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. Author manuscript; available in PMC: 2019 Jun 7.
Published in final edited form as: Radiat Res. 2017 Jun 14;188(2):191–203. doi: 10.1667/RR14667.1

FIG. 3.

FIG. 3.

ECHO, HEMO measurements of cardiac functions and cardiac remodeling in the radiation and aging plus MI model. Panel A: Experimental design to evaluate the effect of different sequences of whole-body fractionated low-dose 17 cGy, 1 GeV 1H and a single dose of 15 cGy, 1 GeV/nucleon 56Fe radiation in the hearts of 8–10-month-old C57BL/6NT mice at 1 month postirradiation. Radiation-induced alterations in cardiac function were assessed by echocardiography (ECHO), hemodynamic (HEMO) and morphometric/histologic measurements and activation of signaling pathways by protein analyses. Acute MI was induced by ligation of the left anterior descending coronary artery at 1 month postirradiation, and mice were monitored for 28 days after MI. Panel B: Post-MI survival data. ECHO analysis of cardiac function at 1 month postirradiation in mice for ejection fraction (EF%) and posterior wall thickness (PWth) (mm) (panels C and D, respectively). Results in all graphs (panels C and D) are presented as mean ± SEM (n = 6–8 animals per time point/group). Group 1: nonirradiated control (solid black line); group 2: 1H × 3 irradiation (solid green line); group 3: 1H × 3 + 56Fe irradiation (solid blue line); group 4: 56Fe + 1H × 3 irradiation (solid red line). HEMO measurements and analysis of cardiac function at 1 month postirradiation in a radiation and aging plus MI model for LV end-systolic pressure (LVESP) (mmHg), LV end-diastolic pressure (LVEDP) (mmHg) and LV dP/dtmax and dP/dtmin (mmHg/s) (panels E–G, respectively). Cardiac remodeling at 1 month postirradiation and day 28 after MI was measured using Masson’s trichrome staining (panel H), where blue indicates fibrosis, e.g., the infarction remodeling. Measurements represent midline length of the infarction when >50% of the LV was involved (mm) and every third section of the adjacent 8-μm-size section was measured and infarction size was reconstructed as described above. Insets (panel H) are representative images of nonirradiated control mice and mice that were whole-body irradiated using different sequences. Panel I: Graphic representation of the infarction size/scar (mm2) at 1 month postirradiation and 28 days after MI. Results in all graphs (panels C–G, I) are presented as mean ± SEM (n = 6–8 animals per time point/group). Statistical significance was assigned when P < 0.05.