scholarly journals Diazoxide Post-conditioning Activates the HIF-1/HRE Pathway to Induce Myocardial Protection in Hypoxic/Reoxygenated Cardiomyocytes

2021 ◽  
Vol 8 ◽  
Author(s):  
Xi-Yuan Chen ◽  
Jia-Qi Wang ◽  
Si-Jing Cheng ◽  
Yan Wang ◽  
Meng-Yuan Deng ◽  
...  
Keyword(s):  
Myocardial Protection ◽  
Ischemia Reperfusion Injury ◽  
Ischemia Reperfusion ◽  
Hypoxia Inducible Factor ◽  
Cellular Damage ◽  
Protective Mechanism ◽  
Necrosis Factor Alpha ◽  
Protein Levels ◽  
Conditioning Treatment ◽  
Myocardial Ischemia Reperfusion

Background: Previous studies have shown that diazoxide can protect against myocardial ischemia-reperfusion injury (MIRI). The intranuclear hypoxia-inducible factor-1 (HIF-1)/hypoxia-response element (HRE) pathway has been shown to withstand cellular damage caused by MIRI. It remains unclear whether diazoxide post-conditioning is correlated with the HIF-1/HRE pathway in protective effect on cardiomyocytes.Methods: An isolated cardiomyocyte model of hypoxia-reoxygenation injury was established. Prior to reoxygenation, cardiomyocytes underwent post-conditioning treatment by diazoxide, and 5-hydroxydecanoate (5-HD), N-(2-mercaptopropionyl)-glycine (MPG), or dimethyloxallyl glycine (DMOG) followed by diazoxide. At the end of reoxygenation, ultrastructural morphology; mitochondrial membrane potential; interleukin-6 (IL-6), tumor necrosis factor alpha (TNF-α), reactive oxygen species (ROS), and HIF-1α levels; and downstream gene mRNA and protein levels were analyzed to elucidate the protective mechanism of diazoxide post-conditioning.Results: Diazoxide post-conditioning enabled activation of the HIF-1/HRE pathway to induce myocardial protection. When the mitoKATP channel was inhibited and ROS cleared, the diazoxide effect was eliminated. DMOG was able to reverse the effect of ROS absence to restore the diazoxide effect. MitoKATP and ROS in the early reoxygenation phase were key to activation of the HIF-1/HRE pathway.Conclusion: Diazoxide post-conditioning promotes opening of the mitoKATP channel to generate a moderate ROS level that activates the HIF-1/HRE pathway and subsequently induces myocardial protection.

scholarly journals Protective Effect and Mechanism of Total Flavones fromRhododendron simsiiPlanch Flower on Cultured Rat Cardiomyocytes with Anoxia and Reoxygenation

2015 ◽  
Vol 2015 ◽  
pp. 1-10 ◽  
Author(s):  
Yi Jiao ◽  
Yi-Fei Fan ◽  
Yu-Ling Wang ◽  
Jun-Yan Zhang ◽  
Shuo Chen ◽  
...  
Keyword(s):  
Myocardial Infarction ◽  
Protective Effect ◽  
Cell Viability ◽  
Ischemia Reperfusion ◽  
Cellular Damage ◽  
Protective Mechanism ◽  
Patch Clamp Technique ◽  
Rat Cardiomyocytes ◽  
Whole Cell Patch Clamp ◽  
Myocardial Ischemia Reperfusion

Many flavonoids have cardioprotection against myocardial ischemia/reperfusion (I/R) injury. Total flavones fromRhododendron simsiiPlanch flower (TFR) can protect myocardial ischemic injuries. However, its protective mechanism is still unknown. The present study was designed to investigate the mechanism of TFR on myocardial I/R and anoxia/reoxygenation (A/R) injuries. Rat model of myocardial I/R injury was made, and myocardial infarction was determined. A/R injury was induced in cultured rat cardiomyocytes; cellular damage was evaluated by measuring cell viability, LDH and cTnT releases, and MDA content. Expressions of ROCK1and ROCK2protein were examined by Western blot analysis, and K+currents were recorded by using whole-cell patch clamp technique. TFR 20~80 mg/kg markedly reduced I/R-induced myocardial infarction. TFR 3.7~300 mg/L significantly inhibited A/R-induced reduction of cell viability, LDH and cTnT releases, and MDA production. Exposure to A/R significantly increased ROCK1and ROCK2expressions in rat cardiomyocytes, but TFR 33.3~300 mg/L obviously inhibited this increase. 300 mg/L TFR significantly augmented inward rectifier K+current and other K+currents in rat cardiomyocytes. These results indicate that TFR has a protective effect on rat cardiomyocytes A/R damage, and the protective mechanism may be engaged with the inhibition of ROCK1and ROCK2and activation of K+channels.

