“Skin ultraviolet B irradiation: response to an acute dose and effect of the topical application of cyclooxigenase inhibitor”

GONZALEZ MAGLIO DANIEL; PAZ MARIELA LAURA; FERRARI ALEJANDRO; WEILL FEDERICO; NIETO JORGE; LEONI JULIANA

Córdoba, Argentina.

Congreso; VII Latin American Congress of Immunology; 2005

Asociación Latinoamericana de Inmunología

Objectives Analyze the effects of an acute ultraviolet B (UVB) dose on the expression of inducible Nitric Oxide Synthase (iNOS) and Cyclooxigenases (COX), the synthesis of Prostaglandin E2 (PGE2) and the skin histology. Evaluate the effect of the topical application of a COX inhibitor after irradiation. Methods Hairless mice were irradiated with 200 mJ/cm2 of UVB light. iNOS and COX expression was evaluated in epidermis homogenates by Western Blot and PGE2 synthesis by ELISA. COX inhibition was performed with an aqueous solution of Naproxen. Results iNOS expression increased in a time-dependent manner, reaching 33 times the control levels. COX-1 showed no changes, while COX-2 is slightly increased (7.6 times) as well as PGE2 synthesis (2.8 times). Histological analysis showed a marked disruption between skin layers and an increase in the sun burn cells number; a slight improvement is observed 72 hours after treatment. Topical application of Naproxen severely decreased the levels of PGE2 synthesis; it also decreased the iNOS expression and improved the histological features. Conclusion UVB irradiation causes an increase in inflammatory mediators and alterations in skin histology. Topical application of Naproxen can reduce the levels of inflammatory mediators leading to a reduction in skin sun burn.