C post irradiation. The FS20 induces a 'UV-B' dose-dependent increase in p53 to a maximum from 370 to 1111 mJ cm-2. Similarly, solar simulated UV induces a plateau of peak p53 induction between 5 and 15 MED equivalents. Immunohistochemical analysis using microwave retrieval on 5 microns sections shows the same pattern of p53 staining with UV-B and solar UV insult, but proves unreliable as a method of quantification. These results suggest that the skin explant model may be a useful tool in the evaluation of UV-induced epidermal cell damage, providing a valuable alternative to in vivo studies.
Department of Medicine, Imperial College School of Medicine, Hammersmith Hospital, London, UK.
V
V
Davenport
J F
JF
Morris
R
R
Motazed
A C
AC
Chu
D002452:Cell Count; D002470:Cell Survival; D003720:Densitometry; D004307:Dose-Response Relationship, Radiation; D004591:Electrophoresis, Polyacrylamide Gel; D000078404:Epidermal Cells; D005260:Female; D006801:Humans; D007150:Immunohistochemistry; D012680:Sensitivity and Specificity; D012867:Skin / Q000378:metabolism* / Q000528:radiation effects*; D016159:Tumor Suppressor Protein p53 / Q000096:biosynthesis*; D014466:Ultraviolet Rays
D016159:Tumor Suppressor Protein p53