Role of 4-hydroxynonenal in modification of cytochrome c oxidase in ischemia/reperfused rat heart.
Mitochondrial dysfunction is a characteristic of ischemia/reperfusion (I/R) injury in the heart. While oxidative stress has been implicated in mitochondrial damage in I/R injury, the underlying mechanisms are unclear. 4-Hydroxynonenal (HNE) is a toxic aldehyde generated by lipid peroxidation. The purpose of the present study was to assess the role of HNE in I/R-induced damage of a crucial component of the mitochondrial electron transport chain, cytochrome c oxidase (COX). I/R was induced in male WKY rats by 15 mins of ischemia followed by reperfusion for up to 3 h. COX activity was measured spectrophotometrically at 550 nm. HNE adducts with COX subunits were detected by Western Blot using an HNE-histidine antibody. HNE and reduced glutathione (GSH) contents were measured in mitochondria by HPLC. Following 3 h of reperfusion, COX activity was reduced to 59% of control, accompanied by increases in HNE adducts with COX (P<0.05). Mitochondrial HNE content in reperfused hearts was increased to 165% of control, whereas GSH was decreased to 62% of control (P<0.05). After purified COX was incubated with HNE in vitro, COX activity was decreased progressively with increasing concentrations of HNE, accompanied by concentration-dependent formation of HNE adducts with COX. GSH prevented HNE adduct formation as well as COX inhibition by HNE. These results suggest that HNE, via adduct formation with COX subunits, plays an important role in COX dysfunction caused by reperfusion. The findings also indicate that decreases in mitochondrial GSH stores in reperfused myocardium could potentiate HNE-mediated COX damage.
Chen
J
J
The Department of Medicine, Division of Gastroenterology and Nutrition, San Antonio, Texas 78284, USA. chenjl@uthscsa.edu
Henderson
G I
GI
Freeman
G L
GL
D000447:Aldehydes / Q000494:pharmacology*; D000818:Animals; D015153:Blotting, Western; D002851:Chromatography, High Pressure Liquid; D015853:Cysteine Proteinase Inhibitors / Q000494:pharmacology*; D004305:Dose-Response Relationship, Drug; D003576:Electron Transport Complex IV / Q000737:chemistry* / Q000378:metabolism / Q000502:physiology*; D005978:Glutathione / Q000378:metabolism; D006131:Growth Inhibitors / Q000494:pharmacology*; D008297:Male; D017202:Myocardial Ischemia / Q000378:metabolism; D015425:Myocardial Reperfusion; D009206:Myocardium / Q000201:enzymology / Q000378:metabolism*; D018384:Oxidative Stress; D051381:Rats; D011921:Rats, Inbred WKY; D015427:Reperfusion Injury / Q000378:metabolism; D013997:Time Factors
D000447:Aldehydes; D015853:Cysteine Proteinase Inhibitors; D006131:Growth Inhibitors; D003576:Electron Transport Complex IV; D005978:Glutathione; C027576:4-hydroxy-2-nonenal