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Objective:To observe the effects of electroacupuncture preconditioning on the autophagy-related pathway protein kinase B (Akt)/mammalian target of rapamycin (mTOR) in myocardial tissue of rats with myocardial ischemia reperfusion injury (MIRI); To investigate the protective mechanism of "Neiguan"(PC 6) on myocardial injury.Methods:Totally 48 SD rats were randomly divided into blank group, sham-operation group, model group and Neiguan group ( n=12 in each group). The Neiguan group was applied to bilateral "Neiguan"(PC 6) by electroacupuncture for 30 min, once daily for consecutive 7 days before model replication. Except in the blank group, the MIRI model was established by ligation of the descending anterior branch of the left coronary artery in the rest groups after the intervention. The histomorphological changes in the myocardium of the rats were observed by HE staining, and the expression levels of Akt, phosphorylated Akt (p-Akt), mTOR and phosphorylated mTOR (p-mTOR) in the myocardium were measured by protein immunoblotting. The ratio of p-Akt/Akt and p-mTOR/mTOR was calculated. Results:In the blank group, the myocardial fibres were arranged regularly and neatly, and no inflammatory cell infiltration or haemorrhage was seen in the interstitium; in the sham-operation group, the arrangement of myocardial fibers was slightly irregular, no rupture was found, and a small amount of myocardial fiber gap was slightly enlarged; in the model group, the distribution of myocardial fibers was disordered, hypertrophic cardiomyocytes increased, some mitochondria were red and swollen or the outer membrane was ruptured, and inflammatory infiltration and hemorrhage were seen in the interstitium; the extent of myocardial lesions in the Neiguan group was less than that in the model group, with a small amount of interstitial hemorrhage and inflammatory cell infiltration. There was no statistical significance in the levels of Akt and mTOR in the myocardial tissues of the rats in each group ( P>0.05); compared with the sham-operation group, the levels of p-Akt, p-mTOR and p-Akt/Akt, p-mTOR/mTOR in the model group decreased ( P<0.01); compared with the model group, the levels of p-Akt, p-mTOR and p-Akt/Akt, p-mTOR/mTOR in the Neiguan group increased ( P<0.01). Conclusion:Electroacupuncture preconditioning may inhibit excessive autophagy by activating the Akt/mTOR pathway in cardiomyocytes of MIRI rats, thereby exerting a protective effect on the myocardium.
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Objective:To predict the mechanism of Danggui Buxue Decoction for anti-myocardial ischemia-reperfusion injury and "treating different diseases with the same method" in ischemic stroke based on network pharmacology and molecular docking.Methods:The active components and targets of Danggui Buxue Decoction were screened by retrieving the database of TCMSP and literature; the corresponding targets of myocardial ischemia-reperfusion injury and ischemic stroke were found by OMIM and GeneCards database; the intersection targets of Danggui Buxue Decoction and disease were obtained by using Venny diagram, and the common target network and protein-protein interaction network were constructed by Cytoscape 3.7.1 software and STRING database. The GO and KEGG pathways were enriched by David Database, and the Bio GPS database was used to obtain the tissue distribution information of the key targets. The molecular docking technology was used to verify the results.Results:There were 21 active components in Danggui Buxue Decoction, 181 effective targets and 93 cross targets with diseases. The key components were quercetin, Kaempferol, β-sitosterol, formononetin and isorhamnetin. The key targets were AKT1, TNF, IL6, IL-1β and VEGFA. The enrichment results showed that the main action pathways were fluid shear force and arteriosclerosis, lipid and arteriosclerosis, AGE-RAGE signal pathway in diabetic complications, and the core targets were mainly located in the medullary cells, dendritic cell, smooth muscle, prostate, thyroid and other tissues. The results of molecular docking showed that quercetin had the best binding effect to IL-1β, while isorhamnetin had the best binding effect to IL-1β.Conclusion:Danggui Buxue Decoction is against myocardial ischemia-reperfusion injury and ischemic stroke through hemodynamics, lipid metabolism, inflammatory reaction, oxidative stress, immune reaction and cell apoptosis, plays the role of "treating different diseases with the same method".
