Role of endogenous testosterone in myocardial proinflammatory and proapoptotic signaling after acute ischemia-reperfusion

2005 ◽  
Vol 288 (1) ◽  
pp. H221-H226 ◽  
Author(s):  
Meijing Wang ◽  
Ben M. Tsai ◽  
Ajay Kher ◽  
Lauren B. Baker ◽  
G. Mathenge Wairiuko ◽  
...  
Keyword(s):  
P38 Mapk ◽  
Functional Recovery ◽  
Caspase 3 ◽  
Diastolic Pressure ◽  
Contractile Function ◽  
Ischemia Reperfusion ◽  
Left Ventricular ◽  
Acute Ischemia ◽  
Caspase 1 ◽  
Tnf Α

Myocardial ischemia is the leading cause of death in both men and women; however, very little information exists regarding the effect of testosterone on the response of myocardium to acute ischemic injury. We hypothesized that testosterone may exert deleterious effects on myocardial inflammatory cytokine production, p38 MAPK activation, apoptotic signaling, and myocardial functional recovery after acute ischemia-reperfusion (I/R). To study this, isolated, perfused rat hearts (Langendorff) from adult males, castrated males, and males treated with a testosterone receptor blocker (flutamide) were subjected to 25 min of ischemia followed by 40 min of reperfusion. Myocardial contractile function (left ventricular developed pressure, left ventricular end-diastolic pressure, positive and negative first derivative of pressure) was continuously recorded. After reperfusion, hearts were analyzed for expression of tissue TNF-α, IL-1β, and IL-6 (ELISA) and activation of p38 MAPK, caspase-1, caspase-3, caspase-11, and Bcl-2 (Western blot). All indices of postischemic myocardial functional recovery were significantly higher in castrated males or flutamide-treated males compared with untreated males. After I/R, castrated male and flutamide-treated male hearts had decreased TNF-α, IL-1β, and IL-6; decreased activated p38 MAPK; decreased caspase-1, caspase-3, and caspase-11; and increased Bcl-2 expression compared with untreated males. These results show that blocking the testosterone receptor (flutamide) or depleting testosterone (castration) in normal males improves myocardial function after I/R. These effects may be attributed to the proinflammatory and/or the proapoptotic properties of endogenous testosterone. Further understanding may allow therapeutic manipulation of sex hormone signaling mechanisms in the treatment of acute I/R.

Sex differences in the myocardial inflammatory response to ischemia-reperfusion injury

2005 ◽  
Vol 288 (2) ◽  
pp. E321-E326 ◽  
Author(s):  
Meijing Wang ◽  
Lauren Baker ◽  
Ben M. Tsai ◽  
Kirstan K. Meldrum ◽  
Daniel R. Meldrum
Keyword(s):  
Sex Differences ◽  
Inflammatory Response ◽  
P38 Mapk ◽  
Myocardial Function ◽  
Contractile Function ◽  
Ischemia Reperfusion ◽  
Mapk Signaling ◽  
Left Ventricular ◽  
Rt Pcr ◽  
Tnf Α

The myocardium generates inflammatory mediators during ischemia-reperfusion (I/R), and these mediators contribute to cardiac functional depression and apoptosis. The great majority of these data have been derived from male animals and humans. Sex has a profound effect over many inflammatory responses; however, it is unknown whether sex affects the cardiac inflammatory response to acute myocardial I/R. We hypothesized the existence of inherent sex differences in myocardial function, expression of inflammatory cytokines, and activation of the p38 mitogen-activated protein kinase (MAPK) signaling pathway after I/R. Isolated rat hearts from age-matched adult males and females were perfused (Langendorff), and myocardial contractile function was continuously recorded. After I/R, myocardium was assessed for expression of TNF-α, IL-1β, and IL-6 (RT-PCR, ELISA); IL-1α and IL-10 mRNA (RT-PCR); and activation of p38 MAPK (Western blot). All indexes of postischemic myocardial function [left ventricular developed pressure, left ventricular end-diastolic pressure, and maximal positive (+dP/d t) and negative (−dP/d t) values of the first derivative of pressure] were significantly improved in females compared with males. Compared with males, females had decreased myocardial TNF-α, IL-1β, and IL-6 (mRNA, protein) and decreased activation of p38 MAPK pathway. These data demonstrate that hearts from age-matched adult females are relatively protected against I/R injury, possibly due to a diminished inflammatory response.

