Aged rat hearts are not more susceptible to ischemia-reperfusion injury in vivo: role of glutathione

Abstract The current study tested the hypothesis that ischemia-reperfusion (I-R) can cause more severe myocardial dysfunction and oxidative damage in senescent rats than young adult rats. Male Fischer 344 rats at the age of 6 (adult) and 24 (old) months were subjected to an open-chest heart surgery and randomly assigned to one of the following treatments: ischemia only (I), with the occlusion of the main descending branch of the left coronary artery (LCA) for 30 min; I-R, with the release of LCA occlusion for 20 min; or sham (S) operation. Heart mechanical performance was monitored using a fluid-filled catheter inserted in the right carotid artery and advanced to the left ventricle. Ischemia caused similar reductions of left ventricle systolic pressure (LVSP) and contractility (±d P /d t ) in adult and aged hearts. After I-R, adult hearts regained 82% ( P P >0.05) of LVSP. There was no significant difference in the reduction of ±d P /d t with I-R between adult and aged hearts. Old rats had lower pre-ischemic heart rate than adult rats, however, I-R caused no reduction of heart rate, and a smaller reduction of pressure-rate double product in the aged rats (10%, P >0.05) than the adult rats (23%, P