Ozonated oil alleviates dinitrochlorobenzene-induced allergic contact dermatitis via inhibiting the FcεRI/Syk signaling pathway.

OBJECTIVES: Ozone is widely applied to treat allergic skin diseases such as eczema, atopic dermatitis, and contact dermatitis. However, the specific mechanism remains unclear. This study aims to investigate the effects of ozonated oil on treating 2,4-dinitrochlorobenzene (DNCB)-induced allergic contact dermatitis (ACD) and the underling mechanisms. METHODS: Besides the blank control (Ctrl) group, all other mice were treated with DNCB to establish an ACD-like mouse model and were randomized into following groups: a model group, a basal oil group, an ozonated oil group, a FcεRI-overexpressed plasmid (FcεRI-OE) group, and a FcεRI empty plasmid (FcεRI-NC) group. The basal oil group and the ozonated oil group were treated with basal oil and ozonated oil, respectively. The FcεRI-OE group and the FcεRI-NC group were intradermally injected 25 µg FcεRI overexpression plasmid and 25 µg FcεRI empty plasmid when treating with ozonated oil, respectively. We recorded skin lesions daily and used reflectance confocal microscope (RCM) to evaluate thickness and inflammatory changes of skin lesions. Hematoxylin-eosin (HE) staining, real-time PCR, RNA-sequencing (RNA-seq), and immunohistochemistry were performed to detct and analyze the skin lesions. RESULTS: Ozonated oil significantly alleviated DNCB-induced ACD-like dermatitis and reduced the expressions of IFN-γ, IL-17A, IL-1β, TNF-α, and other related inflammatory factors (all P<0.05). RNA-seq analysis revealed that ozonated oil significantly inhibited the activation of the DNCB-induced FcεRI/Syk signaling pathway, confirmed by real-time PCR and immunohistochemistry (all P<0.05). Compared with the ozonated oil group and the FcεRI-NC group, the mRNA expression levels of IFN-γ, IL-17A, IL-1β, IL-6, TNF-α, and other inflammatory genes in the FcεRI-OE group were significantly increased (all P<0.05), and the mRNA and protein expression levels of FcεRI and Syk were significantly elevated in the FcεRI-OE group as well (all P<0.05). CONCLUSIONS: Ozonated oil significantly improves ACD-like dermatitis and alleviated DNCB-induced ACD-like dermatitis via inhibiting the FcεRI/Syk signaling pathway.