Etanercept alleviates psoriasis by reducing the Th17/Treg ratio and promoting M2 polarization of macrophages

INTRODUCTION: This study aimed to investigate the effect of etanercept in psoriasis and its underlying mechanism. METHODS: Female mice were treated with imiquimod (IMQ) to induce psoriasis, and intraperitoneally administered etanercept (0.1–0.4 mg/ml). The RAW264.7 cells were treated with LPS and IFN‐γ to polarize to M1, and were treated with IL‐13 and IL‐4 to polarize to M2. RESULTS: In our study, Etanercept markedly reduced the psoriasis area and severity index scores, and epidermal thickness of mice induced by IMQ. In addition, etanercept reduced the levels of TNF‐α and IL‐6/12/23, and enhanced the levels of IL‐4/10, reduced Th17/Treg ratio and facilitated the polarization of macrophages to M2 in psoriasis model mice. Furthermore, etanercept inhibited the JAK/STAT3 pathway and increased the protein levels of SOCS1 and SOCS3. CONCLUSIONS: In conclusion, our findings indicated that etanercept could inhibit the JAK/STAT3 pathway to reduce Th17/Treg ratio and promote M2 polarization, thereby alleviating psoriasis of mice.