Attenuation of Isoflurane Preconditioning-Induced Acute Cardioprotection in Hypertensive Hypertrophied Hearts

Objectives: To evaluate the efficiency of isoflurane-induced anesthetic preconditioning and the role of mitochondrial manganese superoxide dismutase (MnSOD) in hypertensive hypertrophied hearts. Design: A prospective animal investigation. Setting: Medical center hospital research laboratory. Participants: Male spontaneously hypertensive rats (SHRs) and normotensive control Wistar-Kyoto (WKY) rats. Interventions: All pentobarbital-anesthetized open-chest rats were subjected to a 45-minute left coronary artery occlusion followed by a 120-minute reperfusion. Before ischemia, both SHR and WKY rats were assigned randomly to receive a 30-minute exposure to 0.9% saline or 1.0 minimum alveolar concentration isoflurane. Measurements and Main Results: The myocardial infarct size, assessed as a percentage of the area at risk, was significantly greater in the hypertrophied SHRs than in the WKY rats (65.3% +/- 8.7% v 51.8% +/- 7.2%, p < 0.05). Isoflurane preconditioning appreciably reduced the infarct size in the WKY hearts (30.9% +/- 10.5%, p < 0.05) but not in the SHR hearts. iVInSOD protein expression and enzymatic activity were increased drastically in response to isoflurane exposure in the hearts of the WKY rats (p < 0.05) but not in the SHRs. Conclusions: Isoflurane-induced anesthetic preconditioning is attenuated in hypertensive hypertrophied hearts. This impairment may be associated with the loss of MnSOD augmentation during ischemia and reperfusion. (C) 2016 Published by Elsevier Inc.