Figure 3
From: Spermidine protects from age-related synaptic alterations at hippocampal mossy fiber-CA3 synapses
Spermidine treatment rescues the age-dependent decrease in SV density selectively at MF-CA3 synapses. (a–d) Ultrastructural analysis of Mossy Fiber (MF) terminals. (a) Representative electron micrographs of MF boutons. Note the reduction in SV density in an aged Spd− bouton (black asterisk). MF bouton visible area is highlighted in light blue, spiny excrescences are highlighted in yellow. (b) Synaptic vesicles (SV) density (p = 0.0004, aged Spd−: 128.26 ± 5.11, n = 67 boutons, versus aged Spd+: 159.43 ± 5.05, n = 64; p = 0.0008, young: 163.03 ± 6.86, n = 60, versus aged Spd−; 6 mice/group; two samples Kolmogorov-Smirnov test Bonferroni corrected with α set to 0.016667). (c) Visible bouton profile indicating the synaptic bouton area visible within each image (aged Spd−: 2.69 ± 0.09, aged Spd+: 2.34 ± 0.10, young: 2.43 ± 0.13). (d) Active zone (AZ) density (aged Spd−: 2.41 ± 0.15, aged Spd+: 2.62 ± 0.16, young: 2.65 ± 0.19). Arrowheads indicate active zones, note an active zone with drastically reduced neighboring SVs in the representative electron micrograph of an aged control mouse. Values represent mean ± SEM. Graphs show medians, interquartile ranges and min/max values, circles are outliers.