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Objective:To evaluate the effect of metformin preconditioning on adenosine monophosphate-activated protein kinase(AMPK)/PTEN-induced putative protein kinase(PINK1) signaling pathway during ischemia-reperfusion (I/R) injury in diabetic rats.Methods:Thirty-six clean-grade healthy male Sprague-Dawley rats, aged 6 weeks, weighing 120-160 g, were divided into 3 groups ( n=12 each) by the random number table method: diabetic sham operation group (DS group), diabetic myocardial I/R group (DI/R group) and diabetic myocardial I/R+ metformin preconditioning group(DI/R+ Met group). After 4 weeks of feeding a high-fat and high-glucose diet, the model of type 2 diabetes mellitus was induced by a single intraperitoneal injection of 1% streptozotocin 40 mg/kg. The myocardial I/R injury was induced by blocking the anterior descending branch of the left coronary artery for 30 min followed by 120-min reperfusion in anesthetized animals. In DI/R+ Met group, metformin 200 mg/kg was given by intragastric gavage once a day within 1 week before myocardial ischemia. Blood samples from the femoral vein were collected at 120 min of reperfusion for determination of the serum creatine kinase isoenzymes (CK-MB) and cardiac troponin I (cTnI) concentrations by enzyme-linked immunosorbent assay. Then the rats were sacrificed and myocardial tissues were obtained for examination of the pathological changes(by HE staining) and for determination of the percentage of myocardial infarct size (by the double staining of Ewan blue and TTC) and expression of myocardial autophagy-related protein Beclin-1, PTEN-induced putative kinase 1 (PINK1), phosphorylated 5′-adenosine monophosphate-activating protein kinase (p-AMPK), and ratio of microtubule-associated protein 1 light chain 3Ⅱ/Ⅰ (LC3Ⅱ/Ⅰ) (by Western blot). Results:Compared with DS group, the percentage of myocardial infarct size and serum CK-MB and cTnI concentrations were significantly increased, the expression of Beclin-1, p-AMPK and PINK1 in myocardial tissues was up-regulated, the ratio of LC3II/I was increased( P<0.05), and the pathological changes were aggravated in DI/R group and DI/R+ Met group. Compared with DI/R group, the percentage of myocardial infarct size and serum CK-MB and cTnI concentrations were significantly decreased, the expression of Beclin-1, p-AMPK and PINK1 in myocardial tissues was up-regulated, the ratio of LC3Ⅱ/Ⅰ was increased ( P<0.05), and the pathological changes were significantly reduced in DI/R+ Met group. Conclusions:The mechanism by which metformin preconditioning reduces myocardial I/R injury is related to activation of AMPK/PINK1 signaling pathway and up-regulation of mitochondrial autophagy in diabetic rats.
