Fig. 4

Sequential transplantation of exosomes and the combinatorially pretreated MSCs promoted angiogenesis in the infarcted hearts. Representative images of tissue sections of α-SMA (green) staining (A) and quantification (B) of α-SMA⁺ cells per HPF at 4 weeks post-AMI (n = 5). Scale bar = 20 μm. Representative images of CD31 (green) staining (C) and quantitative data (D) of CD31⁺ cells per HPF (n = 5), Scale bar = 20 μm. All data are presented as mean ± SEM and compared by one-way ANOVA with Tukey’s test. *p < 0.05, **p < 0.01, ***p < 0.001, ****p < 0.0001 versus AMI group; ^$p < 0.05, ^$$p < 0.01, ^$$$p < 0.001 versus Exo group; ^&p < 0.05, ^&&p < 0.01, ^&&&p < 0.001, ^&&&&p < 0.0001 versus MSC group