Abstract 221: miR-19b Protects Myocardial Ischemia Reperfusion Injury

2015 ◽  
Vol 117 (suppl_1) ◽  
Author(s):  
Dongchao Lv ◽  
Shengguang Ding ◽  
Ping Chen ◽  
Yihua Bei ◽  
Chongjun Zhong ◽  
...  
Keyword(s):  
Reperfusion Injury ◽  
Cellular Proliferation ◽  
Ischemia Reperfusion Injury ◽  
Ischemia Reperfusion ◽  
H9c2 Cells ◽  
Protein Levels ◽  
Myocardial Ischemia Reperfusion Injury ◽  
Myocardial Ischemia Reperfusion ◽  
Induced Apoptosis

Ischemia-reperfusion injury (IRI) following acute myocardial infarction (AMI) has no effective treatment and a poor prognosis. microRNA (miRNA)-19b is a key functional member of miRNA-19-72 cluster family, regulating cellular proliferation, apoptosis, differentiation, and metabolism. Dysregulation of the miR-19b cluster is critically involved in a spectrum of cardiovascular diseases. However, the role of miR-19b in myocardial IRI is unknown. In this study, we found that miR-19b was downregulated in a mouse model of IRI. Meanwhile, about 50% downregulation of miR-19b was detected in H2O2-treated H9C2 cells mimicking myocardial IRI. We also found that overexpression of miR-19b decreased H2O2-induced apoptosis (36.02%±3.92% vs 29.34%±0.79% in nc-mimics vs miR-19b-mimics, respectively) and necrosis (23.11%±1.64% vs 18.76%±0.71% in nc-mimics vs miR-19b-mimics, respectively), and increased proliferation of H9C2 cells in vitro, while downregulation of miR-19b had reverse effects. Furthermore, PTEN, a previously validated target gene of miR-19b, has been found to be negatively regulated by miR-19b at protein levels in H9C2 cells. These data reveal the potential of miR-19b as a therapeutic target for myocardial IRI.

scholarly journals Dexmedetomidine mitigates myocardial ischemiareperfusion injury via regulation of HMGB1-TLR4-NF-κB signaling axis

2021 ◽  
Vol 20 (11) ◽  
pp. 2273-2278
Author(s):  
Ting Wen ◽  
Ia Liu ◽  
Shibiao Chen ◽  
Benchao Hou ◽  
Gan Li ◽  
...  
Keyword(s):  
Heart Muscle ◽  
Sham Group ◽  
Ischemia Reperfusion Injury ◽  
Ischemia Reperfusion ◽  
Myocardial Damage ◽  
Sprague Dawley ◽  
Protein Levels ◽  
Signaling Axis ◽  
Myocardial Ischemia Reperfusion Injury ◽  
Myocardial Ischemia Reperfusion

Purpose: To study the effect of dexmedetomidine (Dex) on myocardial ischemia-reperfusion injury (MIRI), and the associated mechanism of action.Methods: Sixty Sprague-Dawley (SD) rats were assigned to sham, ischemia-reperfusion (I/R), Dex, and MD groups (methyllycaconitine prior to injection with Dex), with 15 rats in each group. Pathological changes in myocardial tissues were determined in all groups. Protein expression levels of HMGB1, TLR4, NF-κB and myeloid differentiation protein 88 (MyD88) in serum and myocardial tissues were assayed and compared.Results: Protein levels of HMGB1, TLR4, MyD88 and NF-κB were significantly higher in heart muscle I/R rats than those in sham group, but lower in heart muscle of rats in Dex group than in heart muscle of I/R rats (p < 0.05). However, they were significantly up-regulated in MD group, relative to Dex group (p< 0.05).Conclusion: Dex exerts a protective effect against ischemia/reperfusion-induced myocardial damage via HMGB1-TLR4-NF-κB signal axis via CAP, and thus, is a potential agent for the management of myocardial disease.

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