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Objective:To evaluate the role of bilateral superior cervical sympathetic ganglia (SCG) in myocardial ischemia-reperfusion (I/R) injury in mice and the relationship with NOD-like receptor protein 3 (NLRP3) inflammasomes.Methods:Thirty-two healthy SPF male C57BL mice, aged 8-10 weeks, weighing 25-30 g, were divided into 4 groups ( n=8 each) by the random number table method: sham operation group (NS group), myocardial I/R group (NIR group), bilateral SCG excision group (SCGx group) and bilateral SCG excision + myocardial I/R group (SCGx+ IR group). The myocardial I/R injury model was prepared by ligating the anterior descending branch of the left coronary artery for 30 min followed by 24 h reperfusion in isoflurane-anesthetized mice. Bilateral superior cervical sympathectomy was performed at 3 days before reperfusion. Blood samples were collected from the inferior vena cava at 24 h of reperfusion for examination of pathological changes (by HE and WGA staining) and for measurement of serum creatine kinase isoenzymes (CK-MB) activity, cardiac troponin I (cTnI) concentration, norepinephrine (NE) concentration and lactic dehydrogenase (LDH) activity (by enzyme-linked immunosorbent assay), superoxide dismutase (SOD) activity (by colorimetric method), myocardial reactive oxygen species (ROS) level (by DHE method), myocardial infarct size(by TTC method), and expression of interleukin-1beta (IL-1β), IL-6, IL-10, tumor necrosis factor-alpha (TNF-α), NLRP3 mRNA (by quantitativepolymerase chain reaction ), and expression of tyrosine hydroxylase (TH), IL-1β, TNF-α, NLRP3, atrial natriuretic peptide (ANP)and brain natriuretic peptide (BNP) (by Western blot). Results:Compared with NS group, the NE concentration was significantly decreased, and TH expression was down-regulated in SCGx group, and the serum CK-MB activity, concentrations of cTnI and NE, LDH activity and myocardial ROS level were significantly increased, SOD activity was decreased, the expression of IL-1β, TNF-α, NLRP3, ANP and BNP was up-regulated, and the expression of IL-1β, IL-6, TNF-α and NLPR3 mRNA was up-regulated in NIR group ( P<0.05). Compared with SCGx group, the serum CK-MB activity, concentrations of cTnI and NE, LDH activity and myocardial ROS levels were significamtly increased, SOD activity was decreased, the expression of IL-1β, TNF-α, NLRP3, ANP and BNP was up-regulated, and the expression of IL-1β, IL-6, TNF-α and NLPR3 mRNA was up-regulated in SCGx+ NIR group ( P<0.05). Compared with NIR group, the serum CK-MB activity, cTnI concentration, LDH activity and myocardial ROS level were significantly decreased, SOD activity was increased, the expression of IL-1β, TNF-α, NLRP3, ANP and BNP was down-regulated, the expression of IL-1β, IL-6, TNF-α and NLPR3 mRNA was down-regulated, and myocardial infarct size was decreased in SCGx+ NIR group ( P<0.05). Conclusions:The mechanism by which bilateral SCG excision attenuates myocardial I/R injury is associated with decreased NLRP3 inflammatory inflammasome activation and inhibition of inflammatory responses in mice.
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Objective:To evaluate the effect of superior cervical ganglion block (SCGB) on cardiac function and nucleotide like receptor protein 3 (NLRP3) signaling pathway in a rat model of myocardial ischemia-reperfusion (I/R).Methods:Sixty healthy SPF male Sprague-Dawley rats, weighing 250-300 g, aged 2-3 months, were divided into 4 groups ( n=15 each) using a random number table method: sham operation group (sham group), myocardial I/R group (IR group), myocardial I/R + normal saline group (IR+ NS group), and myocardial I/R + SCGB group (IR+ SCGB group). Myocardial I/R model was developed by ligation of the left anterior descending branch of the coronary artery for 45 min followed by restoration of blood flow in anesthetized aninals. IR+ SCGB group received SCGB (0.25% ropivacaine 0.1 ml) at 10 min before reperfusion once a day for 2 consecutive weeks, while 0.9% sodium chloride was given instead of ropivacaine in IR+ NS group. Blood samples were collected at 24 h and 14 days of reperfusion for determination of serum concentrations of norepinephrine (NE), troponin T (TnT), tumor necrosis factor-alpha (TNF-α), interleukin-18 (IL-18) and IL-1β by enzyme-linked immunosorbent assay. Echocardiography was performed before ischemia and at 14 days of reperfusion, and left ventricular short axis shortening rate (FS), ejection