Comparative effects of ischemic pre and postconditioning on ischemia-reperfusion injury in spontaneously hypertensive rats (SHR) |
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Authors: | Fantinelli Juliana C Mosca Susana M |
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Institution: | (1) Centro de Investigaciones Cardiovasculares, Universidad Nacional de La Plata, La Plata, Buenos Aires, Argentina |
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Abstract: | Brief episodes of myocardial ischemia-reperfusion applied early in reperfusion may attenuate the reperfusion injury, strategy
called ischemic postconditioning (IPO). Our objective was to examine the effects of IPO compared with ischemic preconditioning
(IP) on postischemic myocardial dysfunction in spontaneously hypertensive rats (SHR). Isolated hearts from SHR and normotensive
WKY rats were subjected to the following protocols: (1) Ischemic control (IC): global ischemia 20 min (GI20) and reperfusion
30 min (R). (2) IPO: three cycles of R30sec–IG30sec at the onset of R; (3) IP: a cycle of IG5–R10 previous to GI20, (4) IPO
in the presence of chelerythrine, an inhibitor of protein kinase C (PKC). Systolic and diastolic function were assessed through
developed pressure (LVDP) and end diastolic pressure (LVEDP), respectively. Lipid peroxidation was estimated by thiobarbituric
reactive substance (TBARS) concentration. IPO significantly improved postischemic dysfunction. At the end of R, LVDP recovered
to 87 ± 7% in WKY and 94 ± 7% in SHR vs. 55 ± 11% and 58 ± 12% in IC hearts. LVEDP reached values of 24 ± 6 mmHg for WKY and
24 ± 3 mmHg for SHR vs. 40 ± 8 and 42 ± 5 mmHg in IC hearts. Similar protection was achieved by IP. TBARS contents of SHR
hearts were significantly diminished by IP and IPO. PKC inhibition aborted the protection of myocardial function and attenuated
the diminution of lipid peroxidation conferred by IPO. These data show that IPO was as effective as IP in improving the postischemic
dysfunction of hearts from SHR hearts, and that this cardioprotection appears to be associated with a diminution of ROS-induced
damage involving the PKC activation. |
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Keywords: | ischemic postconditioning ischemic preconditioning SHR TBARS |
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