Figure 2. ChGn‐2^‐/‐ (chondroitin sulfate N‐acetylgalactosaminyltransferase‐2) mice exhibit severe left ventricle dysfunction after acute pressure overload.

A, Representative echocardiographic images in wild‐type (WT) and ChGn‐2^‐/‐ mice in either sham or transverse aortic contriction (TAC) group 2 weeks after surgery. White bars: 200 msec; red bars: 2 mm. B, Left ventricular systolic function was analyzed by the fractional shortening at day 0, 3, 7, 10, and 14 days after TAC (n=6 for sham WT, n=5 for sham ChGn‐2^‐/‐, n=8 for TAC WT, n=8 for TAC ChGn‐2^‐/‐). Kruskal‒Wallis test followed by Wilcoxon rank‐sum test was used to analyze the difference of fractional shortening between the groups at each time point. ^$$ P<0.01 between sham WT and TAC WT. ⁺⁺ P<0.01 between sham ChGn‐2^‐/‐ and TAC ChGn‐2^‐/‐. ^%% P<0.01 and ^%%% P<0.001 between TAC WT and TAC ChGn‐2^‐/‐. C, Left ventricular systolic function was analyzed by the ejection fraction at day 0, 3, 7, 10, and 14 days after TAC (n=6 for sham WT, n=5 for sham ChGn‐2^‐/‐, n=8 for TAC WT, n=8 for TAC ChGn‐2^‐/‐). Kruskal‒Wallis test followed by Wilcoxon rank‐sum test was used to analyze the difference of ejection fraction between the groups. ^$$ P<0.01 between sham WT and TAC WT. ⁺⁺ P<0.01 between sham ChGn‐2^‐/‐ and TAC ChGn‐2^‐/‐. ^%% P<0.01 and ^%%% P<0.001 between TAC WT and TAC ChGn‐2^‐/‐. D, Representative images for transversal section of the heart of WT and ChGn‐2^‐/‐ mice in either sham or TAC group 2 weeks after surgery; bars: 500 μm. E, Representative images for Masson trichome staining of the heart in WT and ChGn‐2^‐/‐ mice in either sham or TAC condition; bars: 200 μm. F, Quantification of heart weight normalized to body weight in WT and ChGn‐2^‐/‐ mice in either sham or TAC condition (n=13 for sham WT, n=10 for sham ChGn‐2^‐/‐, n=17 for TAC WT, n=15 for TAC ChGn‐2^‐/‐). G, Quantification of heart weight normalized to tibia length in WT and ChGn‐2^‐/‐ mice in either sham or TAC condition (n=13 for sham WT, n=10 for sham ChGn‐2^‐/‐, n=17 for TAC WT, n=15 for TAC ChGn‐2^‐/‐). H, Quantification of collagen fibrosis area (%) in the heart of WT and ChGn‐2^‐/‐ mice in either sham or TAC group 2 weeks after surgery (n=6 for sham WT, n=5 for sham ChGn‐2^‐/‐, n=8 for TAC WT, n=8 for TAC ChGn‐2^‐/‐). I, Quantitative real time polymerase chain reaction analysis for collagen‐1a (Col1a1) in the heart of WT and ChGn‐2^‐/‐ mice in either sham or TAC group 2 weeks after surgery (n=6 for sham WT, n=5 for sham ChGn‐2^‐/‐, n=8 for TAC WT, n=8 for TAC ChGn‐2^‐/‐). J, Representative images for TUNEL (terminal deoxynucleotidyl transferase dUTP nick end labeling) and cTnT (cardiac troponin T) double immunofluorescence staining in the heart of WT and ChGn‐2^‐/‐ mice in either sham or TAC group 2 weeks after surgery. TUNEL and cTnT double‐positive apoptotic cells was quantified (n=5 for each group); bars: 50 μm. TUNEL, green; cTnT, red; and 4’,6‐diamidino‐2‐28 phenylindole dihydrochloride, blue. K, Immunoblotting for caspase‐3, cleaved caspase‐3 (c.caspase 3), and GAPDH in the heart of WT and ChGn‐2^‐/‐ mice in either sham or 2 weeks after TAC. Molecular weight (MW) for protein ladders are shown. Apoptosis was assessed by the cleaved caspase‐3 expression levels (n=6 for each group). Quantitative data show cleaved caspase 3/total caspase 3 value relative to that in sham WT group. Data represent median and interquartile range. *P<0.05, **P<0.01, ***P<0.001, and ****P<0.0001. Statistical analyses were performed using Kruskal‒Wallis test followed by Wilcoxon rank‐sum test (F, G, H, I, J, and K). 18s indicates 18s ribosomal RNA; BW, body weight; ChGn‐2, chondroitin sulfate N‐acetylgalactosaminyltransferase‐2; cTnT, cardiac troponin T; DAPI, 4’,6‐diamidino‐2‐28 phenylindole dihydrochloride; ChGn‐2, chondroitin sulfate N‐acetylgalactosaminyltransferase‐2; EF, ejection fraction; HW, heart weight; TAC, transverse aortic constriction; TL, tibia length; TUNEL, terminal deoxynucleotidyl transferase dUTP nick end labeling; and WT, wild‐type.