fraction (EF), and cardiac output (CO) were measured. The rats were sacrificed at 14 days of reperfusion and the hearts were taken for determination of the contents of norepinephrine (NE) in myocardial tissues in the infarction area (by enzyme-linked immunosorbent assay), percentage of myocardial fibrosis area (by Masson staining), M1 macrophage marker CD68 + cell count in the infarction area (by immunohistochemical method), and expression of NLRP3 and gasdermin D (GSDMD) in myocardial tissues (by Western blot). Results:Compared with Sham group, the serum concentrations of TnT, TNF-α, IL-18 and IL-1β, percentage of myocardial fibrosis area, and NE levels in serum and myocardial tissues were significantly increased, the expression of NLRP3 and GSDMD in myocardial tissues was up-regulated, CD68 + cell count was increased, and EF, CO and FS were decreased in IR group ( P<0.05). Compared with IR group, the serum concentrations of TnT, TNF-α, IL-18 and IL-1β, percentage of myocardial fibrosis area, and NE levels in serum and myocardial tissues were significantly decreased, the expression of NLRP3 and GSDMD in myocardial tissues was down-regulated, CD68 + cell count was decreased, and EF, CO and FS were increased in IR+ SCGB group ( P<0.05), and no statistically significant changes were found in the parameters mentioned above in IR+ NS group ( P>0.05). Conclusions:SCGB can improve the cardiac function in a rat model of myocardial I/R, and the mechanism may be related to the inhibition of NLRP3 signaling pathway.
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Objective:To evaluate the role of succinate dehydrogenase (SDH) in hypoxic postconditioning (HPC)-induced reduction of hypoxia-reoxygenation (H/R) injury in myocardial cells of rats and the relationship with mitochondrial ATP-sensitive potassium channels (mito-K ATP). Methods:Myocardial cells isolated from adult male Sprague-Dawley rats were cultured for 48 h and then divided into 7 groups ( n=24 each) using a random number table method: blank control group (Nor group), H/R group, SDHA-siRNA adenovirus+ H/R group (siRNA+ H/R group), HPC group, SDHA-siRNA adenovirus+ HPC group (siRNA+ HPC group), 5-HD+ HPC group, and SDHA-siRNA adenovirus+ 5-HD+ HPC group (siRNA+ 5-HD+ HPC group). Nor group was continuously cultured for 195 min under normoxic conditions. The H/R injury model was prepared by exposing the cells to hypoxia for 45 min in 5% CO 2 + 1% O 2 + 94% N 2, followed by reoxygenation for 150 min. The HPC method involved three cycles of 5 min reoxygenation/5 min hypoxia at the end of 45 min ischemia before 120 min reoxygenation. The mito-K ATP blocker 5-HD administration method involved adding 5-HD at a final concentration of 100 μmol/L at 30 min of hypoxia. The myocardial cells in each siRNA group were successfully transfected with SDHA-siRNA adenovirus to silence SDHA expression. The cell viability, calcium ion level, SDH activity, ATP content, degree of mitochondrial permeability transition pore (mPTP) opening, and mitochondrial membrane potential (MMP) were measured at the end of reoxygenation. Results:Compared with Nor group, the cell viability, ATP content and MMP were significantly decreased, and the degree of mPTP opening, level of calcium ion and activity of SDH were increased in H/R group ( P<0.05). Compared with H/R group, the cell viability, ATP content and MMP were significantly increased, and the degree of mPTP opening, calcium ion level and SDH activity were decreased in siRNA+ H/R group and HPC group ( P<0.05). Compared with HPC group, the cell viability, ATP content and MMP were significantly decreased, and the degree of mPTP opening, calcium ion level and SDH activity were increased in 5-HD+ HPC group ( P<0.05), and the cell viability, ATP content and MMP were significantly increased, and the degree of mPTP opening, calcium ion level and SDH activity were decreased in siRNA+ HPC group ( P<0.05). Compared with siRNA+ HPC group, the cell viability, ATP content and MMP were significantly decreased, the opening degree of mPTP and calcium ion level were increased ( P<0.05), and no significant change was found in the SDH activity in siRNA+ 5-HD+ HPC group ( P>0.05). Compared with 5-HD+ HPC group, the SDH activity was significantly decreased, and no significant change was found in the other parameters in siRNA+ 5-HD+ HPC group ( P>0.05). Conclusions:HPC alleviates H/R injury probably by reducing SDH activity and opening mito-K ATP in myocardial cells of rats.
