Modest in vivo exposure to solar wavelengths induces a visible absorbing chromophore in Skh-1 mouse epidermis.

Autor: Menter JM; Division of Dermatology, Department of Medicine, Morehouse School of Medicine, Atlanta, GA 30310-1700, USA. menterj@msm.edu, Sayre RM, Dowdy JC, Etemadi AA, Patta AM, Chappell J, Willis I
Jazyk: angličtina
Zdroj: Photodermatology, photoimmunology & photomedicine [Photodermatol Photoimmunol Photomed] 2004 Oct; Vol. 20 (5), pp. 252-6.
DOI: 10.1111/j.1600-0781.2004.00107.x
Abstrakt: Background/purpose: In the previous work, we correlated epidermal hyperplasia with increased epidermal absorption in the 250-400 nm region. During a recent review of that work, the apparent formation of a chromophore, with absorption slightly longer than 400 nm, in the epidermis of irradiated animals was noted. In this study, we have extended the transmission measurement to include the 250-800 nm region.
Methods: Age-matched Skh-1 hairless mice were separated into three groups. One group was irradiated with 6.3 J/cm(2) (0.9 minimal erythemal dose; MED) of solar simulating ultraviolet radiation (SSUVR) five times/week for 2 weeks, then increased to 1.1 MED (7.1 J/cm(2)) for two additional weeks (20-day group). A second 10-day group, added halfway through the protocol, was irradiated with 0.9 MED five times/week for 2 weeks. The control group received no UV irradiation. Routine H&E staining and epidermal absorption spectral analysis were carried out on biopsy specimens from each animal.
Results: This work confirms the development or enhancement of a visible chromophore with a maximum absorption at ca 412 nm. This peak appears to be radiation dose dependent. It can be discerned in both the groups, albeit more prominently in the 20-day animals. The absorption is sufficiently strong to impart a yellow to reddish appearance to skin viewed in full spectrum visible light.
Conclusions: Accumulation of such a chromophore in humans may contribute to the coloration of chronically exposed skin. The absorption strength and wavelength location of the peak is strongly suggestive of a heme-like compound. We are currently conducting experiments to further characterize this chromophore.
Databáze: MEDLINE
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