Lycopus lucidus Turcz ameliorates DNCB­induced atopic dermatitis in BALB/c mice.

ABSTRACT

Atopic dermatitis (AD) is a chronic inflammatory allergic skin disease, characterized by pruritic and eczematous skin lesions. Lycopus lucidus Turcz (LLT) is a perennial herb that has been reported to have various biological properties, including effects on blood circulation, as well as anti­inflammatory, antioxidant, anti­vascular inflammation and wound­healing effects. However, whether LLT improves dermatitis and the underlying mechanisms has yet to be determined. The aim of the present study was to determine whether LLT can improve 2,4­dinitrochlorobenzene (DNCB)­induced dermatitis and to verify the inhibitory effect of LLT on the expression of chemokines and pro­inflammatory cytokines in the HaCaT immortalized keratinocyte cell line. In addition, the anti­inflammatory function of LLT in RAW264.7 mouse macrophages was investigated. In the DNCB­induced AD mouse model, LLT inhibited infiltration by mast cells, eosinophils and CD8+ cells in the dorsal skin tissue of AD mice, and suppressed the expression of IgE and IL­6 in serum. In addition, LLT inhibited the phosphorylation of ERK and JNK, as well as NF­κB in skin tissue. In the HaCaT cell model induced by TNF­α/IFN­Î³, LLT inhibited the expression of thymus and activation­regulated chemokine, granulocyte­macrophage colony­stimulating factor, monocyte chemoattractant protein­1, TNF­α and IL­1ß, whilst inhibiting the phosphorylation of NF­κB. In addition, in the lipopolysaccharide­induced RAW 264.7 cell inflammation model, LLT inhibited the expression of TNF­α and IFN­Î³, the nuclear translocation of NF­κB and the phosphorylation of ERK and JNK. These results suggested that LLT may be a promising candidate for the treatment of inflammatory dermatitis.