Osthole Attenuates Mouse Atopic Dermatitis by Inhibiting Thymic Stromal Lymphopoietin Production from Keratinocytes

Atopic dermatitis is one of the most common skin diseases. Dysregulation of immune system and chronic inflammation were believed to be associated with atopic dermatitis. Osthole was reported to play important roles in antitumor and anti-inflammation. However, whether osthole has effects on atopic dermatitis remains unclear. In this present study, we explored the biological role of osthole in atopic dermatitis and the molecular mechanism. Atopic dermatitis was induced by 2,4-dinitrochlorobenzene. Pathological damage of ear was detected by H&E staining. IgE level in serum or thymic stromal lymphopoietin (TSLP) level in supernatant was detected by ELISA. Interleukin (IL)-4 expression and IL-13 expression in CD4 T cells were detected using flow cytometry. The expression levels of mRNA or protein levels were detected by RT-PCR or Western blot. Osthole attenuated atopic dermatitis development in mouse model. Osthole inhibits Th2 cell response, but have on influence on Th1 or Th17 cell response in the skin. In mouse model, osthole treatment significantly inhibited atopic dermatitis via directly inhibiting TLSP expression levels in keratinocytes. Osthole treatment alleviates atopic dermatitis through directly down-regulating TSLP production from keratinocytes. Osthole may serve as a potential choice for atopic dermatitis treatment in clinic.