Published in:
Open Access 01-12-2015 | Original research
Effect of postconditioning on dynamic expression of tenascin-C and left ventricular remodeling after myocardial ischemia and reperfusion
Published in: EJNMMI Research | Issue 1/2015
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Background
Tenascin-C (TNC), an extracellular matrix glycoprotein, is expressed transiently in distinct areas in association with active tissue remodeling. This study aimed to explore how ischemic postconditioning (PC) affects myocardial expression of TNC and ventricular remodeling using 125I-labeled anti-TNC antibody (125I-TNC-Ab) in a rat model of ischemia and reperfusion.
Methods
In control rats (n = 27), the left coronary artery (LCA) was occluded for 30 min followed by reperfusion for 1, 3, 7, and 14 days. PC (n = 27) was performed just after the reperfusion. At the time of the study, 125I-TNC-Ab (1.0 to 2.5 MBq) was injected. Six to 9 h later, to verify the area at risk, 99mTc-MIBI (100 to 200 MBq) was injected intravenously just after the LCA reocclusion, with the rats sacrificed 1 min later. Dual tracer autoradiography was performed to assess 125I-TNC-Ab uptake and area at risk. To examine the ventricular remodeling, echocardiography was performed 2 M after reperfusion in both groups.
Results
In control rats, 125I-TNC-Ab uptake ratio at 1 day after reperfusion was 3.73 ± 0.71 and increased at 3 days (4.65 ± 0.87), followed by a significant reduction at 7 days (2.91 ± 0.55, P < 0.005 vs 3 days) and14 days (2.01 ± 0.17, P < 0.005 vs 1 and 3 days). PC attenuated the 125I-TNC-Ab uptake throughout the reperfusion time from 1 to 14 days; 2.59 ± 0.59 at 1 day, P < 0.05: 3.10 ± 0.42 at 3 days, P < 0.005: 1.93 ± 0.37 at 7 days, P < 0.05: 1.40 ± 0.07 at 14 days, P < 0.001. In echocardiography, PC reduced the ventricular end-diastolic and systolic dimensions (1.00 ± 0.06 cm to 0.83 ± 0.14 cm (P < 0.05) and 0.90 ± 0.15 cm to 0.62 ± 0.19 cm (P < 0.05), respectively) and prevented a decline of ventricular percentage fractional shortening (10.5 ± 3.7 to 28.2 ± 10.7, P < 0.005).
Conclusions
These data indicate that 125I-TNC-Ab imaging may be a way to monitor myocardial injury, the subsequent repair process, and its response to novel therapeutic interventions like PC by visualizing TNC expression.