Fig. 1: Retnla knockout protects mouse heart from myocardial infarction injury.

A Survival rates of the experimental groups; wild type (WT, n = 15) mice and Retnla knockout (KO, n = 17) mice with or without myocardial infarction (MI). WT MI n = 47, KO MI n = 36. B Left ventricular ejection fraction (LVEF) was determined by echocardiography in Retnla KO (n = 19) and WT littermates (n = 18) 14 days after MI. C Heart weight/body weight (HW/BW) ratios of mice were calculated before and at 14 days after MI. (WT; n = 7, KO; n = 7, WT MI; n = 18, KO MI; n = 16). D Cardiomyocyte apoptosis (white arrows) in the peri-infarct area was determined by TUNEL staining. cTnI cardiac troponin I. Scale bar, 200 μm. (WT; n = 7, KO; n = 7). E Inflammation-related mediators were analyzed by using antibody array membranes. F Three days after MI, cardiac macrophages were isolated to compare the cell number and phenotype. Ly6G(−)CD11b(+)F4/80(+)CD11C(−) cells are pro-inflammatory macrophages and Ly6G(−)CD11b(+)F4/80(+)CD206(+) cells are anti-inflammatory macrophages. The number of Ly6G(−)CD11b9(+)F4/80(+) cardiac macrophages was higher in the KO mice (n = 3, three mice per sample each) than in the WT mice (n = 3, three mice per sample each). G Angiogenesis-related mediators were analyzed by using antibody array membranes. H Microfil perfusion of hearts from WT and Retnla KO mice with MI for 14 days. I Left ventricular vascularity was assessed by immunostaining of von Willebrand factor (vWF) and α-smooth muscle actin (α-SMA). Representative images of vWF stained capillaries and α-SMA(+)-vessels in the infarcted heart. (WT; n = 7, KO; n = 10). Scale bar, 100 μm. J Representative Masson’s trichrome staining images of WT (n = 17) and Retnla KO mice (n = 15) after 14 days of MI. Quantitative analysis of ventricular fibrosis (expressed as a percentage of total left ventricular area) in WT and KO. Scale bar, 1000 μm. EF ejection fraction, FS fractional shortening. Data are represented as mean ± SEM. #P < 0.05, ##P < 0.01, ###P < 0.001 (by Student’s t test).