Estrogen receptor-α mediates acute myocardial protection in females

2006 ◽  
Vol 290 (6) ◽  
pp. H2204-H2209 ◽  
Author(s):  
Meijing Wang ◽  
Paul Crisostomo ◽  
George M. Wairiuko ◽  
Daniel R. Meldrum
Keyword(s):  
Estrogen Receptor ◽  
Sex Differences ◽  
Functional Recovery ◽  
Contractile Function ◽  
Ischemia Reperfusion ◽  
Analysis Data ◽  
Estrogen Receptor Α ◽  
Left Ventricular ◽  
Acute Ischemia ◽  
Ischemia And Reperfusion Injury

Sex differences in myocardial recovery have been reported after acute ischemia and reperfusion injury. Estrogen and the estrogen receptor are critical determinants of cardiovascular sex differences. However, the mechanistic pathways responsible for these differences remain unknown. We hypothesized that estrogen receptor-α is an important modulator of 1) myocardial functional recovery after ischemia and 2) inflammatory signaling via MAPK. To study this, adult male and female wild-type (WT) and estrogen receptor-α knockout (ER1KO) mouse hearts were isolated, perfused via Langendorff model, and subjected to 20 min of ischemia and 60 min of reperfusion. Myocardial contractile function (left ventricular developed pressure and positive and negative first derivative of pressure) was continuously recorded. After ischemia-reperfusion, hearts were assessed for expression of inflammatory cytokines (ELISA) and activation of MAPK and caspase-3 (Western blot analysis). Data were analyzed with two-way ANOVA or Student's t-test, and P < 0.05 was statistically significant. ER1KO females exhibited significantly less functional recovery than WT females and were similar to WT males. Activated ERK was increased in female WT hearts compared with female ER1KO. Activated JNK was decreased in female WT hearts compared with female ER1KO. No significant differences were found between male WT, female WT, male ER1KO, and female ER1KO in activated p38 MAPK, proinflammatory cytokine expression, and proapoptotic signaling. Estrogen receptor-α plays a role in the protection observed in the female heart. Differential activation of MAPK may mediate this protection. Further studies are necessary to delineate these mechanistic pathways.

Paricalcitol pretreatment attenuates renal ischemia/reperfusion injury by inhibiting p38 MAPK and activating PI3K/Akt signaling pathways

2019 ◽  
Vol 44 (4) ◽  
pp. 452-461
Author(s):  
Zahide Cavdar ◽  
Cemre Ural ◽  
Ayse Kocak ◽  
Sevki Arslan ◽  
Sibel Ersan ◽  
...  
Keyword(s):  
Signaling Pathways ◽  
P38 Mapk ◽  
Caspase 3 ◽  
Ischemia Reperfusion ◽  
Akt Signaling ◽  
Albino Rats ◽  
Sod Activity ◽  
Interstitial Inflammation ◽  
Tnf Α ◽  
Active Caspase

Abstract Objective This study aimed to investigate the renoprotective effects of paricalcitol, a synhetic vitamin D analog, through its possible roles on p38 MAPK and PI3K/Akt signaling pathways to prevent oxidative stress, inflammation and apoptosis during renal I/R. Materials and methods Total 20 kidney tissues of sham (n = 6), subjected to renal I/R bilaterally for 45 min ischemia followed by 24 h reperfusion (n = 7) and paricalcitol (0.3 μg/kg, ip) pretreated Wistar albino rats (n =7) were used in this study. Interstitial inflammation and active caspase-3 expression were evaluated histologically. TNF-α, IL-1β, kidney injury molecule-1 (KIM-1), MDA and SOD activity in kidneys were analysed biochemically. Furthermore, activation of p38 MAPK, PI3K/Akt signaling pathways and NFκB p65 were evaluated by western blot. Results Paricalcitol pretreatment significantly reduced interstitial inflammation during renal I/R, which was consistent with decreased tumor TNF-α, IL-1β, active caspase-3 and KIM-1 expression. Paricalcitol also reduced MDA level and attenuated the reduction of SOD activity in the kidney during I/R. Moreover, paricalcitol could suppress the p38 MAPK and NFκB p65, and also activate PI3K/Akt signaling pathway during renal I/R. Conclusion All these findings indicate that paricalcitol may be an effective practical strategy to prevent renal I/R injury.

scholarly journals P1: CHOLINERGIC RECEPTOR FUNCTION IN CARDIAC ISCHEMIC PRECONDITIONING

