Cardioprotective Effects of Combined Therapy with Hyperbaric Oxygen and Diltiazem Pretreatment on Myocardial Ischemia-Reperfusion Injury in Rats

Background/Aims: A combination sevoflurane postconditioning (SPC) and remote ischemic preconditioning (RIPC) is proved effective in an ex vivo rat heart perfusion model. However, the combined effect of those two interventions is not tested in rat myocardial ischemia/reperfusion (I/R) model, and the underlying mechanisms remain to be elucidated. This study aimed to investigate the effect in vivo using a rat myocardial I/R model and illuminate the related mechanisms. Methods: Forty male Sprague-Dawley rats were randomly divided into the following 5 groups: i) sham-operated control; ii) I/R; iii) I/R + RIPC; iv) I/R + SPC; v) I/R + RIPC + SPC. The hemodynamic parameters were recorded at the end of reperfusion. The histological changes including the infarct size were assessed using Triphenyltetrazolium chloride (TTC) staining and H&E staining. In addition, the circulating levels of cardiac enzymes (CK-MB, hs-cTnT, and cTnT) inflammatory cytokines (IL-6, IL-8, and TNF-α) were detected. The expression levels of apoptosis-related proteins (C-Caspase 3, PARP, Bax, and Bcl-2), proinflammatory factors (TLR4, HMGB-1, MyD88, and p65), and IKB-α were measured by Western blot analysis. Real-time PCR was performed to detect mRNA levels of the proinflammatory factors. Results: Both SPC and RIPC significantly reduced the infarct size, cardiac enzyme release, inflammatory cytokine secretion, and proinflammatory factor expression, and increased IKB-α expression compared to I/R group. Furthermore, the combination of those two strategies had synergic infarct size limiting and anti-inflammatory effects. Conclusions: The finding of this study suggested that the combination of SPC and RIPC had a potentially cardioprotective effect through inhibiting TLR4/MyD88/NF-κB signaling.

Section: Discussionmentioning

confidence: 98%

Remote Ischaemic Preconditioning and Sevoflurane Postconditioning Synergistically Protect Rats from Myocardial Injury Induced by Ischemia and Reperfusion Partly via Inhibition TLR4/MyD88/NF-κB Signaling Pathway

Zhang

et al. 2017

“…The myocardial tissue samples were isolated, fixed in 4% paraformaldehyde, embedded in paraffin, and cut into 5 um sections, according to routine histology procedures [4,23]. Next, sections were stained with hematoxylin and eosin (H&E) and examined by light microscopy at 400× magnification.…”

Section: Histopathological Examination Of Myocardial Tissuementioning

confidence: 99%

“…Myocardium undergoing ischemic injury followed by re-establishment of the blood supply generate superabundant oxygen free radicals, triggering oxidative stress, aggravating MIRI, and eventually resulting in mitochondrial dysfunction, cell damage, apoptosis, and necrosis [4]. The bioactive gas, NO, has pro-survival effects that can relieve myocardial I/R injury by scavenging oxygen free radicals, reducing thrombus formation caused by platelet activation, and regulating leukocyte mediated inflammation [26,27].…”

Section: Down-regulation Of Cd47 Attenuates I/r Induced Oxidative Strmentioning

confidence: 99%

“…However, during such procedures, restoration of the blood flow often triggers delayed myocardial dysfunction and damage, termed myocardial ischemia-reperfusion (I/R) injury (MIRI) [3]. A series of studies have demonstrated that inflammation, apoptosis, autophagy, oxygen free radicals, and calcium overload contribute to MIRI; however, there is no completely effective method to prevent or treat this condition [4].…”

Section: Introductionmentioning

confidence: 99%

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RNAi-Mediated Down-Regulation of CD47 Protects against Ischemia/Reperfusion-Induced Myocardial Damage via Activation of eNOS in a Rat Model

