Figure 1

Activation of microglia by BDV infection prior to neuronal loss in the hippocampus. (A) No ED1+ cells in the section from a mock-infected rat, 10 dpi. Scale bar – 35 um; dg – the dentate gyrus; h – the hilus area. (B) BDV infection produces a significant increase in the number of ED1+ cells in the dentate gyrus. The white squares depict the areas where ED+ cells were counted; dg – the dentate gyrus; h – the hilus area; arrows point to ED1+ activated microglia cells; 10 dpi. (C) BDV-infection in neurons of the hippocampus. Double-immunostaining of the brain section from a BDV-infected rat at 10 dpi. Note BDV-positive (brown) staining in neurons (arrows) and GFAP-positive (purple) staining in astrocytes (arrowheads). Scale bar – 25 μm; dg – the dentate gyrus. (D) The quantitative analysis of ED1+ cells in the dentate gyrus of the hippocampus in mock-(open bars) and BDV-infected (solid bars) rats. Note a significant increase in the number of activated microglia cells as early as 10 dpi. * – p < 0.05 vs. mock-infected animals. (E) The quantitative estimate of the number of granule cells in the dentate gyrus of the hippocampus in mock-(open bars) and BDV-infected (solid bars) rats. Note that a significant decline in the number of granule cells was not observed until 30 dpi. * – p < 0.05 vs. mock-infected animals. (F) The quantitative estimate of the volume of the dentate gyrus of the hippocampus in mock-(open bars) and BDV-infected (solid bars) rats. Note that a significant decrease in the volume of the dentate gyrus of the hippocampus was not seen until 30 dpi. * – p < 0.05 vs. mock-infected animals.