RTN4R and cardiac hypertrophy: To investigate the amelioration effect of NGR1 on myocardial hypertrophy, the cross-sectional areas were calculated from H & E–stained images, and the results indicated that NGR1-L and NGR1-H both substantially decreased the MI-induced cross-sectional area increment, which revealed that NGR1 relieved MI-induced myocardial hypertrophy (Figure 2A).