Fig. 5

Loss of mushroom spines and synaptic integrity is reversed by normalized RyR-Ca²⁺ in 3xTg-AD neurons. a Top: Images show Lucifer Yellow-filled dendrites and spines from saline- and Ryanodex-treated NonTg and 3xTg-AD CA1 neurons. Bottom: Bar graphs show a significant loss of mushroom spines in the 3xTg-AD mice, and a restoration of mushroom spine number after Ryanodex treatment in 3xTg-AD neurons. (Saline treated: NonTg n = 8 neurons/3 mice; 3xTg-AD n = 6 neurons/3 mice. Ryanodex treated: NonTg n = 4 neurons/3 mice; 3xTg-AD n = 8 neurons/3 mice; 2–5 dendritic primary or secondary branches from each cell). b Top: Confocal images (40x, single plane, axial resolution < 0.3 μm) show colocalized immunolabeling of postsynaptic PSD (postsynaptic density, red) and presynaptic (synaptophysin, green) proteins at the CA3-CA1 synapses from saline- and Ryanodex-treated NonTg and 3xTg-AD mice. Inset: higher magnification (100x) detailing synaptic labeling patterns in each condition, with yellow fluorescence indicating close localization of pre- and postsynaptic markers in the merged images. Bottom: Bar graphs show a reduction of synaptophysin and PSD95 labelling, and colocalization of pre- and postsynaptic proteins in the saline-treated 3xTg-AD mice, and that Ryanodex-treatment results in the recovery of these synaptic proteins in 3xTg-AD mice, and has no effects in the NonTg mice. (NonTg n = 36 slices/6 mice for each treatment condition; 3xTg-AD n = 36 slices/6 mice for each treatment condition). Data are presented as Mean ± SEM; *p < 0.05, **p < 0.01 and ***p < 0.001 represent significantly different from saline-treated 3xTg-AD