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Figure 3. GSK-3β^S9A knock-in (βKI) attenuates cardiac hypertrophy, fibrosis, apoptosis, and senescence during aging. (A) Left ventricular weight (LVW)/body weight (BW) in WT and homozygous βKI. *P < 0.05 vs. the same genotype at six months (6); ^#P < 0.05 vs. WT24. (B) Wheat germ agglutinin staining of cardiac tissue sections from WT and homozygous βKI. Scale bar = 100 μm. (C) Cardiomyocyte cross-sectional area of WT and homozygous βKI. *P < 0.05 vs. WT6; ^#P < 0.05 vs. WT24. (D) Picric acid Sirius red (PASR) staining in WT and homozygous βKI mice. Scale bar = 200 μm. (E) Percent cardiac fibrosis out of total image area in WT and homozygous βKI. *P < 0.05 vs. the same genotype at six months (6); ^#P < 0.05 vs. WT24. (F) TUNEL and DAPI staining in WT and homozygous βKI. Arrows point to positive TUNEL-stained nuclei. Scale bar = 100 μm. (G) Percent of TUNEL-positive nuclei in WT and homozygous βKI mice. *P < 0.05 vs. WT6; ^#P < 0.05 vs. WT24. (H) Senescence marker pH2AX in WT and βKI mice at 6 and 24 months old (M). Green, cardiac troponin T. Red, pH2AX; Blue, DAPI. Arrows point to positively stained nuclei. Scale bar = 20 μm. (I) The percent of pH2AX-positive cardiomyocytes in WT and βKI. *P < 0.05 vs. WT at six months (WT6); ^#P < 0.05 vs. WT at 24 months (WT24). (J) Immunoblots of pH2AX, H2AX, and α-tubulin in left ventricular homogenates of WT and βKI. (K) Relative band density of pH2AX/H2AX. *P < 0.05 vs. WT6; ^#P < 0.05 vs. WT24. WT: Wild type.