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Objective:To evaluate the relationship between microRNA-27a (miR-27a) and silent information regulator 1 (SIRT1) during myocardial ischemia-reperfusion (I/R) in rats.Methods:Fifty clean-grade healthy male Sprague-Dawley rats, aged 2-3 months, weighing 220-280 g, were divided into 5 groups ( n=10 each) by the random number table method: sham operation group (Sham group), myocardial I/R group (I/R group), AAV9-miR-27a overexpression + myocardial I/R group (AAV+ I/R group), miR-27a antagomir + myocardial I/R group (AG+ I/R group) and AAV9-miR-27a negative control+ myocardial I/R group (NC+ I/R group). The myocardial I/R injury model was prepared by ligating the anterior descending branch of the left coronary artery for 30 min followed by 120 min reperfusion. At day 14 before ischemia, AAV9-miRNA-27a adeno-associated virus 2×10 11 v. g was injected via the tail vein in AAV+ I/R group, and AAV9-miR-27a NC 2×10 11 v. g was injected via the tail vein in NC+ I/R group. miR-27a antagomir 10 mg/kg was injected via the tail vein once a day at 3 days before ischemia in AG+ I/R group. At the end of 120 min of reperfusion, serum cardiac troponin T(cTnT), creatine kinase isoenzymes (CK-MB) and lactic dehydrogenase (LDH) concentrations and contents of glutathione (GSH), superoxide dismutase (SOD) and malondialdehyde (MDA) in myocardial tissues were determined by enzyme-linked immunosorbent assay, the percentage of myocardial infarct volume by TTC staining, the expression of miR-27a in myocardial tissues by quantitative real-time polymerase chain reaction, and the expression of SIRT1 in myocardial tissues by Western blot. Results:Compared with Sham group, the percentage of myocardial infarct volume and serum concentrations of cTnT, CK-MB and LDH were significantly increased, the contents of GSH and SOD in myocardial tissues were decreased, MDA contents were increased, miR-27a expression was up-regulated, and SIRT1 expression was down-regulated in I/R group ( P<0.05). Compared with I/R group, the percentage of myocardial infarct volume and serum concentrations of cTnT, CK-MB and LDH were significantly increased, the contents of GSH and SOD in myocardial tissues were decreased, MDA contents were increased, miR-27a expression was up-regulated, and SIRT1 expression was down-regulated in AAV+ I/R, and the percentage of myocardial infarct volume and serum concentrations of cTnT, CK-MB and LDH were significantly decreased, the contents of GSH and SOD in myocardial tissues were increased, MDA contents were decreased, miR-27a expression was down-regulated, and SIRT1 expression was up-regulated in AG+ I/R group ( P<0.05), and no significant change was found in the parameters mentioned above in NC+ I/R group ( P>0.05). Compared with AAV+ I/R group, the percentage of myocardial infarct volume and serum concentrations of cTnT, CK-MB and LDH were significantly decreased, the contents of GSH and SOD in myocardial tissues were increased, MDA contents were decreased, miR-27a expression was down-regulated, and SIRT1 expression was up-regulated in AG+ I/R group ( P<0.05). Conclusions:miR-27a is involved in the pathophysiological mechanism underlying myocardial I/R injury probably through inhibition of SIRT1 expression in rats.
