Sugie N, Fujii N, Danno K. Cyclosporin-A suppresses p53-dependent repair DNA synthesis and apoptosis following ultraviolet-B irradiation.
PHOTODERMATOLOGY, PHOTOIMMUNOLOGY & PHOTOMEDICINE 2002;
18:163-8. [PMID:
12390669 DOI:
10.1034/j.1600-0781.2002.00765.x]
[Citation(s) in RCA: 26] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
Abstract
BACKGROUND
The combination of cyclosporin-A (CS-A) and ultraviolet-B (UV-B) irradiation is not recommended in the treatment of psoriasis, because risks of UV-B-induced skin cancer are increased. The recommendation, however, has not well been confirmed by basic researches.
PURPOSE
In this study, we investigated the effects of CS-A on UV-B-induced repair DNA synthesis, apoptosis and p53 expression.
METHODS
Following the short-term administration of CS-A (5 and 50 mg/kg/day) or vehicle (V) alone, female BALB/c mice, 8-10 weeks old, were treated with UV-B irradiation (100 and 500 mJ(2) cm) or tape stripping (TS). After the treatment, the effects of CS-A on the increased rate of epidermal DNA synthesis were examined by using 5'-bromodeoxyuridine (BrdU) pulse-labelling techniques. In separate experiments, the effects of CS-A on the number of sunburn cells, nick-end labelling+ cells and p53+ cells were examined 24 h after UV-B irradiation.
RESULTS
Cyclosporin-A significantly suppressed the UV-B-induced increase in BrdU uptake, which occurs to repair DNA damage, while there were no significant effects on the stripping (S)-induced increase or the rate of normal epidermal proliferation, which is not associated with any DNA injuries. The number of sunburn cells, nick-end labelling+ cells and p53+ cells was significantly reduced by pretreatment with CS-A.
CONCLUSION
Cyclosporin-A interferes with the self- protective mechanisms involved in both repair and apoptotic removal of UV-B-induced DNA damage. The loss of p53 expression is responsible for the effects of CS-A.
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