Figure 2. Demyelination and altered synaptic protein expression are observed in mouse models relevant to depression.

(A) Schematic diagram of the myelin sheath, showing the nodes of Ranvier, the paranode, and the juxtaparanode, with Caspr 1 expressed mainly in the paranode. (B) Representative images showing Caspr-positive, red-stained paranodal regions in the ventral hippocampus. Scale bar: 20 μm. n = 4 mice/group. (C) High-magnification images of Caspr staining from B. Original magnification, ×400. (D) Nodal lengths were increased in CUMS mice, based on measurements of Caspr-stained regions (n = 50 nodes from 3 different mice/group). (E) Histograms showing the frequency distribution of nodal length, which differed between control and CUMS mice. (F) Representative electron microscopic images showing demyelination in CUMS mice. Scale bar: 500 nm. (G) Thinner myelin sheaths were observed in CUMS mice, as measured by electron microscopy. The total number of myelin sheaths analyzed in the control and CUMS groups was 73 and 87, respectively (n = 15 images from 5 mice/group, t₁₅₈ = 3.361). (H and I) Representative blots showing decreased PSD95 protein expression in CUMS mice and results of the densitometric analysis. Na⁺K⁺ATPase was used as the loading control (n = 6 mice/group, t₁₀ = 3.798). (J and K) Representative blots showing decreased PSD95 protein expression in LPS-treated mice and results of the densitometric analysis (n = 6 mice/group, t₁₀ = 3.866). Data are shown as the mean ± SEM. **P < 0.01 and ***P < 0.001, by unpaired Student’s t test (D, G, I, and K).