SKIN EXPOSURE TO CHRONIC BUT NOT ACUTE UV RADIATION AFFECTS PERIPHERAL T-CELL FUNCTION

WEILL, FS; CELA, EM; FERRARI, A; PAZ, ML; LEONI, J; GONZALEZ MAGLIO, DH

JOURNAL OF TOXICOLOGY AND ENVIRONMENTAL HEALTH-PART A-CURRENT ISSUES

TAYLOR & FRANCIS INC

Año: 2011 vol. 74 p. 838 - 847

1528-7394

Ultraviolet (UV) radiation (UVR) produces deleterious effects that may finally lead to carcinogenesis.These adverse effects include tissue inflammation, free radical formation withconsequent oxidation of proteins and lipids, DNA damage, and immune function suppression.The aim of this study was to evaluate the effects of UVR at the local and systemiclevels following acute (4 consecutive days with 0.5 minimal erythema dose [MED]) or chronic(20 consecutive days with 0.25 MED) exposure. Locally, histological alterations and epidermalT-cell populations were studied. Systemically, inguinal lymph-node and spleen T cells wereanalyzed with respect to proliferative response and cytokine production against a nonspecificmitogen. Lymph-node T-cell populations were also characterized. Our results indicated thatwhile both acute and chronic UVR produced epidermal hyperplasia and a decrease in epidermalT-cell density, acute UVR increased T-cell proliferative response, while chronic UVRproduced the opposite effect, shifting the cytokine production toward a Th2/Treg profile.Therefore, even though acute irradiation produced a direct effect on skin, it did not correlatewith a marked modification of overall T-cell response, which is in contrast to marked effectsin chronically irradiated animals. These findings may contribute to understanding the clinicalrelevance of occupational UVR exposure, typically related to outdoor activities, which isassociated with nonmelanoma skin carcinogenesis.