史春霞
中国医学科学院阜外医院 麻醉科
BACKGROUND:Studies suggested that anesthetics administered upon the early reperfusion or "anesthetic postconditioning" could protect post-ischemic hearts against myocardial ischemia reperfusion injury (MIRI). However, the mechanism responsible for such protection was not well-elucidated. We investigated the cardioprotection induced by sevoflurane postconditioning (SpostC) in rat hearts in vitro, and the respective role of phosphatidylinositol-3-kinase (PI3K), extracellular signal-regulated kinase 1 and 2 (ERK 1/2), mitochondrial K(ATP) channels (mitoK(ATP)) and mitochondrial permeability transition pore (mPTP), by selectively inhibiting PI3K, ERK 1/2, mitoK(ATP), with LY294002 (LY), PD98059 (PD), 5-hydroxydecanoate (5-HD) and by directly opening of mPTP with atractyloside (ATR), respectively.METHODS:Isolated rat hearts were randomly assigned to one of the 12 groups (n = 15): Time control (continuous perfusion), ISCH (30 minutes of ischemia followed by 60 minutes of reperfusion alone), SpostC (3% sevoflurane postconditioning was administered during the first 15 minutes of reperfusion after 30 minutes of ischemia), ISCH + LY, ISCH + PD, ISCH + ATR, ISCH + 5-HD and ISCH + dimethyl sulfoxide (DMSO) groups (LY, PD, ATR, 5-HD and DMSO (the vehicle) was administered respectively during the first 15 minutes of reperfusion following test ischemia), SpostC + LY, SpostC + PD, SpostC + ATR and SpostC + 5-HD groups (LY, PD, ATR and 5-HD was coadministered with 3% sevoflurane, respectively). Hemodynamics was compared within and between groups. Infarction size was determined at the end of experiments using triphenyltetrazolium chloride (TTC) staining. Lactate dehydrogenase (LDH), creatine kinase-MB (CK-MB) and cardiac troponin I (cTnI) released from necrotic myocardium, were compared among TC, ISCH and SpostC groups. To investigate the relationships between RISK and mPTP implicated in SpostC, NAD(+) content in myocardium, a marker of mPTP opening, was compared among some experimental groups (TC, ISCH, ISCH + LY, ISCH + PD, ISCH + DMSO, SpostC, SpostC + LY, SpostC + PD). To further investigate whether the anti-apoptotic mechanism is implicated in SpostC-induced cardioprotection and its association with mitochondria, TUNEL staining was performed in some experimental groups (TC, ISCH, ISCH + 5-HD, ISCH + ATR, ISCH + DMSO, SpostC, SpostC + 5-HD, SpostC + ATR).RESULTS:When compared with unprotected hearts subjected to 30 minutes of ischemia, exposure to 3% sevoflurane for 15 minutes during early reperfusion significantly improved functional recovery, decreased myocardial infarct size, decreased LDH, CK-MB and cTnI release, and decreased cardiomyocyte apoptosis (P < 0.05). However, such cardioprotective effects of hemodynamic recovery and infarct size reduction by sevoflurane was completely abolished by any one of LY294002, PD98059, atractyloside and 5-hydroxydecanoate (P < 0.05). Additionally, either LY294002 or PD98059 could reverse the inhibitory effect of SpostC over mPTP opening upon reperfusion (P < 0.05). Both atractyloside and 5-hydroxydecanoate could abrogate the anti-apoptotic effects of SpostC (P < 0.05).CONCLUSION:These findings demonstrate that PI3K, ERK 1/2, mitoK(ATP) and mPTP are key players in sevoflurane postconditioning induced cardioprotective mechanisms in isolated rat hearts subjected to MIRI.
Chinese medical journal 2010
Volatile anesthetic ischemic postconditioning reduces infarct size following ischemia/reperfusion. Whether phosphorylation of protein kinase B (PKB/Akt) and glycogen synthase kinase 3 beta (GSK3β) is causal for cardioprotection by postconditioning is controversial. We therefore investigated the impact of PKB/Akt and GSK3β in isolated perfused rat hearts subjected to 40 min of ischemia followed by 1 h of reperfusion. 2.0% sevoflurane (1.0 minimum alveolar concentration) was administered at the onset of reperfusion in 15 min as postconditioning. Western blot analysis was used to determine phosphorylation of PKB/Akt and its downstream target GSK3β after 1 h of reperfusion. Mitochondrial and cytosolic content of cytochrome C checked by western blot served as a marker for mitochondrial permeability transition pore opening. Sevoflurane postconditioning significantly improved functional cardiac recovery and decreased infarct size in isolated rat hearts. Compared with unprotected hearts, sevoflurane postconditioning-induced phosphorylation of PKB/Akt and GSK3β were significantly increased. Increase of cytochrome C in mitochondria and decrease of it in cytosol is significant when compared with unprotected ones which have reversal effects on cytochrome C. The current study presents evidence that sevoflurane-induced cardioprotection at the onset of reperfusion are partly through activation of PKB/Akt and GSK3β.
Molecular biology reports 2010
We evaluated the cardioprotection against myocardial ischemia-reperfusion injury induced by sevoflurane postconditioning (SpostC) in chronically-infarcted rat hearts, and investigated the roles of phosphoinositide 3-kinase (PI3K)-protein kinase B/Akt (PKB/Akt), mitogen-activated extracellular regulated kinase 1/2 (MEK 1/2)-extracellular regulated kinase 1/2 (ERK 1/2), and mitochondrial permeability transition pore (mPTP). Left anterior descending (LAD) coronary artery was ligated to induce myocardial infarction in rats. Six weeks later, chronically-infarcted hearts were isolated and subjected to 30 min of global ischemia, followed by 1 h of reperfusion with Krebs-Henseleit (K-H) buffer. SpostC was administered by perfusing the hearts with K-H buffer saturated with 3% sevoflurane during the first 15 min of reperfusion. To evaluate the role of PI3K-PKB/Akt and MEK 1/2-ERK 1/2 in SpostC, PI3K inhibitor LY294002 (15 microM) and MEK 1/2 inhibitor PD98059 (20 microM) were administered alone or together with sevoflurane during the first 15 min of reperfusion. We found that exposure of 3% sevoflurane during early reperfusion significantly improved functional recovery (improved left ventricular developed pressure (LVDP), +/-dp/dt, CF, HR and reduced left ventricular end-diastolic pressure (LVEDP)), decreased myocardial infarct size and reduced LDH and CK-MB release, when compared with unprotected hearts. However, these protective effects were abolished in the presence of either LY294002 or PD98059, which was accompanied by the prevention of PKB/Akt and ERK 1/2 phosphorylation, and reduction of myocardial nicotinamide adenine dinucleotide (NAD+) content. These findings suggest that sevoflurane postconditioning protects chronically-infarcted rat hearts against ischemia-reperfusion injury by inhibiting mPTP opening via recruitment of PKB/Akt and ERK 1/2.
Biological & pharmaceutical bulletin 2009
