Research Paper Advance Articles

Loss of β-catenin via activated GSK3β causes diabetic retinal neurodegeneration by instigating a vicious cycle of oxidative stress-driven mitochondrial impairment

Figure 4. Restoring β-catenin by GSK3β inhibition protects diabetic retinae from mitochondrial and synaptic defect. (A) Western blotting analyses of phosphorylated-Akt (S473), Akt, phosphorylated-GSK3β (S9), and GSK3β in retinae from mice fed with RD or HFD, respectively. Relative intensities were quantified and normalized against the level of Akt or GSK GSK3β, respectively. (BI) si-GSK3β was intravitreally injected in the left eye of HFD-fed mice (HFD-L/si-GSK3β), while a scramble si-sc was injected in the contralateral right eye as a control (HFD-R/si-sc). (B) Western blotting for GSK3β and active β-catenin. Relative intensities were quantified. (C) Representative waveforms of VEP and quantification of differences in peak amplitude (N1-P1). (D) Retinal immunostaining for synaptophysin (green; scale bar, 100 μm). Areas boxed in are shown at higher magnification. (E) Representative images of retinal SEM. Lower panels are high-power magnification of boxed areas. Scale bar, 10 μm. (F) Relative mRNA expression of ROS scavenging genes in retinae. (G) Activities of antioxidant enzymes in retinae. (H) Contents of retinal 4-HNE. (I) Representative images of retinal TEM with mitochondria in IPL (arrows). Areas boxed in are shown at higher magnification. Scale bar, 0.5 μm. Data are means ± SEM. n = 4 mice (A) or n = 4 eyes (BI) per group. *P < 0.05 and **P < 0.01 vs age-match RD controls; *P < 0.05 and **P < 0.01 vs contralateral eye injected with scramble si-sc. NS, no significant difference. See also Supplementary Figures 2D and 3D.