However, TNF-α, IL-1B, and IL-6 secretion in DD group was significantly enhanced than that in depression and diabetes group (P < 0.05, P < 0.01); CX3CR1 blocker treatment of DD group significantly reduced the levels of TNF-α, IL-1B, and IL-6 in hippocampus of all groups (P < 0.05, P < 0.01). This evidence concerns the gene CX3CR1 and major depressive disorder.