IL-18 and IFN-gamma expression enhances contact hypersensitivity after oral administration of naturally oxidized olive oil to mice

The consumption of oxidized cooking oils may exacerbate some allergic diseases. A contact hypersensitivity (CHS) mouse model was used to investigate the effects of naturally oxidized olive oil on the expression of inflammatory cytokines after a sensitization and elicitation phase. The mRNA expressions of IL-12, IL-18, and IFN-gamma in the ear increased seven days after sensitization. IL-18 and IFN-gamma mRNA expressions after elicitation were significantly enhanced by administration of oxidized olive oil, which exacerbated ear swelling and mononuclear cell infiltration from CHS after elicitation. IL-18 expression in the ear of oxidized oil-treated mice was highest before elicitation and decreased with an increase in IFN-gamma expression after elicitation. The acceleration of an immune reaction by administration of naturally oxidized olive oil in the CHS mouse model was caused by increased expression of IL-18 in the ear auricles after sensitization, which was followed by a significant increase in IFN-gamma expression after elicitation.