Surface treatment with non-thermal humid argon plasma as a treatment for allergic contact dermatitis in a mouse model

Purpose

Cold plasma generated at atmospheric pressure has attracted intense interest in biomedical applications. However, studies of cold plasma in dermatology, and as a possible therapy for non-infectious skin diseases, including burn and wound healing, psoriasis, and allergic contact dermatitis (ACD) etc., are still quite scarce. The present study reports the treatment of ACD in vivo, using a non-thermal humid plasma source in a mouse model and shows the latter could be a potential alternative approach for therapy of ACD and other inflammatory skin diseases.

Methods

The model of ACD on the mouse back was induced by a solution of DNFB and treated by argon plasma containing small amounts of either N₂, O₂, or H₂O. The developments of ACD regions were photographed and histopathological analysis by H&E-staining was performed.

Results

The best effect was obtained using humid plasma (H₂O addition), where the ACD symptoms decreased after one or two 1-min plasma treatments. Even for severe ACD with ulcers and crust formation, the humid plasma-treated mice recovered faster than the control group.

Conclusions

The therapeutic ability of the humid argon plasma discharge was proposed to be induced by reactive oxygen species (H_xO_y) transported from the discharge zone, which are adhesive and accumulate on the skin surface, penetrating the subcutis to eliminate inflammation. However, in treatments using plasma with addition of oxygen or nitrogen (without water) the active gaseous species are blocked due to poor adhesion to and penetration into the dry ACD skin, with correspondingly poor treatment effects. The enhanced in vivo healing in ACD mice indicate the non-thermal humid plasma could be a potential alternative approach for therapy of ACD and other inflammatory skin diseases.