title: Role of iNOS and peroxynitrite-matrix metalloproteinase-2 signaling in myocardial late preconditioning in rats.
abstract: We have previously shown that the inhibition of myocardial nitric oxide (NO) and peroxynitrite-matrix metalloproteinase (MMP) signaling by early preconditioning (PC) is involved in its cardioprotective effect. Therefore, in the present study, we investigated the role of NO and peroxynitrite-MMP signaling in the development of late PC. PC was performed by five consecutive cycles of 4-min coronary occlusion and 4-min reperfusion in anesthetized rats in vivo. Twenty-four hours later, hearts were subjected to a 30-min coronary occlusion followed by 180-min reperfusion to measure infarct size. In separate experiments, heart tissue was sampled to measure biochemical parameters before and 3, 6, 12, or 24 h after the PC protocol, respectively. Late PC decreased infarct size, increased cardiac inducible NO synthase (iNOS) activity and gene expression, and decreased SOD activity at 24 h significantly compared with sham-operated controls. Late PC increased cardiac superoxide levels significantly at 24 h; however, it did not change cardiac NO levels. Cardiac peroxynitrite levels were significantly decreased. Downstream cellular targets of peroxynitrite, MMP-2 and MMP-9 activities were decreased in the late PC group at 24 h compared with the sham-operated group. To verify if PC-induced inhibition of MMPs had a causative role in the reduction of infarct size, in separate experiments, we measured infarct size after the pharmacological inhibition of MMPs by ilomastat and found a significant reduction of infarct size compared with the vehicle-treated group. In conclusion, this is the first demonstration that the inhibition of cardiac peroxynitrite-MMP signaling contributes to cardioprotection by late PC and that pharmacological inhibition of MMPs is able to reduce infarct size in vivo. Furthermore, increased expression of iNOS may play a role in the development of late PC; however, increased iNOS activity does not lead to increased NO production in late PC.
authors.affiliation: Cardiovascular Research Group, Dept. of Biochemistry, Univ. of Szeged, Dóm tér 9, Szeged H-6720, Hungary. peter.ferdinandy@pharmahungary.com
authors.forename: Péter
authors.initials: P
authors.lastname: Bencsik
authors.forename: Krisztina
authors.initials: K
authors.lastname: Kupai
authors.forename: Zoltán
authors.initials: Z
authors.lastname: Giricz
authors.forename: Anikó
authors.initials: A
authors.lastname: Görbe
authors.forename: Judit
authors.initials: J
authors.lastname: Pipis
authors.forename: Zsolt
authors.initials: Z
authors.lastname: Murlasits
authors.forename: Gabriella F
authors.initials: GF
authors.lastname: Kocsis
authors.forename: Zoltán
authors.initials: Z
authors.lastname: Varga-Orvos
authors.forename: László G
authors.initials: LG
authors.lastname: Puskás
authors.forename: Csaba
authors.initials: C
authors.lastname: Csonka
authors.forename: Tamás
authors.initials: T
authors.lastname: Csont
authors.forename: Péter
authors.initials: P
authors.lastname: Ferdinandy
mesh_terms: D000818:Animals; D004195:Disease Models, Animal; D004789:Enzyme Activation; D006877:Hydroxamic Acids; D007211:Indoles / Q000494:pharmacology; D019157:Ischemic Preconditioning, Myocardial / Q000379:methods*; D008297:Male; D020778:Matrix Metalloproteinase 2 / Q000378:metabolism*; D020780:Matrix Metalloproteinase 9 / Q000378:metabolism; D061965:Matrix Metalloproteinase Inhibitors; D009203:Myocardial Infarction / Q000201:enzymology / Q000473:pathology / Q000517:prevention & control*; D015428:Myocardial Reperfusion Injury / Q000201:enzymology / Q000473:pathology / Q000517:prevention & control*; D009206:Myocardium / Q000201:enzymology* / Q000473:pathology; D009569:Nitric Oxide / Q000378:metabolism; D052247:Nitric Oxide Synthase Type II / Q000235:genetics / Q000378:metabolism*; D030421:Peroxynitrous Acid / Q000378:metabolism*; D011480:Protease Inhibitors / Q000494:pharmacology; D051381:Rats; D017208:Rats, Wistar; D015398:Signal Transduction / Q000187:drug effects; D013482:Superoxide Dismutase / Q000378:metabolism; D013481:Superoxides / Q000378:metabolism; D013997:Time Factors; D015854:Up-Regulation
chemical_list: D006877:Hydroxamic Acids; D007211:Indoles; D061965:Matrix Metalloproteinase Inhibitors; D011480:Protease Inhibitors; D013481:Superoxides; D030421:Peroxynitrous Acid; D009569:Nitric Oxide; D052247:Nitric Oxide Synthase Type II; C496318:Nos2 protein, rat; D013482:Superoxide Dismutase; D020778:Matrix Metalloproteinase 2; C522363:Mmp2 protein, rat; D020780:Matrix Metalloproteinase 9; C119203:ilomastat