Similarly, the oral administration of Lactobacillus reuteri NK33 in synergistic combination with Bifidobacterium adolescentis NK98 at a dosage of 1 × 109 colony forming unit (CFU)/day significantly inhibited NF-κB activation, IL-6 expression and LPS levels, and induced hippocampal BDNF expression and CREB phosphorylation, alleviating anxiety and depression symptoms by suppressing gut dysbiosis through the inhibition of Proteobacteria in cells and in rodents [233]. Here, BDNF is linked to major depressive disorder.