scholarly journals Noninvasive Delayed Limb Ischemic Preconditioning Attenuates Myocardial Ischemia-Reperfusion Injury in Rats by a Mitochondrial KATP Channel-Dependent Mechanism

2011 ◽  
pp. 271-279 ◽  
Author(s):  
Y.-N. WU ◽  
H. YU ◽  
X.-H. ZHU ◽  
H.-J. YUAN ◽  
Y. KANG ◽  
...  
Keyword(s):  
Myocardial Ischemia ◽  
Reperfusion Injury ◽  
Ischemic Preconditioning ◽  
Katp Channel ◽  
Ischemia Reperfusion Injury ◽  
Ischemia Reperfusion ◽  
Control Group ◽  
Myocardial Ischemia Reperfusion Injury ◽  
Myocardial Ischemia Reperfusion ◽  
Dependent Mechanism

We previously demonstrated in rats that noninvasive delayed limb ischemic preconditioning (LIPC) induced by three cycles of 5-min occlusion and 5-min reperfusion of the left hind limb per day for three days confers the same cardioprotective effect as local ischemic preconditioning of the heart, but the mechanism has not been studied in depth. The aim of this project was to test the hypothesis that delayed LIPC enhances myocardial antioxidative ability during ischemia-reperfusion by a mitochondrial KATP channel (mito KATP)-dependent mechanism. Rats were randomized to five groups: ischemia-reperfusion (IR)-control group, myocardial ischemic preconditioning (MIPC) group, LIPC group, IR-5HD group and LIPC-5HD group. The MIPC group underwent local ischemic preconditioning induced by three cycles of 5-min occlusion and 5-min reperfusion of the left anterior descending coronary arteries. The LIPC and LIPC-5HD groups underwent LIPC induced by three cycles of 5-min occlusion and 5-min reperfusion of the left hind limb using a modified blood pressure aerocyst per day for three days. All rats were subjected to myocardial ischemia-reperfusion injury. The IR-5HD and LIPC-5HD groups received the mito KATP channel blocker 5-hydroxydecanoate Na (5-HD) before and during the myocardial ischemia-reperfusion injury. Compared with the IR-control group, both the LIPC and MIPC groups showed an amelioration of ventricular arrhythmia, reduced myocardial infarct size, increased activities of total superoxide dismutase, manganese-superoxide dismutase (Mn-SOD) and glutathione peroxidase, increased expression of Mn-SOD mRNA and decreased xanthine oxidase activity and malondialdehyde concentration. These beneficial effects of LIPC were prevented by 5-HD. In conclusion, delayed LIPC offers similar cardioprotection as local IPC. These results support the hypothesis that the activation of mito KATP channels enhances myocardial antioxidative ability during ischemia-reperfusion, thereby contributing, at least in part, to the anti-arrhythmic and anti-infarct effects of delayed LIPC.

scholarly journals Effects of Thyroid Hormone Analogue and a Leukotrienes Pathway-Blocker on Reperfusion Injury Attenuation after Heart Transplantation

2013 ◽  
Vol 2013 ◽  
pp. 1-8
Author(s):  
Fadhil G. Al-Amran ◽  
Najah R. Hadi ◽  
Haider S. H. Al-Qassam
Keyword(s):  
Myocardial Ischemia ◽  
Heart Transplantation ◽  
Reperfusion Injury ◽  
Ischemia Reperfusion Injury ◽  
Ischemia Reperfusion ◽  
Treated Group ◽  
Control Group ◽  
Group I ◽  
Myocardial Ischemia Reperfusion Injury ◽  
Myocardial Ischemia Reperfusion

Background. Global myocardial ischemia reperfusion injury after heart transplantation is believed to impair graft function and aggravate both acute and chronic rejection episodes. Objectives. To assess the possible protective potential of MK-886 and 3,5-diiodothyropropionic acid DITPA against global myocardial ischemia reperfusion injury after heart transplantation. Materials and Methods. Adult albino rats were randomized into 6 groups as follows: group I sham group; group II, control group; groups III and IV, control vehicles (1,2); group V, MK-886 treated group. Donor rats received MK-886 30 min before transplantation, and the same dose was repeated for recipients upon reperfusion; in group VI, DITPA treated group, donors and recipients rats were pretreated with DITPA for 7 days before transplantation. Results. Both MK-886 and DITPA significantly counteract the increase in the levels of cardiac TNF-α, IL-1β, and ICAM-1 and plasma level of cTnI (). Morphologic analysis showed that both MK-886 and DITPA markedly improved () the severity of cardiac injury in the heterotopically transplanted rats. Conclusions. The results of our study reveal that both MK-886 and DITPA may ameliorate global myocardial ischemia reperfusion injury after heart transplantation via interfering with inflammatory pathway.

Abstract 1000: Dichotomous Roles Of TNF-α Receptors p55 And p75 In Acute Ischemia/reperfusion Injury And Late Ischemic Preconditioning

Circulation ◽  
2007 ◽  
Vol 116 (suppl_16) ◽  
Author(s):  
Michael P Flaherty ◽  
Yiru Guo ◽  
Xian-Liang Tang ◽  
Sumit Tiwari ◽  
Greg Hunt ◽  
...  
Keyword(s):  
Myocardial Ischemia ◽  
Infarct Size ◽  
Reperfusion Injury ◽  
Ischemic Preconditioning ◽  
Coronary Occlusion ◽  
Ischemia Reperfusion Injury ◽  
Ischemia Reperfusion ◽  
Acute Myocardial Ischemia ◽  
Myocardial Ischemia Reperfusion Injury ◽  
Myocardial Ischemia Reperfusion

We have previously demonstrated that TNF-alpha signaling is critical for the development of protection afforded by the late phase of ischemic preconditioning (PC). In the current study, we investigated the roles of p55 (TNFR-I) and p75 (TNFR-II) in acute myocardial ischemia/reperfusion injury as well as late PC. Wild-type (WT, B6 and B6,129 strains), TNF-a−/−, p55−/−, p75−/−, and p55−/−/p75−/− double-knockout mice underwent a 30-min coronary occlusion followed by 4 h of reperfusion with or without six cycles of coronary occlusion/reperfusion (O/R) 24 h earlier. Six cycles of O/R reduced infarct size 24 h later in B6 as well as B6,129 WT mice, indicating a rob ust late PC effect (Figure ). This infarct-sparing effect of late PC was abolished in the absence of TNF-a, p55, p75, and both p55/p75, indicating that TNF-a signaling is critical for the development of late PC protection; and that signaling via both p55 and p75 is necessary for the development of protection. In nonpreconditioned TNF-a−/− and p75−/− mice, infarct size was similar to that observed in strain-matched WT mice (Figure ). However, infarct size in nonpreconditioned p55−/− mice was reduced compared with nonpreconditioned WT mice (46.8 ± 2.8% vs. 63.4 ± 3.2%, P < 0.05, Figure ). These observations were confirmed via linear regression analysis of myocardial risk region and infarct size. We conclude that nonredundant TNF-a signaling via both p55 and p75 is crucial for the development of late PC protection. However, the reduction in infarct size in naïve p55−/− mice indicates a deleterious role of this receptor during acute myocardial ischemia/reperfusion injury.

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