Fig. 3

Exosomes from breast cancer cells exacerbate DOX-induced cardiomyocyte pyroptosis in vivo. a Schematic illustration of the subchronic DOX exposure model in mice to test the injury efficacy of D-BCC-EXOs (n = 5). b Representative images of M-mode echocardiography and blood flow velocity (obtained using a Doppler system) in mice. c, d The E/A and the E/E’ ratios were quantified using the Doppler echocardiography. e, f Quantification of the left ventricular (LV) ejection fraction and LV fractional shortening via M-mode echocardiography (n = 5). g Representative images of hematoxylin-eosin (H&E) staining (upper), Sirius red staining indicating myocardial fibrosis (middle), and wheat germ agglutinin (WGA) immunofluorescence staining (lower). Scale bar: 50 μm. h Statistics of vacuolization in ventricular tissues. i The fibrotic area per left ventricle was quantified via Sirius red staining (n = 5). j Cell size was quantified via WGA immunofluorescence staining (n = 5). k Mouse plasma brain natriuretic peptide (BNP) was measured using a colorimetric method (n = 5). l–o Pyroptosis-related protein levels in mouse ventricular tissue were assessed via western blotting (n = 5) (one-way ANOVA was used to compare all experimental groups to the DOX group). “E” indicates early diastolic transmitral flow velocity, “E′” indicates early diastolic mitral annular velocity, and “A” indicates late (atrial) diastolic transmitral flow velocity. D-BCC-EXOs, denotes doxorubicin-treated breast cancer EXOs, “N-BCC-EXOs” denotes normal breast cancer cell EXOs, “D-BCC-EXOs” denotes DOX-induced breast cancer cell EXOs, “ns” indicates non-significant, and “DOX” indicates doxorubicin. Data are presented as means ± SD