Fig. 1: The presence of soluble Tau-Cy5 does not alter the gross morphology of the DG

(a) Schematic diagram of the experimental design. Animals received a stereotaxic injection of either Tau-Cy5 (13) or PBS-Cy5 (13) in the hippocampal dentate gyrus (DG). Of these animals, eight (four Tau-Cy5 and four PBS-Cy5) also received an injection of an RFP-expressing retrovirus in order to label newborn granule neurons (group A). The remaining 18 animals (9 Tau-Cy5 and 9 PBS-Cy5) formed the group B. Of these animals, six (three Tau-Cy5 and three PBS-Cy5) were used for electron microscopy analyses. Animals were sacrificed 8 weeks after stereotaxic injections. (b) Representative tile-scan images of the whole hippocampus of PBS-Cy5- and Tau-Cy5-injected mice. An intense Cy5 signal can be observed 8 weeks after Tau-Cy5 injection, but not after PBS-Cy5 injection. (c) Quantification of DG volume in PBS-Cy5- and Tau-Cy5-injected mice. (d) Number of apoptotic fractin⁺ cells in the DG. (e, f) Representative images (e) and quantification (f) of the number of mature granule neurons in PBS-Cy5- and Tau-Cy5-injected mice. Tau-Cy5 injection did not lead to differences in any of these general morphometric parameters. In (d, f) graphs represent mean ± SEM; n = 6 mice per experimental condition. DG, dentate gyrus; GL, granular layer; H, hilus. White scale bar: 300 µm. Red scale bar: 50 µm. Green scale bar: 10 µm