Role of solar conditioning in DNA repair response and survival of human epidermal keratinocytes following UV irradiation
The authors have investigated the cumulative effects of sunlight exposure upon the excision-repair of UV radiation damage to DNA in epidermal keratinocytes from human donors of different ages as well as the possible effect on DNA repair of periodic conditioning of the cultured keratinocytes with sublethal UV radiation exposures. The authors have also compared the growth properties of UV-irradiated keratinocytes derived from habitually sun-exposed and nonexposed areas from the bodies of young and aged donors. DNA repair replication in keratinocytes from habitually sun-exposed facial skin and the less sun-exposed abdominal skin of middle-aged adults was found to be similar, with respect to both the UV dose response and the time course of repair after 20 J/m2, 254 nm. Growth and survival (after exposure up to 50 J/m2, 254 nm) were greater for keratinocytes from protected areas of the upper arm of young donors (under 18 years) than for cells from their own sun-exposed areas. Growth and survival were markedly reduced for all keratinocyte cultures from aged donors, especially those cultures developed from sun-exposed areas. Nevertheless, the DNA repair response to UV radiation was similar in all cases. The evident uncoupling of UV sensitivity from DNA repair capacity remains to be understood. These studies confirm that the cumulative effect of sunlight exposure indeed contributes to some skin aging processes. However, the authors have found no indication that an overall reduction in capacity for excision-repair of UV photoproducts in keratinocyte DNA accompanies senescence in human skin.
- Research Organization:
- Stanford Univ. School of Medicine, CA
- OSTI ID:
- 5124841
- Journal Information:
- J. Invest. Dermatol.; (United States), Vol. 2
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
EPIDERMIS
BIOLOGICAL RADIATION EFFECTS
DNA REPAIR
ABDOMEN
AGE DEPENDENCE
AGING
CELL CULTURES
COMPARATIVE EVALUATIONS
DNA REPLICATION
DOSE-RESPONSE RELATIONSHIPS
FACE
KERATIN
SKIN
SURVIVAL TIME
ULTRAVIOLET RADIATION
ANIMAL TISSUES
BIOLOGICAL EFFECTS
BIOLOGICAL RECOVERY
BIOLOGICAL REPAIR
BODY
BODY AREAS
ELECTROMAGNETIC RADIATION
EPITHELIUM
HEAD
NUCLEIC ACID REPLICATION
ORGANIC COMPOUNDS
ORGANS
PROTEINS
RADIATION EFFECTS
RADIATIONS
RECOVERY
REPAIR
SCLEROPROTEINS
TISSUES
560121* - Radiation Effects on Cells- External Source- (-1987)