ICL1-9-mediated protection against I/R-induced injury is β2AR- and β-arrestin-dependent. Representative images of hearts from WT controls versus β2ARKO (A) or βarr1KO and βarr2KO (F) mice that received Scr or ICL1-9 pepducin at the time of I/R, stained with Evan's Blue/TTC 24 h following I/R injury. Quantification of (B, G) the area at risk (AAR) expressed as percentage of the total LV area and (C, H) infarct size expressed as a percentage of the AAR for WT controls versus β2ARKO (B-C) or βarr1KO and βarr2KO (G-H) mouse hearts. Representative TUNEL staining (red) within the AAR of WT controls versus β2ARKO (D) or βarr1KO and βarr2KO (I) mouse hearts. Hearts were counterstained for troponin I (TNNI, green) to label cardiomyocytes and DAPI (blue) to identify nuclei. Quantification of TUNEL+ cardiomyocytes expressed as a percentage of the total number of cardiomyocytes for WT versus β2ARKO (E) or βarr1KO and βarr2KO (J) mouse hearts. For (A-E): n=7 Scr WT, n=7 ICL1-9 WT, n=10 Scr β2ARKO, n=11 ICL1-9 β2ARKO. For (F-J): n=18 Scr WT, n=10 ICL1-9 WT, n=10 Scr βarr1KO, n=10 ICL1-9 βarr1KO, n=11 Scr βarr2KO, n=10 ICL1-9 βarr2KO. * p < 0.05, ** p < 0.01, one-way ANOVA with Tukey's multiple comparison test.