2016 ◽  
Vol 64 (3) ◽  
pp. 817.2-817
Author(s):  
CW Mullan ◽  
SA Mavropolous ◽  
K Ojamaa
Keyword(s):  
Ischemic Preconditioning ◽  
Diastolic Pressure ◽  
Contractile Function ◽  
Ischemia Reperfusion ◽  
Structural Complexity ◽  
Cholinergic Receptor ◽  
Left Ventricular ◽  
Sprague Dawley ◽  
Inner Mitochondrial Membrane ◽  
Cardiac Contractile Function

Purpose of StudyCardiac acetylcholine (ACh) signaling is protective, but the role of ACh in ischemic preconditioning (IPC) remains largely unknown. We studied the effect of selective alpha-7 nicotinic ACh receptor (a7nAChR) antagonism by methyllycaconitine (MLA) on the functional benefits of IPC and the effects of this on mitochondrial complexity and inner mitochondrial membrane potential (ψM).Methods UsedMale Sprague Dawley rats (n=17, 322±17 g) were heparinized and anesthetized with 80 mg/kg pentobarbital IP, and their hearts excised and perfused at constant pressure with a non-circulating Langendorff apparatus. Left ventricular (LV) pressure (LVDP) and heart rate (HR) were continually measured with a fluid filled latex balloon attached to a pressure transducer. Treatment groups were: ischemia-reperfusion (IR)(n=6): 20 min. perfusion, 30 min. of global ischemia, 45 min. of reperfusion; IPC (n=5): 10 min. perfusion, 3 min. ischemia with 2 min. reperfusion repeated 3 times prior to IR protocol, IPC+MLA (n=6): 6 min. perfusion, 4 min. of infusion of MLA at 233 nM, IPC with MLA during reperfusion periods, then IR. Mitochondria were isolated from the LV free wall, stained for ψM and for size, and examined by Flow Cytometry with a BD LSRFortessa. Controls (C) (n=4) were freshly excised hearts from similar animals with identical anesthesia.Summary of ResultsIPC increased LV work product (LVDP times HR) as a percent of pre-ischemia (%P) during reperfusion compared to IR control, and this effect was attenuated by MLA pretreatment (IR=24.1±4.5%P, IPC=49.8±2.8%P, IPC+MLA=33.8±3.5%P, p<0.01). IPC reduced end diastolic pressure from IR levels, and this was partially prevented by MLA treatment (IR=78.8±7.7 mm Hg, IPC=18.8±6.6 mm Hg, IPC+MLA=46.3±8.6 mm Hg, p<0.05). IPC maintained mitochondrial structural complexity compared to IR (C=65±6% of total mitochondria, IPC=61±5%, IR=32±4%, p<0.01). MLA reduced the effect of IPC on ψM in intact mitochondria to IR levels (IR=67±10% of intact population, IPC=88±3%, IPC+MLA=71±4%, p<0.01).ConclusionsSignaling through the a7nAChR is necessary for the effect of IPC on maintaining ψM and cardiac contractile function after IR injury.

Analyzing the anti-ischemia–reperfusion injury effects of ginsenoside Rb1 mediated through the inhibition of p38α MAPK

2016 ◽  
Vol 94 (1) ◽  
pp. 97-103 ◽  
Author(s):  
Gonghao Li ◽  
Wenhao Qian ◽  
Changyun Zhao
Keyword(s):  
P38 Mapk ◽  
Caspase 3 ◽  
Sham Group ◽  
Ischemia Reperfusion Injury ◽  
Ischemia Reperfusion ◽  
Mitogen Activated Protein Kinase ◽  
Ginsenoside Rb1 ◽  
Group I ◽  
Tnf Α ◽  
P38α Mapk

