IL6 and major depressive disorder: The results showed that Alzheimer disease caused anxiety-like and depression-like behaviors (p = 0.000), decreased the concentrations of BDNF (p = 0.000) and FRAP (p = 0.000), increased the concentration of MDA (p = 0.000), and increased the expressions of IL-1β (p = 0.000), TNF-α (p = 0.000), and IL-6 (p = 0.000).