The Protective Effects of Preconditioning With Dioscin on Myocardial Ischemia/Reperfusion-Induced Ventricular Arrhythmias by Increasing Connexin 43 Expression in Rats

2018 ◽  
Vol 24 (3) ◽  
pp. 262-268 ◽  
Author(s):  
Jin Cheng ◽  
Chuang Sun ◽  
Jingyu Zhang ◽  
Qing Zou ◽  
Qimeng Hao ◽  
...  

Myocardial ischemia–reperfusion (IR) injury is associated with high disability and mortality worldwide. This study was to explore the roles of dioscin in the myocardial IR rats and discover the related molecular mechanisms. Rats were divided into 5 groups: sham, IR, IR + 15 mg/kg dioscin, IR + 30 mg/kg dioscin, and IR + 60 mg/kg dioscin. Heart rate (HR), mean arterial blood pressure (MAP), and rate pressure product (RPP) were evaluated at 10 minutes before ischemia, immediately after ischemia, and at the beginning, middle, and end of reperfusion. Arrhythmia score and myocardial infarct size were examined in rats of all groups. The serum creatine kinase-muscle/brain (CKMB) and cardiac troponin I (cTnI) levels were analyzed via enzyme-linked immunosorbent assay. Protein amount of total connexin 43 (T-Cx43) and phosphorylated connexin 43 (P-Cx43) was evaluated by Western blot. Ischemia reperfusion significantly decreased HR, MAP, and RPP of rats compared to the sham group. However, dioscin significantly attenuated the above phenomena in a dose-dependent manner. Dioscin markedly inhibited IR-induced increase in arrhythmias score, infarct size, and serum CKMB and cTnI levels. In addition, dioscin strikingly induced IR-repressed expression of T-Cx43 and P-Cx43. Our results suggested that dioscin pretreatment exhibited protective effects against myocardial IR injury. Moreover, we found that dioscin attenuated myocardial IR-induced ventricular arrhythmias via upregulating Cx43 expression and activation.

2014 ◽  
Vol 934 ◽  
pp. 165-172
Author(s):  
Cai Hong Bai ◽  
Hai Bo He ◽  
Fan Cheng ◽  
Jun Zhi Wang ◽  
Xiao Chen ◽  
...  

Saponins from Rhizoma Panacis Majoris (SRPM), the bioactive component inRhizoma Panacis Majoris, were reported to possess protective effects on myocardial injury, but the underlying mechanisms remain poorly understood. This study was performed to investigate the protective effects and possible mechanism of SRPM on myocardial ischemia/reperfusion (I/R) injury in vivo. Cardioprotective effects of SPRM in I/R rats was evaluated by hemodynamic, infarct size, biochemical values, histopathological observations, antioxidative relative gene expressions; And the antioxidant activity of SPRM was studied using DPPH scavenging and β-carotene/linoleic acid tests. In the study, we found that SRPM possessed significant free radical-scavenging activity and considerable antioxidant activity, and significantly improved cardiac function, serum biochemical index and antioxidation level, decreased infarct size, reversed the down-regulated mRNA expressions of the SOD1, SOD2, SOD3 in I/R rats. The studies demonstrated that oxidative stress caused the overgeneration and accumulation of ROS, which was central of myocardial I/R injury. SPRM exerted beneficially cardioprotective effects on myocardial I/R injury, mainly scavenging oxidative stress-triggered overgeneration and accumulation of ROS, alleviating myocardial I/R injury and apoptotic cell death.


2021 ◽  
Vol 11 ◽  
Author(s):  
Cheng-Yin Liu ◽  
Yi Zhou ◽  
Tao Chen ◽  
Jing-Chao Lei ◽  
Xue-Jun Jiang

