Moreover, the results of Western blot showed that hucMSC‐exosomes in H‐EXO and L‐EXO could distinctly inhibit the expression of apoptosis protein BAX in CVB3‐induced myocarditis mice, but just hucMSC‐exosome (50 μg, H‐EXO) could enhance the anti‐apoptosis protein Bcl‐2 in CVB3‐induced myocarditis mice (Figure 4C,D). The gene discussed is BCL2; the disease is myocarditis.