Effect of isoflurane preconditioning on myocardial ischemia-reperfusion injury induced by antioxidative remodeling in aged rats

Abstract

Objective To evaluate the effect of isoflurane preconditioning on myocardial ischemia-reperfusion (I/R) injury induced by antioxidative remodeling in aged rats. Methods Fifty-six SPF aged male Sprague-Dawley rats, aged 22-24 months, weighing 420-480 g, were divided into 5 groups by a random number table method: sham operation group (S group, n=16), oxygen free radical scavenger tempol group (T group, n=16), myocardial I/R group (I/R group, n=8), tempol plus myocardial I/R group (TI group, n=8), and tempol plus isoflurane preconditioning plus myocardial I/R group (TII group, n=8). Tempol 125 mg·kg-1·day-1 was intraperitoneally injected for 4 weeks in group T. Myocardial I/R was induced by ligation of anterior descending branch of left coronary artery for 30 min followed by 2-h reperfusion to establish myocardial I/R injury model in group I/R.The model was established after antioxidant treatment in group TI.In group TII, 1.5% isoflurane was inhaled for 30 min followed by 15-min washout, and then the model was established.Animals were sacrificed at the end of reperfusion, and the left ventricle was obtained for determination of the percentage of myocardial infarct size (by TTC staining), glutathione(GSH)and oxidized glutathione(GSSG) concentrations and superoxide dismutase(SOD)activity in S and T groups (by enzyme-linked immunosorbent assay), and expression of Cu/ZnSOD, MnSOD and nitrotyrosine in S and T groups (by Western blot). Results Compared with S and T groups, the percentage of myocardial infarct size was significantly increased in I/R, TI and TII groups (P 0.05), the expression of GSSG and nitrotyrosine was down-regulated, the GSH/GSSG ratio was increased, the activities of total SOD and MnSOD were increased, and the expression of MnSOD was up-regulated in group T (P<0.05). Conclusion Isoflurane preconditioning can reduce myocardial I/R injury induced by antioxidative remodeling in aged rats. Key words: Isoflurane; Antioxidants; Aged; Myocardial reperfusion injury