Characterization of epidermal cytokine profiles in sensitization and elicitation phases of allergic contact dermatitis as well as irritant contact dermatitis in mouse skin.

Abstract

Epidermal cytokines are known to participate in the initiation of immune and inflammatory processes in the skin. In the present study, we examined epidermal cytokine mRNA levels to elucidate the initial molecular events in the sensitization and elicitation phases of allergic contact dermatitis (ACD) as well as in irritant contact dermatitis (ICD). BALB/c mice were sensitized on the dorsal skin with 0.5% dinitrofluorobenzene (DNFB) and challenged with 0.2% DNFB on the ears 6 days later to elicit allergic contact hypersensitivity (ACDe), the elicitation phase. To examine cytokine profiles during the sensitization phase from the same anatomic area, other animals were sensitized on ear instead of dorsal skin. The sensitization phase of ACD (ACDs) was induced by painting the ears of naive mice with 0.5% DNFB. Sodium lauryl sulfate (SLS), utilized as an irritant control, was also applied to the ears of another group of mice to induce ICD. Total RNA was extracted from the epidermis of the treated ears at various time points after each treatment, reverse transcribed to cDNA, and amplified by PCR using radiolabeled cytokine-specific primers. Amplified products were sized by electrophoresis and autoradiography and semiquantitated by densitometry. Autoradiographs were normalized relative to beta-actin signals. ACDs and ACDe showed similar patterns of cytokine mRNA levels; that is, at 6 h after hapten application, interleukin (IL)-1 beta, IL-6, IL-10, and granulocyte-macrophage colony-stimulating factor (GM-CSF) mRNA levels were upregulated, and this upregulation was observed until 24 h after treatment.(ABSTRACT TRUNCATED AT 250 WORDS)