Fig. 3

Cardiac damage in hearts from DOX/TRAZ treated tumor-bearing mice compared to untreated mice. a Images of heart sections after Masson’s trichrome (top row) staining at the indicated times: no treatment, 2 months treatment or 4 months treatment. Bottom row: Images of heart sections used to calculate percentage of fibrosis (indicated on images) by ImageJ. b Picrosirius red staining of heart section after the indicated treatment shows the distribution of collagen fibers in thin layers of connective tissue surrounding cardiomyocytes and blood vessels in untreated heart. Magnified image of no treatment section shows a normal thin layer of connective tissue under the smooth with arrow indicating intact endothelial lining. Magnified image from 2 months of treatment indicate increased collagen in connective tissue layer surrounding blood vessels from treated hearts and a disruption of the endothelial lining of vessels, showing an uneven surface and swollen, necrotic cells (arrows). c Quantification of Cardiac troponin I (cTnI) and Brain naturetic protein (BNP) levels by ELISA revealing elevated cTnI levels in serum from DOX/TRAZ treated mice compared to untreated controls (n = 5), ** p < 0.01, Student’s T-test. Control = 0.113 ng/ml; 2 months treatment = 5.45 ng/ml (n = 4); 3 months = 3.46 ng/ml (n = 3); 4 months = 1.88 ng/ml (n = 4) cTnI. BNP was elevated in serum from DOX/TRZ treated mice after 4 months treatment as compared to untreated controls; control = 4.04 ng/ml BNP (n = 5); treated = 7.52 ng/ml (n = 6), *p < 0.05, Student’s T-test. Mice in A were treated as described in study design I, mice in B were treated as described in study design II (see Table 1 in Methods)