IL6 and major depressive disorder: Transplantation of CSS/RS-treated mouse feces, which were collected 2 days after the final CSS treatment in RS-exposed mice to prepare CSS-free feces, and oral gavage of CSS suppressed RS-induced anxiety, depression, and colitis in the transplanted mice: they significantly alleviated anxiety- and depression-like behaviors, suppressed NF-κB activation and BDNF and IL-6 expression in the hippocampus.