Fig. 2

Increased number of neurons in anti-aggregant Tau^RDΔKPP organotypic hippocampal slice culture. a OHSCs were prepared from control, anti-aggregant Tau^RDΔKPP and pro-aggregant Tau^RDΔK pups aged P8. Slices were fixed at DIV30 and immunostained with NeuN antibody. Overview image of a single slice aged DIV30 from the controls, anti-aggregant Tau^RDΔKPP and the pro-aggregant Tau^RDΔK shows a 30% increase of hippocampal size in the anti-aggregant Tau^RDΔKPP slice compared to the age-matched controls. On the contrary the pro-aggregant Tau^RDΔK slice shows a similar size of the hippocampus as in the controls but with intense neuronal loss in the CA3 region. Scale bar 200μm. b Representative image of the CA1, CA3 and DG regions of the hippocampus stained with NeuN from controls, anti-aggregant Tau^RDΔKPP and pro-aggregant Tau^RDΔK slices. Scale bar 50μm. Cell bodies of pyramidal neurons in the CA region and the granular neurons in the DG region are clearly distinguishable. c Graph showing the number of NeuN⁺ cells per counting frame in the different regions of the hippocampus. An increase by 47% of the number of NeuN⁺ cells is observed in the CA1, 69% in CA3 and 81% increase in neuronal number in DG in the anti-aggregant Tau^RDΔKPP slices (pink bars) when compared to the controls (grey bars). By contrast, the pro-aggregant Tau^RDΔK slices (blue bars) show 44% reduced neuronal number in the CA1, 33% reduced neuronal number in CA3 and 22% DG compared to the age matched controls (grey). Results are given as mean ±SEM of 10 animals and 4-6 slices per animal. Data were analyzed by Student's t-test. *p<0.05, ***p<0.001 ****p<0.0001 compared to control slices