Wang

Yang²,

Ding³

et al. 2016

Key Words CD47 • Ischemia/reperfusion injury • Endothelial nitric oxide synthase • Oxidative stress • RNA interferenceAbstract Background/Aims: Oxidative stress is strongly implicated in the pathogenesis of myocardial damage caused by ischemia reperfusion (I/R). Previous studies have confirmed that cardiac CD47 drives left ventricular heart failure. However, the role for CD47 in myocardial I/R injury (MIRI) has not previously been proposed. This study was designed to investigate whether down-regulation of CD47 using RNA interference (RNAi) technology can relieve inhibition of nitric oxide signaling and attenuate myocardial damage in a rat model of I/R. Methods: Male Sprague-Dawley rats (n = 40) were randomly allocated to four groups and pre-treated either with saline (Sham and I/R groups), or adenovirus expressing either control (Ad-EGFP-N) or CD47-targeting (Ad-EGFP-CD47) RNAi. After four days, the rat MIRI model was established by occluding the left anterior descending coronary artery for 30 min, followed by reperfusion for 3 h. Heart tissue was harvested and assessed by immunohistochemistry, western blot, and quantitative RT-PCR. Outcome measures included infarct size, myocardial enzyme (creatine kinase, creatine kinase-MB, and lactate dehydrogenase) levels in serum, markers of oxidative stress, and morphological changes to the myocardium. Results: Delivery of Ad-EGFP-CD47 RNAi into the myocardium remarkably decreased CD47 expression levels. Down-regulation of CD47 was significantly associated with reduced infarct size and serum levels of myocardial enzymes, increased activity of endothelial nitric oxide synthase, increased levels of nitric oxide, and decreased levels of oxidative stress. Conclusion: These data indicate that down-regulation H.-b. Wang and J. Yang contributed equally to this work.

“…Restoration of the coronary blood flow (reperfusion) is essential for the salvage of the ischemic heart, however, reperfusion itself may lead to lethal myocardium injury [1, 2], termed myocardial ischemia reperfusion (I/R) injury. Brief episodes of ischemia and reperfusion applied either before (ischemic preconditioning) or after (ischemic postconditioning) prolonged ischemia protects the hearts against myocardial I/R in non-diabetes.…”

Section: Introductionmentioning

confidence: 99%

Propofol Through Upregulating Caveolin-3 Attenuates Post-Hypoxic Mitochondrial Damage and Cell Death in H9C2 Cardiomyocytes During Hyperglycemia

Deng

Wang

Zhang

et al. 2017

Background/Aims: Hearts from diabetic subjects are susceptible to myocardial ischemia reperfusion (I/R) injury. Propofol has been shown to protect against myocardial I/R injury due to its antioxidant properties while the underlying mechanism remained incompletely understood. Thus, this study aimed to determine whether or not propofol could attenuate myocardial I/R injury by attenuating mitochondrial dysfunction/damage through upregulating Caveolin (Cav)-3 under hyperglycemia. Methods: Cultured rat cardiomyocyte H9C2 cells were subjected to hypoxia/reoxygenation (H/R) in the absence or presence of propofol under high glucose (HG), and cell viability, lactate dehydrogenase (LDH) and mitochondrial viability as well as creatine kinase-MB (CK-MB), cardiac troponin I (cTnI) and intracellular adenosine triphosphate (ATP) content were measured with colorimetric Enzyme-Linked Immunosorbent Assays. Intracellular levels of oxidative stress was assessed using 2,7-dichlorodihydrofluorescein diacetate (DCF-DA) fluorescent staining and mitochondrial-dependent apoptosis was assessed by detecting mitochondrial membrane potential and the activation of apoptotic caspases 3 and 9. Results: Exposure of cells to HG without or with H/R both significantly increased cell injury, cell apoptosis and enhanced oxidative stress that were associated with mitochondrial dysfunction and decreased Cav-3 protein expression. All these changes were further exacerbated following H/R under HG. Administration of propofol at concentrations from 12.5 to 50 µM but not 100 µM significantly attenuated H/R injury that was associated with increased Cav-3 expression and activation of the prosurvival proteins Akt and STAT3 with the optimal protective effects seen at 50 µM of propofol (P25). The beneficial effects of propofol(P25) were abrogated by Cav-3 disruption with β-methyl-cyclodextrin. Conclusion: Propofol counteracts cardiomyocyte H/R injury by attenuating mitochondrial damage and improving mitochondrial biogenesis through upregulating Cav-3 during hyperglycemia.