Recent studies have demonstrated that ginsenoside Rb1 protects the myocardium from ischemia–reperfusion (I/R) injury. However, the precise mechanisms for this protection have not been determined. This study aimed to determine whether the attenuation of I/R-induced myocardial injury by ginsenoside Rb1 (GS Rb1) is due to inhibition of p38α mitogen-activated protein kinase (MAPK). Sprague–Dawley rats were distributed among 6 treatment groups: sham group; I/R group; p38 MAPK inhibitor SB203580 group (SB + I/R); GS Rb1 group (GS + I/R); p38 MAPK agonist anisomycin group (Ani + I/R); and the GS Rb1 + Ani group (GS + Ani + I/R). All of the anaesthetized rats, except those in the sham group, underwent an open-chest procedure that involved 30 min of myocardial ischemia followed by 2 h of reperfusion. Myocardial infarction size (MIS), caspase-3 activity, and levels of the cytokine tumor necrosis factor alpha (TNF-α) in the myocardium were monitored. The expressions of p38α MAPK, caspase-3, and TNF-α in the myocardium were assayed. GS Rb1 reduced MIS and attenuated caspase-3 activity and the levels of TNF-α in the myocardium. Protein expression of total p38α MAPK was not significantly altered. In the Ani + I/R and I/R groups, the levels of phospho-p38α MAPK were significantly increased compared with the sham group, and these increased levels were reduced with GS Rb1. Hemodynamic parameters were not significantly different between the GS + I/R and SB + I/R groups. GS Rb1 exerts an anti-apoptotic effect that protects against I/R injury by inhibiting p38α MAPK phosphorylation, suggesting that GS Rb1-mediated protection requires the inhibition of p38α MAPK.

Insulin-induced myocardial protection in isolated ischemic rat hearts requires p38 MAPK phosphorylation of Hsp27

2008 ◽  
Vol 294 (1) ◽  
pp. H74-H87 ◽  
Author(s):  
Gefeng Li ◽  
Imtiaz S. Ali ◽  
R. William Currie
Keyword(s):  
Heat Shock ◽  
Reperfusion Injury ◽  
P38 Mapk ◽  
Functional Recovery ◽  
Insulin Treatment ◽  
Ischemia Reperfusion Injury ◽  
Contractile Function ◽  
Core Body Temperature ◽  
Ischemia Reperfusion ◽  
Constitutive Expression

Six hours after insulin treatment, hearts express heat shock protein 70 (Hsp70) and have improved contractile function after ischemia-reperfusion injury. In this study we examined hearts 1 h after insulin treatment for contractile function and for expression of Hsp70 and Hsp27. Adult, male Sprague-Dawley rats were assigned to groups: 1) sham, 2) control, 3) insulin injected (200 μU/g body wt), 4) heat shock treated (core body temperature, 42°C for 15 min), and 5) heat shock and insulin treated. At 1 h after these treatments, hearts were isolated, equilibrated to Langendorff perfusion for 30 min, and then subjected for 30 min no-flow global ischemia (37°C) followed by 2 h of reperfusion. Insulin-treated hearts had significantly increased contractile function compared with control hearts. At 1 h after insulin treatment, a minimal change in Hsp70 and Hsp27 content were detected. By 3 h after insulin treatment, a significant increase in Hsp70, but not Hsp27, was detected by Western blot analysis. By immunofluorescence, minimal Hsp70 was detected in insulin-treated hearts, whereas Hsp27 was detected in all hearts, indicative of its constitutive expression. Phosphospecific isoforms of Hsp27 were detected in insulin-, heat shock-, and heat shock and insulin-treated hearts. After ischemia and reperfusion, the insulin-treated hearts had significantly elevated levels of phosphorylated Hsp27. Inhibition of p38 MAPK with SB-203580 blocked the insulin-induced phosphorylation of Hsp27 and the improved functional recovery. In conclusion, insulin induces an apparent rapid phosphorylation of Hsp27 that is associated with improved functional recovery after ischemia-reperfusion injury.

Effects of exercise training on contractile function in myocardial trabeculae after ischemia-reperfusion

2005 ◽  
Vol 99 (1) ◽  
pp. 230-236 ◽  
Author(s):  
Hyosook Hwang ◽  
Peter J. Reiser ◽  
George E. Billman
Keyword(s):  
Exercise Training ◽  
Diastolic Pressure ◽  
Contractile Function ◽  
Isometric Force ◽  
Ischemia Reperfusion ◽  
Left Ventricular ◽  
Aerobic Exercise Training ◽  
Protective Effects ◽  
Shortening Velocity ◽  
Cross Sectional

