title: Hydrogen peroxide causes cardiac dysfunction independent from its effects on matrix metalloproteinase-2 activation.
abstract: Hydrogen peroxide (H2O2) causes cardiac dysfunction through multiple mechanisms. As oxidative stress can activate matrix metalloproteinases (MMPs) and, in particular, MMP-2 activity is associated with oxidative stress injury in the heart, we hypothesized that MMP-2 activation by H2O2 in isolated rat hearts contributes to cardiac dysfunction in this model. Isolated working rat hearts were perfused at 37 degrees C with a recirculating Krebs-Henseleit buffer+/-5 mmol/L pyruvate, known to protect hearts from oxidative stress. H2O2 (300 micromol/L) was added as a single bolus after 20 min of equilibration, and cardiac function was monitored for 60 min. MMPs activities in both the heart and perfusate samples were assessed by gelatin zymography. Tissue high energy phosphates were analysed by HPLC. The actions of 2 MMP inhibitors, doxycycline (75 micromol/L) or Ro 31-9790 (3 micromol/L), were also assessed. H2O2 at 300 micromol/L produced a rapid decline in cardiac mechanical function, which was maximal at 5 min. A peak in perfusate MMP-2 activity was also observed at 5 min. The deleterious effect of H2O2 on cardiac function was abolished by pyruvate but not by the MMPs inhibitors. This study suggests that in intact hearts, H2O2 induces contractile dysfunction independent of MMPs activation.
authors.affiliation: Department of Pediatrics, Cardiovascular Research Group, 4-62 Heritage Medical Research Centre, University of Alberta, Edmonton, AB T6G 2S2, Canada.
authors.forename: Hernando
authors.initials: H
authors.lastname: León
authors.forename: Norma
authors.initials: N
authors.lastname: Bautista-López
authors.forename: Jolanta
authors.initials: J
authors.lastname: Sawicka
authors.forename: Richard
authors.initials: R
authors.lastname: Schulz
mesh_terms: D000818:Animals; D000975:Antioxidants / Q000494:pharmacology; D003326:Coronary Circulation / Q000187:drug effects; D004318:Doxycycline / Q000494:pharmacology; D006321:Heart / Q000187:drug effects* / Q000502:physiology / Q000503:physiopathology; D006861:Hydrogen Peroxide / Q000633:toxicity*; D006877:Hydroxamic Acids / Q000494:pharmacology; D066298:In Vitro Techniques; D008297:Male; D020778:Matrix Metalloproteinase 2 / Q000378:metabolism*; D061965:Matrix Metalloproteinase Inhibitors; D010710:Phosphates / Q000378:metabolism; D019289:Pyruvic Acid / Q000494:pharmacology; D051381:Rats; D017207:Rats, Sprague-Dawley
chemical_list: D000975:Antioxidants; D006877:Hydroxamic Acids; D061965:Matrix Metalloproteinase Inhibitors; D010710:Phosphates; C097661:Ro 31-9790; D019289:Pyruvic Acid; D006861:Hydrogen Peroxide; D020778:Matrix Metalloproteinase 2; C522363:Mmp2 protein, rat; D004318:Doxycycline