Figure 6

DOX administration turns off transgene expression and restores the structure of the dentate gyrus in IKK2^nCAanimals. (A) Experimental design indicating schedule of DOX administration to mice for transgene inactivation. (B) Representative image of Co and IKK2^nCA animals (treated as indicated) obtained by IVIS (upper panel). Quantification of in vivo luciferase activity demonstrates inactivation of transgene expression in IKK2^nCA mice by DOX application (lower panel; n = 4). All p-values are derived from two-tailed-unpaired student’s t test. (C) Cresyl violet stained sections show restoration of the DG morphology in IKK2^nCA mice after administrating DOX for 3 months. Quantification of cell number reveals that the number of neurons in GCL of IKK2^nCA mice recovers upon DOX treatment. All p-values are derived from two-tailed-unpaired student’s t test (n = 4). (D) Representative images from DG of IKK2^nCA mice indicate reversal of Bdnf expression after transgene inactivation. Arrows are pointing towards the hilus of the DG indicating Bdnf expression. Quantification of Bdnf immunoreactivity indicates reversal of Bdnf expression in the dentate hilus of IKK2^nCA mice after DOX treatment. P-values are derived one-way ANOVA Bonferroni’s Multiple Comparison test (n = 4). (E) Co-immunostaining of brain sections with hIKK2 transgene (red), and NeuN (green) demonstrating that only GCL neurons express hIKK2 (white arrows) whereas NeuN positive neurons in the hilus of DG (arrow heads) do not show any transgene expression (co-expression is shown in yellow). All fluorescent images show DAPI (blue) costaining. (A-E) Co = wild type and single transgenic littermates, IKK2^nCA = transgenic mice with neuron-specific expression of constitutively active IKK2. Scale bars: B, E: 50 μm, C: 100 μm. All data are shown as mean ± SEM. * p < 0.05, ** p < 0.01.