Arctigenin, one of the active ingredients extracted from Great Burdock (Arctium lappa) Achene, has been found to relieve myocardial infarction injury. However, the specific mechanism of Arctigenin against myocardial infarction remains largely unknown. Here, both acute myocardial ischemia-reperfusion injury (AMI/R) rat model and oxygen glucose deprivation (OGD)-induced myocardial cell injury model were constructed to explore the underlying role of AMPK/SIRT1 pathway in Arctigenin-mediated effects. The experimental data in our study demonstrated that Arctigenin ameliorated OGD-mediated cardiomyocytes apoptosis, inflammation and oxidative stress in a dose-dependent manner. Besides, Arctigenin activated AMPK/SIRT1 pathway and downregulated NF-κB phosphorylation in OGD-treated cardiomyocytes, while inhibiting AMPK or SIRT1 by the Compound C (an AMPK inhibitor) or SIRT1-IN-1 (a SIRT1 inhibitor) significantly attenuated Arctigenin-exerted protective effects on cardiomyocytes. In the animal experiments, Arctigenin improved the heart functions and decreased infarct size of the AMI/R-rats, accompanied with downregulated oxidative stress, inflammation and apoptotic levels in the heart tissues. What’s more, Arctigenin enhanced the AMPK/SIRT1 pathway and repressed NF-κB pathway activation. Taken together, our data indicated that Arctigenin reduced cardiomyocytes apoptosis against AMI/R-induced oxidative stress and inflammation at least via AMPK/SIRT1 pathway.


2011 ◽  
Vol 301 (3) ◽  
pp. E447-E455 ◽  
Author(s):  
Yanzhuo Ma ◽  
Yi Liu ◽  
Shaowei Liu ◽  
Yan Qu ◽  
Rutao Wang ◽  
...  

The present study determined the dynamic change of adiponectin (APN, a cardioprotective adipokine), its receptor expression, and their impact upon myocardial ischemia/reperfusion (MI/R) injury during type 1 diabetes mellitus (T1DM) progression, and involved underlying mechanisms. Diabetic state was induced in mice via multiple intraperitoneal injections of low-dose streptozotocin. The dynamic change of plasma APN concentration and cardiac APN receptor-1 and -2 (AdipoR1/2) expression were assessed immediately after diabetes onset (0 wk) and 1, 3, 5, and 7 wk thereafter. Indicators of MI/R injury (infarct size, apoptosis, and LDH release) were determined at 0, 1, and 7 wk of DM duration. The effect of APN on MI/R injury was determined in mice subjected to different diabetic durations. Plasma APN levels (total and HMW form) increased, whereas cardiac AdipoR1 expression decreased early after T1DM onset. With T1DM progression, APN levels were reduced and cardiac AdipoR1 expression increased. MI/R injury was exacerbated with T1DM progression in a time-dependent manner. Administration of globular APN (gAD) failed to attenuate MI/R injury in 1-wk T1DM mice, while an AMP-activated protein kinase (AMPK) activator (AICAR) reduced MI/R injury. However, administration of gAD (and AICAR) reduced infarct size and cardiomyocyte apoptosis in 7-wk T1DM mice. In conclusion, our results demonstrate a dynamic dysfunction of APN/AdipoR1 during T1DM progression. Reduced cardiac AdipoR1 expression and APN concentration may be responsible for increased I/R injury susceptibility at early and late T1DM stages, respectively. Interventions bolstering AdipoR1 expression during early T1DM stages and APN supplementation during advanced T1DM stages may potentially reduce the myocardial ischemic injury in diabetic patients.


2021 ◽  
Vol 8 ◽  
Author(s):  
Hui-Hui Guo ◽  
Xin-Yue Jing ◽  
Hui Chen ◽  
Hou-Xi Xu ◽  
Bing-Mei Zhu

Electroacupuncture (EA) can help reduce infarct size and injury resulting from myocardial ischemia/reperfusion (I/R); however, the underlying molecular mechanism remains unknown. We previously reported that STAT5 plays a critical role in the cardioprotective effect of remote ischemic preconditioning (RIPC). Here, we assessed the effects of electroacupuncture pretreatment (EAP) on myocardial I/R injury in the presence and/or absence of Stat5 in mice and investigated whether EAP exerts its cardioprotective effects in a STAT5-dependent manner. Adult Stat5fl/fl and Stat5-cKO mice were exposed to EAP at Neiguan (PC6) for 7 days before the induction of I/R injury by left anterior descending (LAD) coronary artery ligation. The myocardial infarct size (IS), area at risk, and apoptotic rate of cardiomyocytes were detected. RT-qPCR and western blotting were used to measure gene and protein expression, respectively, in homogenized heart tissues. RNA-seq was used to identify candidate genes and pathways. Our results showed that EAP decreased IS and the rate of cardiomyocyte apoptosis. We further found that STAT5 was activated by EAP in Stat5fl/fl mice but not in Stat5-cKO mice, whereas the opposite was observed for STAT3. Following EAP, the levels of the antiapoptotic proteins Bcl-xL, Bcl-2, and p-AKT were increased in the presence of Stat5, while that of interleukin 10 (IL-10) was increased in both Stat5fl/fl and Stat5-cKO. The gene expression profile in heart tissues was different between Stat5fl/fl and the Stat5-cKO mice with EAP. Importantly, the top 30 DEGs under EAP in the Stat5-cKO mice were enriched in the IL-6/STAT3 signaling pathway. Our results revealed for the first time that the protective effect of EAP following myocardial I/R injury was attributable to, but not dependent on, STAT5. Additionally, we found that EAP could activate STAT3 signaling in the absence of the Stat5 gene, and could also activate antiapoptotic, survival, and anti-inflammatory signaling pathways.


