Figure 4
Normal spine morphology in KO mice. a-d, Histopathological analysis of hippocampus using thionine staining. a, naive WT mice; b, WT mice after MECS (3 h); c, naive KO mice; d, KO mice after MECS (3 h). Arrowheads, sparse and damaged area. s. ori, sriatum oriens; s. pyr, striatum pyramidale; s. rad, striatum radiatum. e-m, A biotinylated tracer was injected into the dorsal hippocampus. Pyramidal cells in cortical layer II-III were visualized using avidin and DAB. e-g, Examples of neuronal morphology. e, Low-magnification image. f, Magnified image of boxed region in (e). g, High-magnification images of the first dendritic branch of pyramidal neurons surrounded by an arrow and an arrowhead (the first branch point) in (f). Serial images at 50 nm interval. Cumulative frequency of spine length (h), spine width (i), and spine number (j). k, The average of spine length. WT, 594 spines from 5 neurons, 6–7 dendrites per neuron; KO, 501 spines from 4 neurons, 5–7 dendrites per neuron; P = 0.09, t test. l, Spine width. WT, 594 spines from 5 neurons, 6–7 dendrites per neuron; KO, 502 spines from 4 neurons, 5–7 dendrites per neuron; P = 0.49, t test. m, Number of spines. WT, 37 dendrites from 5 neurons; KO, 27 branches from 4 neurons; P = 0.12, t test. Scale bar, 1 mm (e), 100 μm (f).