title: Proteomics of ischemia and reperfusion injuries in rabbit myocardium with and without intervention by an oxygen-free radical scavenger.
abstract: A brief period of ischemia followed by timely reperfusion may lead to prolonged, yet reversible, contractile dysfunction (myocardial stunning). Damage to the myocardium occurs not only during ischemia, but also during reperfusion, where a massive release of oxygen-free radicals (OFR) occurs. We have previously utilized 2-DE and MS to define 57 protein spot changes during brief ischemia/reperfusion (15 min ischemia, 60 min reperfusion; 15I/60R) injury in a rabbit model (White, M. Y., Cordwell, S. J., McCarron, H. C. K., Prasan, A. M. et al., Proteomics 2005, 5, 1395-1410) and shown that the majority of these occur because of physical and/or chemical PTMs. In this study, we subjected rabbit myocardium to 15I/60R in the presence of the OFR scavenger N-(2-mercaptopropionyl) glycine (MPG). Thirty-seven of 57 protein spots altered during 15I/60R remained at control levels in the presence of MPG (15I/60R + MPG). Changes to contractile proteins, including myosin light chain 2 (MLC-2) and troponin C (TnC), were prevented by the addition of MPG. To further investigate the individual effects of ischemia and reperfusion, we generated 2-DE gels from rabbit myocardium subjected to brief ischemia alone (15I/0R), and observed alterations of 33 protein spots, including 18/20 seen in both 15I/60R-treated and 15I/60R + MPG-treated tissue. The tissue was also subjected to ischemia in the presence of MPG (15I/0R + MPG), and 21 spot changes, representing 14 protein variants, remained altered despite the presence of the OFR scavenger. These ischemia-specific proteins comprised those involved in energy metabolism (lactate dehydrogenase and ATP synthase alpha), redox regulation (NADH ubiquinone oxidoreductase 51 kDa and GST Mu), and stress response (Hsp27 and 70, and deamidated alpha B-crystallin). We conclude that contractile dysfunction associated with myocardial stunning is predominantly caused by OFR damage at the onset of reperfusion, but that OFR-independent damage also occurs during ischemia. These ischemia-specific protein modifications may be indicative of early myocardial injury.
authors.affiliation: Department of Medicine, The University of Sydney, Sydney, Australia.
authors.forename: Melanie Y
authors.initials: MY
authors.lastname: White
authors.forename: Adrian S
authors.initials: AS
authors.lastname: Tchen
authors.forename: Hugh C K
authors.initials: HC
authors.lastname: McCarron
authors.forename: Brett D
authors.initials: BD
authors.lastname: Hambly
authors.forename: Richmond W
authors.initials: RW
authors.lastname: Jeremy
authors.forename: Stuart J
authors.initials: SJ
authors.lastname: Cordwell
mesh_terms: D000818:Animals; D004734:Energy Metabolism / Q000235:genetics; D016166:Free Radical Scavengers / Q000494:pharmacology*; D005998:Glycine / Q000031:analogs & derivatives / Q000494:pharmacology; D006321:Heart / Q000187:drug effects; D008297:Male; D009124:Muscle Proteins / Q000378:metabolism*; D017682:Myocardial Stunning / Q000235:genetics* / Q000378:metabolism; D009206:Myocardium / Q000378:metabolism*; D010084:Oxidation-Reduction; D040901:Proteomics; D011817:Rabbits; D017382:Reactive Oxygen Species / Q000378:metabolism; D015427:Reperfusion Injury / Q000235:genetics*; D013438:Sulfhydryl Compounds / Q000494:pharmacology
chemical_list: D016166:Free Radical Scavengers; D009124:Muscle Proteins; C110658:N-(2-mercaptoproprionyl)-glycine; D017382:Reactive Oxygen Species; D013438:Sulfhydryl Compounds; D005998:Glycine