High-intensity swimming exercise increases dust mite extract and 1-chloro-2,4-dinitrobenzene-derived atopic dermatitis in BALB/c mice

The aim of this study was to investigate the effect of high-intensity swimming exercise (HISE) on atopic dermatitis (AD). For the study, we established an AD model in BALB/c mice by repeated local exposure of house dust mite extract (Dermatophagoides farinae extract, DFE) and 1-chloro-2,4- dinitrobenzene (CDNB) to the ears. After HISE for 4 weeks, epidermal thickness, mast cell infiltration, serum immunoglobulin E (IgE), and histamine were measured. In addition, the gene expression of interleukin (IL)-5 and IL-31 in the ears was assayed. HISE increased DFE/CDNB-induced AD symptoms based on ear thickness, histopathological analysis, and serum IgE level. Moreover, HISE exercise stimulated mast cell infiltration into the ear, elevation of serum histamine, and DFE/CDNB-induced expression of IL-5 and IL-31 in the ears in the AD model. Taken together, our results indicate the possibility that HISE-induced stress gives rise to AD symptoms through the stimulation of IgE level by increasing IL-5 and IL-31 production.