title: Anesthetic preconditioning confers acute cardioprotection via up-regulation of manganese superoxide dismutase and preservation of mitochondrial respiratory enzyme activity.
abstract: The cellular and molecular mechanisms that underlie cardioprotection against I/R by anesthetic-induced preconditioning (APC) require further elucidation. Using isoflurane as a representative anesthetic, we evaluated the hypothesis that APC induces myocardial protection against I/R by attenuation of excessive reactive oxygen species and restoration of mitochondrial bioenergetics through postischemic up-regulation of manganese superoxide dismutase (MnSOD) expression and preservation of respiratory enzyme activity. Pentobarbital anesthetized open-chest Sprague-Dawley rats were subject to 30-min left coronary artery occlusion, followed by 120-min reperfusion. Before ischemia, rats were randomly assigned to receive 0.9% saline, two cycles of brief coronary artery occlusion and reperfusion, or a 30-min exposure to 1.0 minimum alveolar concentration isoflurane in the absence or presence of a specific mitochondrial adenosine triphosphate-sensitive potassium (KATP) channel blocker, 5-hydroxydecanoate; a membrane-permeable superoxide scavenger, 4-hydroxy-2,2,6,6-tetramethyl piperidinoxyl; or a NOS inhibitor, N(G)-nitro-L-arginine methyl ester. Isoflurane exposure induced an initial increase in myocardial superoxide (O2-), but not NO level. It also significantly decreased infarct size and restored mitochondrial respiratory enzyme activity or ATP production in I/R rat hearts, along with suppression of the O2- surge at reperfusion and increase in MnSOD expression or enzyme activity. These protective effects were abrogated by 5-hydroxydecanoate or 4-hydroxy-2,2,6,6-tetramethyl piperidinoxyl, but not by N(G)-nitro-L-arginine methyl ester pretreatment. These results suggest that opening of mitochondrial KATP channel, followed by O2- signaling, induces postischemic augmentation of MnSOD and preservation of mitochondrial respiratory enzyme activities, leading to attenuated cardiac O2- surge and restored ATP production during reperfusion, and underlie APC-induced cardioprotection.
authors: Department of Anesthesiology, Kaohsiung Veterans General Hospital, Kaohsiung, Taiwan, Republic of China.
authors: Chen Hsiu
authors: CH
authors: Chen
authors: Kang
authors: K
authors: Liu
authors: Julie Y H
authors: JY
authors: Chan
mesh_terms: D000255:Adenosine Triphosphate / Q000378:metabolism; D000777:Anesthetics / Q000494:pharmacology*; D000818:Animals; D003652:Decanoic Acids / Q000494:pharmacology; D006880:Hydroxy Acids / Q000494:pharmacology; D019157:Ischemic Preconditioning, Myocardial / Q000379:methods*; D007530:Isoflurane / Q000494:pharmacology; D008297:Male; D008928:Mitochondria / Q000187:drug effects* / Q000201:enzymology / Q000378:metabolism; D015428:Myocardial Reperfusion Injury / Q000378:metabolism / Q000503:physiopathology; D009206:Myocardium / Q000378:metabolism; D009566:Nitrates / Q000378:metabolism; D019001:Nitric Oxide Synthase / Q000037:antagonists & inhibitors; D009573:Nitrites / Q000378:metabolism; D015221:Potassium Channels / Q000187:drug effects; D011897:Random Allocation; D051381:Rats; D017207:Rats, Sprague-Dawley; D017382:Reactive Oxygen Species / Q000378:metabolism; D013482:Superoxide Dismutase / Q000378:metabolism*; D013481:Superoxides / Q000378:metabolism
chemical_list: D000777:Anesthetics; D003652:Decanoic Acids; D006880:Hydroxy Acids; D009566:Nitrates; D009573:Nitrites; D015221:Potassium Channels; D017382:Reactive Oxygen Species; C117780:mitochondrial K(ATP) channel; D013481:Superoxides; C052853:5-hydroxydecanoic acid; D000255:Adenosine Triphosphate; D007530:Isoflurane; D019001:Nitric Oxide Synthase; D013482:Superoxide Dismutase