To further determine the potential role of TLR4/MyD88/NF-κB signaling in depression, and to determine if the antidepressant-like behavior effects of Gps corresponded with a suppression in the signaling, we first established a model of depression by CUMS and treatment with Gps (100 or 50 mg/kg) or Flx. This evidence concerns the gene TLR4 and major depressive disorder.