Potential protective effects of aerobic exercise training on the myocardium, before an ischemic event, are not completely understood. The purpose of the study was to investigate the effects of exercise training on contractile function after ischemia-reperfusion (Langendorff preparation with 15-min global ischemia/30-min reperfusion). Trabeculae were isolated from the left ventricles of both sedentary control and 10- to 12-wk treadmill exercise-trained rats. The maximal normalized isometric force (force/cross-sectional area; Po/CSA) and shortening velocity ( Vo) in isolated, skinned ventricular trabeculae were measured using the slack test. Ischemia-reperfusion induced significant contractile dysfunction in hearts from both sedentary and trained animals; left ventricular developed pressure (LVDP) and maximal rates of pressure development and relaxation (±dP/d tmax) decreased, whereas end-diastolic pressure (EDP) increased. However, this dysfunction (as expressed as percent change from the last 5 min before ischemia) was attenuated in trained myocardium [LVDP: sedentary −60.8 ± 6.4% (32.0 ± 5.5 mmHg) vs. trained −15.6 ± 8.6% (64.9 ± 6.6 mmHg); +dP/d tmax: sedentary −54.1 ± 4.7% (1,058.7 ± 124.2 mmHg/s) vs. trained −16.7 ± 8.4% (1,931.9 ± 188.3 mmHg/s); −dP/d tmax: sedentary −44.4 ± 2.5% (−829.3 ± 52.0 mmHg/s) vs. trained −17.9 ± 7.2% (−1,341.3 ± 142.8 mmHg/s); EDP: sedentary 539.5 ± 147.6%; (41.3 ± 6.0 mmHg) vs. trained 71.6 ± 30.6%; 11.4 ± 1.2 mmHg]. There was an average 26% increase in Po/CSA in trained trabeculae compared with sedentary controls, and this increase was not affected by ischemia-reperfusion. Ischemia-reperfusion reduced V0 by 39% in both control and trained trabeculae. The relative amount of the β-isoform of myosin heavy chain (MHC-β) was twofold greater in trained trabeculae as well as in the ventricular free walls. Despite a possible increase in the economy in the trained heart, presumed from a greater amount of MHC-β, ischemia-reperfusion reduced Vo, to a similar extent in both control and trained animals. Nevertheless, the trained myocardium appears to have a greater maximum force-generating ability that may, at least partially, compensate for reduced contractile function induced by a brief period of ischemia.

Reperfusion at reduced flow rates enhances postischemic contractile recovery of perfused heart

1995 ◽  
Vol 268 (6) ◽  
pp. H2384-H2395 ◽  
Author(s):  
S. Takeo ◽  
J. X. Liu ◽  
K. Tanonaka ◽  
Y. Nasa ◽  
K. Yabe ◽  
...  
Keyword(s):  
Flow Rate ◽  
Diastolic Pressure ◽  
Contractile Function ◽  
Ischemia Reperfusion ◽  
Left Ventricular ◽  
Cardiac Contractile Function ◽  
Triphenyltetrazolium Chloride ◽  
Perfused Heart ◽  
Flow Rates ◽  
Reduced Flow

The effects of reperfusion at reduced flow rates on postischemic cardiac contractile function were examined in perfused rat hearts. Isolated hearts were subjected to 35-min ischemia followed by reperfusion at the preischemic flow rate (9.0 ml.g-1.min-1; ordinary flow rate) or at reduced flow rates (0.9-8.1 ml.g-1.min-1). Reperfusion at ordinary flow rate did not generate any left ventricular developed pressure (LVDP), whereas reperfusion at reduced flow rates (0.9-7.2 ml.g-1.min-1) elicited 13-57% of initial contractile force at reperfusion's end; optimal recovery occurred at 3.6 ml.g-1.min-1 (reduced flow rate). Reduced flow rate reperfusion attenuated ischemia-reperfusion-induced increase in left ventricular end-diastolic pressure (LVEDP) and perfusion pressure (PP), alteration in tissue Na+, K+, Ca2+, and Mg2+, release of creatine kinase and ATP metabolites, and development of triphenyltetrazolium chloride-unstained areas. Enhanced postischemic LVDP recovery was inversely related to higher coronary PP at the initial stage (4 min) of reperfusion (r = -0.763). The benefit of reduced flow rate reperfusion could not be attributed to rate of calcium delivery to the heart, formation of oxygen free radicals in myocardium, endothelium-dependent coronary artery dilation, or LVDEP reduction. Enhancement of postischemic LVDP recovery was associated with attenuation of ischemia-reperfusion-induced increases in myocardial sodium and calcium; failure of postischemic LVDP recovery was accompanied by an increase. Reduction in sodium and calcium overload may underlie the beneficial effects of reduced flow rate reperfusion in ischemic-reperfused heart.

scholarly journals Diabetes Upregulates Oxidative Stress and Downregulates Cardiac Protection to Exacerbate Myocardial Ischemia/Reperfusion Injury in Rats

