Figure 6.

Microglial elimination in thy1-GFP-M expressing CaM/Tet mice: 5- to 8-month-old GFP-CaM/Tet mice (C57BL/6-CBA mix) were treated with 290 mg/kg PLX3397 for 2 months to deplete microglia. A 25 d neuronal lesion was induced in one-half of the animals at the same time treatment with PLX3397 began. A, B, Schematics of GFP-CaM/Tet mouse model of inducible neuronal loss and experimental design. C, Representative 10× confocal images of the hippocampal region from each group for neuronal nuclei (NEUN in blue channel), microglia (IBA1 in red channel), and GFP in the green channel. D, Representative 63× IBA1 immunofluorescent staining from the hippocampal region showing rod like morphologies with lesion. E, Quantification of microglia in the field-of-view by automated, direct cell counting reveals a significant decrease in both PLX3397-treated groups. F, Estimation of microglia per hippocampus by stereological methods also reveals a significant decrease in both PLX3397-teated groups. G, Quantification of the thickness of the hippocampal layers reveals a significant lesion-induced decrease only in the stratum radiatum. H, Representative 20× pictures of Cresyl Violet staining in the CA1 cell layer from each group. I, Stereological estimation of neurons in the CA1 region from each group reveals a significant decrease only in the lesion + PLX3397 group. J, Lesion mice did not display a deficit in performance on elevated plus maze. Symbols denote significant differences between groups (p < 0.05): †control versus PLX3397; *control versus lesion; φPLX3397 versus lesion + PLX3397; #lesion versus lesion + PLX3397. Error bars indicate SEM; n = 5–6/group.