Electroacupuncture and methotrexate cooperate to ameliorate psoriasiform skin inflammation by regulating the immune balance of Th17/Treg

Abstract

Psoriasis is an autoinflammatory dermatosis, while methotrexate (MTX) is an immunosuppressant used to treat psoriasis. However, conventional immunosuppressants may cause various side effects. Acupuncture has potential benefits in treating psoriasis based on its anti-inflammatory effects. However, the immune mechanisms underlying its effects remain unclear. In this study, imiquimod-induced psoriatic mice were used to investigate the effects and mechanisms of electroacupuncture (EA) and, in particular, its joint treatment with MTX. We found that treatment with either EA or MTX ameliorated psoriasiform skin lesions, improved skin pathology and reduced proinflammatory cytokines in the skin, while joint treatment with both EA and MTX further alleviated the skin lesions and inflammation compared to either one alone. Moreover, percentages of CD4⁺ IL-17A⁺ Th17 cells in the skin and lymph nodes were decreased by EA or MTX and further lowered by combined EA+MTX treatment. Similarly, EA or MTX also reduced their RORγt expression. On the contrary, CD4⁺ FoxP3⁺ Treg frequency in psoriatic mice was augmented by EA or MTX and further increased by the joint treatment. However, depleting Tregs mostly reversed the therapeutic effects of EA or EA plus MTX. Additionally, the phosphorylated NF-κB (p65) expression was suppressed by treatment with EA, MTX or better with EA+MTX. Meanwhile, the anti-inflammatory effects of EA plus MTX were offset by an NF-κB agonist. Thus, this study has revealed that EA cooperates with MTX to balance Th17/Treg responses and to ameliorate psoriasiform skin inflammation through suppressing NF-κB activation. Our findings may be implicated for treating human psoriasis.

Keywords: Autoimmunity; Electroacupuncture; Methotrexate; Psoriasis; Regulatory T cells; Th17.