Photoprotective role of epidermal melanin granules against ultraviolet damage and DNA repair in guinea pig skin

Journal Article · Thu Nov 01 04:00:00 EST 1984 · Cancer Res.; (United States)

OSTI ID:5970442

Ishikawa, T; Kodama, K; Matsumoto, J; Takayama, S

We previously developed a quantitative autoradiographic technique with special forceps for measuring unscheduled DNA synthesis (UDS) in mouse skin after treatment with ultraviolet light in vivo. By this method, we investigated the relationship between the protective role of melanin and UV-induced DNA repair in black-and-white guinea pigs. Flat areas containing a sharp border between pigmented and unpigmented skin were selected. The skin of the selected areas was shaved and irradiated with short-wave UV (254 nm) or UV-AB (270 to 440 nm, emission peak at 312 nm) at various doses. Immediately after irradiation, the skin was clamped off with forceps, and an isotonic aqueous solution of (methyl-/sup 3/H)thymidine was injected s.c. into the clamped off portion. UDS was clearly demonstrated as silver grains in this portion of the skin after irradiation with 254 nm UV or UV-AB. Errors due to individual differences were avoided by comparing the intensities of UDS in basal cells from pigmented skin and unpigmented skin of the same animals. Unexpectedly, in groups of animals treated with 254 nm UV or UV-AB, no difference in UDS in pigmented and unpigmented skin was seen at any UV dose. These results suggested that epidermal melanin granules do not significantly protect DNA of basal cells against 254 nm UV or UV-AB irradiation. Results of a study on the effect of the wavelength of irradiation on the UDS response of albino guinea pigs are also reported.

• Research Organization: Japanese Foundation for Cancer Research, Tokyo
• OSTI ID: 5970442
• Journal Information: Cancer Res.; (United States), Journal Name: Cancer Res.; (United States) Vol. 44:11; ISSN CNREA
• Country of Publication: United States
• Language: English

Related Subjects

560152* -- Radiation Effects on Animals-- Animals
63 RADIATION, THERMAL, AND OTHER ENVIRON. POLLUTANT EFFECTS ON LIVING ORGS. AND BIOL. MAT.
ANIMALS
BIOLOGICAL EFFECTS
BIOLOGICAL FUNCTIONS
BIOLOGICAL RADIATION EFFECTS
BIOLOGICAL RECOVERY
BIOLOGICAL REPAIR
BODY
DNA REPAIR
DOSES
ELECTROMAGNETIC RADIATION
FUNCTIONS
GUINEA PIGS
HYDROXY COMPOUNDS
MAMMALS
MELANIN
ORGANIC COMPOUNDS
ORGANIC NITROGEN COMPOUNDS
ORGANS
PIGMENTS
RADIATION DOSES
RADIATION EFFECTS
RADIATION PROTECTION
RADIATIONS
RADIOSENSITIVITY EFFECTS
RECOVERY
REPAIR
RODENTS
SKIN
ULTRAVIOLET RADIATION
VERTEBRATES