Thalidomide inhibits UVB-induced mouse keratinocyte apoptosis by both TNF-α-dependent and TNF-α-independent pathways

Background: Thalidomide is an anti-inflammatory pharmacologic agent that has been utilized as a therapy for a number of dermatologic diseases. Its anti-inflammatory properties have been attributed to its ability to antagonize tumor necrosis factor-alfa (TNF-α) production by monocytes. However, its mechanism of action in the skin is not known....

The mechanism of N-acetylcysteine photoprotection is not related to dipyrimidine photoproducts

Topical application of N-acetylcysteine prior to UVB irradiation of BALB/c mice has previously been shown to inhibit systemic suppression of the contact hypersensitivity response. Formation of cis-urocanic acid, however, is not affected. Besides urocanic acid, UV-induced DNA damage has been held responsible for the initiation of suppression of...

Induction of interleukin-6 production by ultraviolet radiation in normal human epidermal keratinocytes and in a human keratinocyte cell line is mediated by DNA damage

The sunburn reaction is the most common consequence of human exposure to ultraviolet radiation (UVR), and is mediated at least in part by interleukin- 6 (IL-6). The aim of this study was to determine if DNA is a major chromophore involved in the induction of IL-6 following UV irradiation of a human epidermoid carcinoma cell line (KB), and of...

Cellular target of UVB-induced DNA damage resulting in local suppression of contact hypersensitivity

Experimental data are reviewed that lend support to the hypothesis that formation of DNA damage is the initiation event of local suppression of contact hypersensitivity (CHS) after exposure to ultraviolet (UV) radiaton and that the antigen-presenting cell (APC) is an important traget for this DNA damage. Chemicals/CAS: DNA, 9007-49-2

Immunochemical detection of cyclobutane thymine dimers in epidermal Langerhans cells of UV-B irradiated hairless mice

An immunocytochemical method was developed to study in vivo induction and removal of DNA damage in a specific cell population in the epidermis of hairless mice after ultraviolet B (UVB) exposure: the immunocompetent antigen-presenting Langerhans cells. To this aim, Ia+ cells, which are representative for epidermal Langerhans cells, were compared...

Detection of thymine dimers in suprabasal and basal cells of chronically UV-B exposed hairless mice

An immunocytochemical method was developed to study induction and removal of DNA damage in specific cell populations in the epidermis of hairless mice during chronic ultraviolet (UV) exposure. Identification of mouse suprabasal cells was performed with an immunoperoxidase stain. This stain was shown not to affect the fluorescent nuclear stains,...