The Protective Effect of Egr-1 Antisense Oligodeoxyribonucleotide on Myocardial Injury Induced by Ischemia-reperfusion and Hypoxia-reoxygenation

Aims: Our previous studies have shown that N-n-butyl haloperidol iodide (F₂) can antagonize myocardial ischemia/reperfusion (I/R) injury by blocking intracellular Ca²⁺ overload and suppressing Egr-1 overexpression. The present study is to investigate the relation between the reduction of Ca²⁺ overload and the inhibition of Egr-1 overexpression. Methods: The Sprague-Dawley rat myocardial I/R model and cultured cardiomyocyte hypoxia-reoxygenation (H/R) model were established. Administration of Egr-1 antisense oligodeoxyribonucleotide (AS-ODN) only or combining with F₂, Egr-1 protein expression was examined by Western-blot analyses. Hemodynamic parameters, creatine kinase (CK) and lactate dehydrogenase (LDH), superoxide dismutase (SOD) and malondialdehyde (MDA), myeloperoxidase (MPO), cardiac troponin I (cTnI), and tumor necrosis factor-α (TNF-α) were measured to assess the degree of injury and inflammation of myocardial tissues and cells. Results: Treatment with Egr-1 AS-ODN significantly reduced Egr-1 protein expression and attenuated injury and inflammation of myocardium caused by I/R or H/R evidenced by the amelioration of hemodynamics, the decrease in leakage of CK, LDH, cTnI, the increase in MDA generation, the decrease in SOD activity, the reduction of MPO activity in myocardial tissues and release of TNF-α from cultured cardiomyocytes. Treatment with F₂ combined with Egr-1 AS-ODN, the inhibition of Egr-1 protein expression and inflammation (MPO activity and TNF-α level) were not enhanced, but the protection from myocardial I/R (or H/R) injury was significantly increased in hemodynamics and cytomembrane permeability relative to the using of Egr-1 AS-ODN only. Conclusion: These data suggest that the inhibition of Egr-1 overexpression cannot involve all mechanisms of cardioprotection from I/R injury.

Section: Introductionsupporting

confidence: 76%

Egr-1, a Central and Unifying Role in Cardioprotection from Ischemia-Reperfusion Injury?

Gao

Jia²,

Guo³

et al. 2009

“…Lo et al employed bovine aortic endothelial cells with hypoxia and found that Egr-1 mRNA expression rapidly increased within 30 minutes [9]. These results showed that Egr-1 expression of endothelial cells occurs more quickly than that of cardiomyocytes, which noticeably begins at 1 hour after reperfusion [13,16]. According to the recent data, levels of Egr-1 expression are upregulated in various organs including the heart [24], lung [3,25], gut [26] and kidney [27] after I/R challenge.…”

Section: Discussionmentioning

confidence: 99%

“…Sequence of antisense Egr-1 ODN was 3'-TAC CGT CGC CGG TTC -5' as described previously [16]. For control experiments, scrambled-sequence Egr-1 ODNs (3'-TCG TGC CGC TGC CAT -5') were used [1].…”

Section: Preparation Of Antisense and Scrambled-sequence Egr-1 Oligodmentioning

confidence: 99%

<i>N</i>-n-butyl Haloperidol Iodide Protects Cardiac Microvascular Endothelial Cells From Hypoxia/Reoxygenation Injury by Down-Regulating Egr-1 Expression

Zhou¹,

Zhang²,

Gao³

et al. 2010

Self Cite

Aims: Our previous studies have shown that N-n-butyl haloperidol iodide (F2) can antagonize myocardial ischemia/reperfusion (I/R) injury by down-regulating the early growth response (Egr)-1 expression, but the molecular mechanisms are not well understood. Because there is evidence implicating myocardial I/R injury is closely associated with endothelial dysfunction. The present study is to test the hypothesis that the protective effects of F2 on myocardial I/R injury is related closely with down-regulating Egr-1 expression on cardiac microvascular endothelial cells (CMECs). Methods: A model of cultured CMECs exposed to hypoxia/reoxygenation (H/R) was developed. With antisense Egr-1 oligodeoxyribonucleotide (ODN), the relationship between Egr-1 expression and endothelial H/R injury was investigated. Egr-1 mRNA and protein expression were examined by real-time fluorescent quantitative PCR, immunocytochemical staining and Western-blot analysis. Lactate dehydrogenase (LDH), malondialdehyde (MDA), superoxide dismutase (SOD), intercellular adhesion molecule-1 (ICAM-1), adherence of neutrophil and platelets, and cell viability were measured after H/R to evaluate the degree of endothelial injury. Results: Pretreatment with antisense Egr-1 ODN significantly reduced Egr-1 protein expression and attenuated injury of CMECs. Consistent with down-regulation of Egr-1 expression by F2, inflammation and other damage were significantly reduced as evidenced by a decrease of ICAM-1 expression, reduction of neutrophil and platelets adherence, increase in SOD, and decreases in MDA and LDH levels, resulting in the rise of cell viability. Conclusions: We demonstrate a protective effect of F2 in CMECs against H/R injury by down-regulating Egr-1 expression, which might be play a vital role in the pathogenesis of myocardial I/R injury.

“…Ca 2+ overload during reperfusion may occur by several mechanisms. One mechanism is related to increased Ca 2+ influx through 18 Ca 2+ channels. The second mechanism is the reduced Ca 2+ reuptake by the sarcoplasmatic reticulum.…”

Section: Introductionmentioning

confidence: 99%

“…These findings indicate that the overexpression of Egr-1 could be the common denominator in ischemia/reperfusion injury in various organs, so it might be a good therapeutic target in ischemia/ reperfusion conditions. Our previous study involving antisense Egr-1 oligodeoxyribonucleotides suggested that overexpression of Egr-1 was a causal factor in myocardial ischemia/reperfusion or hypoxia/reoxygenation injury, and F 2 could protect myocardial tissues and cells against ischemia/reperfusion or hypoxia/reoxygenation injury, which was largely due to the inhibition of Egr-1 overexpresssion [17,18].…”

Section: Introductionmentioning

confidence: 99%

<i>Egr-1</i>, the Potential Target of Calcium Channel Blockers in Cardioprotection with Ischemia/Reperfusion Injury in Rats

Huang¹,

Li²,

Guo³

et al. 2009

Self Cite

Aims: In this study, we tested whether Egr-1 is a potential target of calcium channel blockers in cardioprotection with I/R injury. Methods: We treated rats in vivo I/R and rat cultured cardiomyocytes in vitro hypoxia/reoxygenation (H/R) models with three types of classical calcium channel blockers (verapamil, diltiazem and nifedipine). Activity of creatine kinase (CK), lactate dehydrogenase (LDH), myeloperoxidase (MPO) superoxide dismutase (SOD) and level of malondialdehyde (MDA) in plasma and culture medium were measured to assess the degree of injury and inflammation of myocardial tissues and cells. Egr-1 mRNA and protein expressions were examined by RT-PCR and Western-blot analyses. Results: Calcium channel blockers (verapamil, diltiazem and nifedipine) significantly attenuated myocardial injury, as shown by reduced release of CK and LDH, preserved SOD activity and decreased MDA production and MPO activity. Concomitant with cardioprotection by calcium channel blockers, the mRNA and protein expression of Egr-1 increased with I/R and H/R injury was significantly reduced in myocardial tissue and cultured cardiomyocytes. Conclusions: These results suggested that the cardioprotective effects of calcium channel blockers with I/R or H/R injury might be mediated by downregulating Egr-1 expression. Egr-1 might be the potential target of calcium channel blockers in cardioprotection with ischemia/reperfusion injury.