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THE EFFECT OF CHRONIC LOW‐DOSE UVB RADIATION ON LANGERHANS CELLS, SUNBURN CELLS, UROCANIC ACID ISOMERS, CONTACT HYPERSENSITIVITY and SERUM IMMUNOGLOBULINS IN MICE
Author(s) -
ElGhorr Ali A.,
Norval Mary,
Lappin Michael B.,
Crosby John C.
Publication year - 1995
Publication title -
photochemistry and photobiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.818
H-Index - 131
eISSN - 1751-1097
pISSN - 0031-8655
DOI - 10.1111/j.1751-1097.1995.tb05276.x
Subject(s) - urocanic acid , sunburn , irradiation , epidermis (zoology) , chemistry , immunology , antibody , immunoglobulin e , langerhans cell , microbiology and biotechnology , medicine , antigen , biology , dermatology , biochemistry , enzyme , physics , nuclear physics , anatomy , histidine
Abstract— C3H mice were irradiated three times a week for up to 6 weeks with either 500 J/m 2 or 1000 J/m 2 broadband UVB (270–350 nm) or 3000 J/m 2 narrowband UVB (311–312 nm; TL01 source). Each dose was suberythemal to the mouse strain used. The number of Langerhans cells (LC) in the epidermis was reduced by over 50% after 2 weeks of irradiation with the UVB source and by 20% following TL01 irradiation. Continued irradiation for up to 6 weeks resulted in no further decrease in LC numbers in the case of the UVB source but a steady decline to 40% in the case of the TL01 source. Sunburn cells were detected following irradiation with both sources but the numbers were very low in comparison with acute exposure. Ultraviolet‐B exposure resulted in doubling of the thickness of the epidermis throughout the 6 weeks of irradiation while TL01 exposure did not alter epidermal thickness. Conversion of trans‐ to ew‐urocanic acid (UCA) was observed with both UVB and TL01 sources. The percentage of cis ‐UCA started to return to normal after 4 weeks of TL01 exposure despite continued irradiation. As observed following a single exposure, the contact hypersensitivity (CH) response was significantly reduced following 6 weeks of UVB irradiation but was unaffected by TL01 exposure, indicating no correlation between cis ‐UCA levels and CH response. Total serum immunoglobulin levels remained unchanged throughout the 6 weeks of UVB or TL01 irradiation but IgE titers significantly increased in all cases in the first 2 weeks of irradiation, indicating a possible shift to a T H2 cytokine profile. The IgE levels started to return to normal at later times. Thus chronic broadband UVB exposure induces a number of cutaneous and systemic responses that are likely to be dose dependent, while chronic TL0I exposure induces only some of the these responses.