title: Enhanced ADP-ribosylation and its diminution by lipoamide after ischemia-reperfusion in perfused rat heart.
abstract: Poly-ADP-ribose polymerase (PARP) is considered to play an important role in oxidative cell damage. We assumed that ischemia-reperfusion resulting from the increasing reactive oxygen species (ROS) can lead to the activation of endogenous mono- and poly-ADP-ribosylation reactions and that the reduction of ROS level by lipoamide, a less known antioxidant, can reverse these unfavorable processes. Experiments were performed on isolated Langendorff hearts subjected to 60-min ischemia followed by reperfusion. ROS, malondialdehyde, deoxyribonucleic acid (DNA) breaks, and NAD+ content were assayed in the hearts, and the ADP-ribosylation of cytoplasmic and nuclear proteins were determined by Western blot assay. Ischemia-reperfusion caused a moderate (30.2 +/- 8%) increase in ROS production determined by the dihydrorhodamine 123 method and significantly increased the malondialdehyde production (from < 1 to 23 +/- 2.7 nmol/ml), DNA damage (undamaged DNA decreased from 71 +/- 7% to 23.1 +/- 5%), and NAD+ catabolism. In addition, ischemia-reperfusion activated the mono-ADP-ribosylation of GRP78 and the self-ADP-ribosylation of the nuclear PARP. The perfusion of hearts with lipoamide significantly decreased the ischemia-reperfusion-induced cell membrane damage determined by enzyme release (LDH, CK, and GOT), decreased the ROS production, reduced the malondialdehyde production to 5.5 +/- 2.4 nmol/ml, abolished DNA damage, and reduced NAD+ catabolism. The ischemia-reperfusion-induced activation of poly- and mono-ADP-ribosylation reactions were also reverted by lipoamide. In isolated rat heart mitochondria, dihydrolipoamide was found to be a better antioxidant than dihydrolipoic acid. Ischemia-reperfusion by ROS overproduction and increasing DNA breaks activates PARP leading to accelerated NAD+ catabolism, impaired energy metabolism, and cell damage. Lipoamide by reducing ROS levels halts PARP activation and membrane damage and improves the recovery of postischemic myocardium.
authors.affiliation: Department of Biochemistry, University Medical School Pecs, Hungary.
authors.forename: E
authors.initials: E
authors.lastname: Szabados
authors.forename: G M
authors.initials: GM
authors.lastname: Fischer
authors.forename: F
authors.initials: F
authors.lastname: Gallyas
authors.forename: G
authors.initials: G
authors.lastname: Kispal
authors.forename: B
authors.initials: B
authors.lastname: Sumegi
mesh_terms: D036002:ADP Ribose Transferases; D000246:Adenosine Diphosphate Ribose / Q000378:metabolism*; D000818:Animals; D000975:Antioxidants / Q000494:pharmacology*; D004249:DNA Damage; D004789:Enzyme Activation / Q000187:drug effects; D066298:In Vitro Techniques; D015227:Lipid Peroxidation / Q000187:drug effects; D008297:Male; D008929:Mitochondria, Heart / Q000187:drug effects / Q000378:metabolism; D015428:Myocardial Reperfusion Injury / Q000188:drug therapy* / Q000378:metabolism*; D009243:NAD / Q000378:metabolism; D010477:Perfusion; D011065:Poly(ADP-ribose) Polymerases / Q000378:metabolism; D011506:Proteins / Q000378:metabolism; D051381:Rats; D017208:Rats, Wistar; D017382:Reactive Oxygen Species / Q000378:metabolism; D008063:Thioctic Acid / Q000031:analogs & derivatives* / Q000494:pharmacology
chemical_list: D000975:Antioxidants; D011506:Proteins; D017382:Reactive Oxygen Species; D009243:NAD; D000246:Adenosine Diphosphate Ribose; C007409:dihydrolipoamide; D008063:Thioctic Acid; C015144:dihydrolipoic acid; C013091:lipoamide; D036002:ADP Ribose Transferases; D011065:Poly(ADP-ribose) Polymerases