In the present study, we found that running exercise attenuated the increases in the number of Iba1+ microglia in the CA1, CA2/3, and DG subregions of the hippocampus in the depression model rats but attenuated the increase in the density of Iba1+/CD68+ microglia only in the DG region of the hippocampus. This evidence concerns the gene CD68 and major depressive disorder.