2018 ◽  
Vol 49 (4) ◽  
pp. 1646-1658 ◽  
Author(s):  
Xiaoyan Huang ◽  
Yuguang Wang ◽  
Yi Wang ◽  
Liang Yang ◽  
Jia Wang ◽  
...  

Background/Aims: Epoxyeicosatrienoic acids (EETs) are cytochrome P450 epoxygenase (CYP) metabolites of arachidonic acid and have multiple cardiovascular effects. Ophiopogonin D (OP-D) is an important effective monomeric component in Shenmai injection (SM-I). Both have been reported to have a variety of biological functions, including anti-inflammatory, anti-oxidant, and anti-apoptotic effects. We previously demonstrated that OP-D–mediated cardioprotection involves activation of CYP2J2/3 and enhancement of circulating EETs levels in vitro and can be developed as a novel drug for the therapy of myocardial ischemia-reperfusion (MI/R) injury. We therefore hypothesized that the protective effects of OP-D and SM-I against MI/R injury are associated with increased expression of CYP2J3 and enhanced circulating 11,12-EET levels in vivo. Methods: A rat model of MI/R injury was generated by ligation of the left anterior descending coronary artery for 40 min, followed by reperfusion for 2 h to determine the protective effects and potential mechanisms of OP-D and SM-I. Electrocardiogram and ultrasonic cardiogram were used to evaluate cardiac function; 2,3,5-triphenyltetrazolium chloride was used to measure myocardial infarct size; hematoxylin and eosin staining and transmission electron microscopy were used to observe the morphology of myocardial tissue; and the expression of related proteins in the mechanistic study was observed by western blot analysis. Results: We found that OP-D and SM-I exert protective effects on MI/R injury, including regulation of cardiac function, reduction of lactate dehydrogenase and creatine kinase production, attenuation of myocardial infarct size, and improvement of the recovery of damaged myocardial structures. We found that OP-D and SM-I activate CYP2J3 expression and increase levels of circulating 11,12-EET in MI/R-injured rats. Conclusion: We tested the hypothesis that the cardioprotective effects of OP-D and SM-I on MI/R injury are associated with increased expression of CYP2J3 and enhanced circulating 11,12-EET levels in rats. Taken together, our results show that the effects of OP-D and SM-I were also mediated by the activation of the PI3K/Akt/eNOS signaling pathway, while inhibition of the NF-κB signaling pathway and antioxidant and anti-apoptotic effects were involved in the cardioprotective effects of OP-D and SM-I.


2017 ◽  
Vol 42 (6) ◽  
pp. 2295-2306 ◽  
Author(s):  
Waleed Al-Herz ◽  
Fawzi Babiker

Background/Aims: To investigate the cardioprotective effects of intravenous immunoglobulins (IVIG) in rats subjected to regional myocardial ischemia reperfusion (I/R). Methods: Langendorff-perfused rat hearts were used in this study. Hearts subjected to regional ischemia served as a negative untreated control. The effects of IVIG pre- and post-ischemic treatment on left ventricular function, coronary vascular dynamics and contractility were assessed. IVIG were administered in either a low or high dose. The infarct size was determined using triphenyltetrazolium chloride and through biochemical assays using the measured creatine kinase and lactate dehydrogenase levels. Apoptosis was evaluated by the TUNEL assay, and the caspase-3 expression level was assessed by immunoblotting. The cytokine levels were measured by ELISA. Results: Low and high doses of immunoglobulins administered 2 hours before sacrifice, before the ischemic insult or at reperfusion resulted in a significant improvement in cardiac hemodynamics, coronary vascular dynamics and heart contractility. A significant decrease in the infarct size and cardiac enzymes was also evident compared to those in the control. IVIG administered as an infusion at reperfusion or pre-treatment resulted in a marked decrease in myocyte apoptosis, which was associated with decreased levels of caspase-3 expression in the supernatants of homogenized left ventricles. Infusion of IVIG both pre-ischemia and at reperfusion did not show the same protective effects. Conclusions: This study demonstrates a novel protection to the heart by low and high doses of IVIG given either pre- or post-ischemia.


