Figure 3. Dendritic spine morphology is partially rescued in Fmr1^KO/App^HET or MPEP treated Fmr1^KO mice.

(A) Representative fluorescent images of primary cultured neurons prepared from WT (upper left), Fmr1^KO (upper right and lower left) and Fmr1^KO/App^HET (lower right) embryos stained with DiI and visualized by fluorescent microscopy (100× objective). The arrows denote dendritic spines. (B) The lengths of dendritic protrusions were quantitated with StereoInvestigator software and plotted against mouse strain/treatment. The percentage of filopodia versus spines for each condition is given below the histogram. Statistics: one-way ANOVA comparison of the three genotypes (untreated) p<0.0001, F = 27.18. All genotypes are statistically different from each other by Student T-Test and Bonferroni's multiple comparison tests. Two-way ANOVA comparison of WT versus Fmr1^KO ± MPEP: p<0.0001, F = 12.89 (interaction), F = 35.01 (genotype) and F = 27.62 (MPEP). The untreated and 15 min MPEP treated WT spines are statistically different from the corresponding Fmr1^KO spines by the Bonferroni multiple comparison test (p<0.5). Stars (★) denote statistically different spine lengths by Student T-test analyses (p<0.5). Error bars indicate SEM [Fmr1^KO: untreated (n = 746 spines), 15 min MPEP (n = 263), 1 hr MPEP (n = 300), 4 hr MPEP (n = 293); WT: untreated (n = 994), 15 min MPEP (n = 535), 1 hr MPEP (n = 373), 4 hr MPEP (n = 1221); Fmr1^KO/App^HET (n = 2469)].