Antioxidants ◽  
2020 ◽  
Vol 9 (8) ◽  
pp. 679
Author(s):  
Chen-Yen Chien ◽  
Ting-Jui Wen ◽  
Yu-Hsiuan Cheng ◽  
Yi-Ting Tsai ◽  
Chih-Yao Chiang ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Myocardial Ischemia ◽  
Caspase 3 ◽  
Diastolic Pressure ◽  
Myocardial Dysfunction ◽  
Ischemia Reperfusion ◽  
Systolic Pressure ◽  
Left Ventricular ◽  
Microvascular Reactivity ◽  
Myocardial Ischemia Reperfusion

Diabetes exacerbates myocardial ischemia/reperfusion (IR) injury by incompletely understood mechanisms. We explored whether diabetes diminished BAG3/Bcl-2/Nrf-2/HO-1-mediated cardioprotection and overproduced oxidative stress contributing to exaggerated IR injury. Streptozotocin-induced diabetes enhanced hyperglycemia, cardiac NADPH oxidase p22/p67 expression, malondialdehyde amount and leukocyte infiltration, altered the mesenteric expression of 4-HNE, CaSR, p-eNOS and BAG3 and impaired microvascular reactivity to the vasoconstrictor/vasodilator by a wire myography. In response to myocardial IR, diabetes further depressed BAG3/Bcl-2/Nrf-2/HO-1 expression, increased cleaved-caspase 3/poly(ADP-ribose) polymerase (PARP)/TUNEL-mediated apoptosis and exacerbated IR-induced left ventricular dysfunction characterized by further depressed microcirculation, heart rate, left ventricular systolic pressure and peak rate of pressure increase/decrease (±dp/dt) and elevated left ventricular end-diastolic pressure (LVEDP) and Evans blue-2,3,5-triphenyltetrazolium chloride-stained infarct size in diabetic hearts. Our results implicated diabetes exacerbated IR-induced myocardial dysfunction through downregulated BAG3/Bcl-2/Nrf-2/HO-1 expression, increased p22/p67/caspase 3/PARP/apoptosis-mediated oxidative injury and impaired microvascular reactivity.

Activation of NF-κB is a critical element in the antiapoptotic effect of anesthetic preconditioning

2009 ◽  
Vol 296 (5) ◽  
pp. H1296-H1304 ◽  
Author(s):  
Xiyuan Lu ◽  
Hong Liu ◽  
Lianguo Wang ◽  
Saul Schaefer
Keyword(s):  
Cytochrome C ◽  
Caspase 3 ◽  
Diastolic Pressure ◽  
Ischemia Reperfusion ◽  
Left Ventricular ◽  
Reversible Inhibitor ◽  
Critical Element ◽  
Protective Effects ◽  
Anesthetic Preconditioning

Anesthetic preconditioning (APC), defined as brief exposure to inhalational anesthetics before cardiac ischemia-reperfusion (I/R), limits injury in both animal models and in humans. APC can result in the production of reactive oxygen species (ROS), and prior work has shown that APC can modify activation of NF-κB during I/R, with consequent reduction in the expression of inflammatory mediators. However, the role of NF-κB activation before I/R is unknown. Therefore, these experiments tested the hypothesis that APC-induced ROS results in activation of NF-κB before I/R, with consequent increased expression of antiapoptotic proteins such as Bcl-2 and decreased apoptosis. Experiments utilized an established perfused heart rat model of sevoflurane APC and I/R. The role of NF-κB was defined by a novel method of transient inhibition of the regulatory kinase IKK using the reversible inhibitor SC-514. In addition to functional measures of left ventricular developed and end-diastolic pressure, phosphorylation of IκBα and activation of NF-κB were measured along with cytosolic protein content of Bcl-2, release of cytochrome c, and degradation of caspase-3. APC resulted in ROS-dependent phosphorylation of IκBα and activation of NF-κB before I/R. APC also increased the expression of Bcl-2 before I/R. In addition to functional protection following I/R, APC resulted in lower release of cytochrome c and caspase-3 degradation. These protective effects of APC were abolished by transient inhibition of IκBα phosphorylation and NF-κB activation by SC-514 followed by washout. ROS-dependent activation of NF-κB by APC before I/R is a critical element in the protective effect of APC. APC reduces apoptosis and functional impairment by increasing Bcl-2 expression before I/R. Interventions that increase NF-κB activation before I/R should protect hearts from I/R injury.

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