2012 ◽  
Vol 302 (9) ◽  
pp. H1818-H1825 ◽  
Author(s):  
Wei Zhou ◽  
Yoshihiro Ko ◽  
Peyman Benharash ◽  
Kentaro Yamakawa ◽  
Sunny Patel ◽  
...  

Augmentation of cardiac sympathetic tone during myocardial ischemia has been shown to increase myocardial O2 demand and infarct size as well as induce arrhythmias. We have previously demonstrated that electroacupuncture (EA) inhibits the visceral sympathoexcitatory cardiovascular reflex. The purpose of this study was to determine the effects of EA on left ventricular (LV) function, O2 demand, infarct size, arrhythmogenesis, and in vivo cardiac norepinephrine (NE) release in a myocardial ischemia-reperfusion model. Anesthetized rabbits ( n = 36) underwent 30 min of left anterior descending coronary artery occlusion followed by 90 min of reperfusion. We evaluated myocardial O2 demand, infarct size, ventricular arrhythmias, and myocardial NE release using microdialysis under the following experimental conditions: 1) untreated, 2) EA at P5–6 acupoints, 3) sham acupuncture, 4) EA with pretreatment with naloxone (a nonselective opioid receptor antagonist), 5) EA with pretreatment with chelerythrine (a nonselective PKC inhibitor), and 6) EA with pretreatment with both naloxone and chelerythrine. Compared with the untreated and sham acupuncture groups, EA resulted in decreased O2 demand, myocardial NE concentration, and infarct size. Furthermore, the degree of ST segment elevation and severity of LV dysfunction and ventricular arrhythmias were all significantly decreased ( P < 0.05). The cardioprotective effects of EA were partially blocked by pretreatment with naloxone or chelerythrine alone and completely blocked by pretreatment with both naloxone and chelerythrine. These results suggest that the cardioprotective effects of EA against myocardial ischemia-reperfusion are mediated through inhibition of the cardiac sympathetic nervous system as well as opioid and PKC-dependent pathways.


2016 ◽  
Vol 39 (6) ◽  
pp. 2158-2172 ◽  
Author(s):  
Guang Tong ◽  
Ben Zhang ◽  
Xuan Zhou ◽  
Jinbo Zhao ◽  
Zhongchan Sun ◽  
...  

Backgrounds/Aims: The selective κ-opioid agonist U50,488H protects heart from myocardial ischemia-reperfusion (MI/R) injury. We examined whether U50,488H is also beneficial for MI/R induced heart failure. Methods: Anesthetized male Sprague-Dawley rats were subjected to 30 min of myocardial ischemia via left anterior descending coronary artery (LAD) occlusion, followed by 4 weeks of reperfusion. Infarct size was examined by Evans blue/triphenyl tetrazolium chloride (TTC) staining. Cardiac function and remodeling were examined by echocardiography and histology. HO-1 gene transcription and expression were measured by RT-PCR and western blot. Results: Compared to vehicle-treated MI/R rats, rats administered a single dose of U50,488H at the beginning of reperfusion exhibited reduced myocardial infarct size, oxidative stress, hypertrophy, and fibrosis, improved mechanical function, and greater neovascularization. U50,488H also increased myocardial heme oxygenase (HO)-1 gene transcription and expression, while pharmacological HO-1 inhibition reversed all protective effects of U50,488H. Furthermore, U50,488H protected control cultured cardiomyoctes against simulated I/R-induced apoptosis but not cultures subjected to shRNA-mediated HO-1 knockdown. Inhibition of HO-1 in the subacute phase of reperfusion reversed the U50,488H-induced increase in neovascularization and suppression of oxidative stress. Finally, U50,488H increased Akt phosphorylation and nuclear translocation of Nrf2, a key HO-1 transcription activator, while inhibition of PI3K-Akt signaling abolished U50,488H-induced Nrf2 nuclear translocation, HO-1 upregulation, and cardioprotection. Conclusion: Activation of HO-1 expression through the PI3K-Akt-Nrf2 pathway may mediate the acute and long-term protective effects of U50,488H against heart failure by enhancing cardiomyocyte survival and neoangiogenesis and by reducing oxidative stress.


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