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Objective:To evaluate the role of cold-inducible RNA-binding protein (CIRP) in acute renal injury in a mouse model of myocardial ischemia-reperfusion (I/R) and the relationship with nuclear factor kappa B (NF-κB) signaling pathway.Methods:Twenty-four SPF-grade healthy male C57BL/6 mice, aged 6-8 weeks, with body mass index of 24-28 g, were divided into 3 groups ( n=8 each) using a random number table method: sham operation group (Sham group), myocardial I/R group (I/R group) and myocardial I/R + CIRP-derived peptide C23 group (I/R+ C23 group). The model of myocardial I/R was developed by ligation of the left anterior descending coronary artery for 30 min followed by 120-min reperfusion in anesthetized animals. CIRP-derived peptide C23 8 mg/kg was intraperitoneally injected before myocardial ischemia and reperfusion in I/R+ C23 group, while Sham group was only threaded without ligation. Blood samples were collected from the right internal carotid artery at 120 min of reperfusion for determination of the serum creatine kinase isoenzymes (CK-MB), lactic dehydrogenase (LDH), creatinine (Cr) and blood urea nitrogen (BUN) concentrations. Renal tissues were obtained for examination of the pathological changes, and the tubular injury score was assessed. The expression of NF-κB, phosphorylated NF-κB (p-NF-κB), Nod-like receptor protein 3 (NLRP3), interleukin-1beta (IL-1β) and IL-18 in renal tissues was detected by Western blot. The expression of Toll-like receptor 4 (TLR4), NLRP3, IL-1β, TNF-α and IL-6 mRNA was determined by real-time polymerase chain reaction. Results:Compared with Sham group, the levels of serum CK-MB, LDH, Cr and BUN and renal tubule injury score were significantly increased, the expression of p-NF-κB, NLRP3, IL-1β and IL-18 was up-regulated, the expression of TLR4, NLRP3, IL-1β, TNF-α and IL-6 mRNA was up-regulated ( P<0.05), and the pathological injury to renal tissues was aggravated in I/R group. Compared with I/R group, the serum CK-MB, LDH, Cr, BUN and renal tubular injury score were significantly decreased, and the expression of p-NF-κB, NLRP3, IL-1β and and IL-18 was down-regulated, the expression of TLR4, NLRP3, IL-1β, TNF-α and IL-6 mRNA was down-regulated ( P<0.05), and the pathological injury to renal tissues was alleviated in I/R+ C23 group. Conclusions:CIRP is involved in the process of acute renal injury in a mouse model of myocardial I/R, which is associated with activation of NF-κB signaling pathway and promotion of inflammatory responses.
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Objective:To investigate the role of Caveolin (Cav-3)/extracellular signal-regulated kinase (ERK) signaling pathway in reduction of myocardial ischemia-reperfusion (I/R) injury by morphine preconditioning in rats with chronic heart failure.Methods:Clean-grade healthy adult male Sprague-Dawley rats, weighing 200-250 g, were used in this study.Chronic heart failure was induced by ligating the left anterior descending coronary artery for 6 weeks.Thirty-six Langendorff-perfused hearts with chronic heart failure were divided into 4 groups ( n=9 each) by a random number table method: myocardial I/R group (group IR), morphine preconditioning group (group MP), morphine preconditioning plus methyl-β-cyclodextrin group (group MP+ MβCD), and methyl-β-cyclodextrin group (group MβCD). Global myocardial I/R was induced by 30 min ischemia followed by 120 min reperfusion.In group MP, after 15 min of equilibration, hearts were subjected to 3 cycles of 5 min perfusion with K-H solution containing 1 μmol/L morphine for preconditioning followed by 5 min perfusion with K-H solution, 30 min in total, and after the end of treatment, hearts were subjected to 30 min ischemia followed by 120 min reperfusion.In group MP+ MβCD, hearts were perfused with K-H solution containing 200 μmol/L methyl-β-cyclodextrin at 10 min before preconditioning with morphine, and the other treatments were similar to those previously described in group MP.In group MβCD, hearts were perfused with K-H solution containing 200 μmol/L methyl-β-cyclodextrin at 40 min before ischemia, and the other treatments were similar to those previously described in group IR.At the end of 15 min of equilibration (T 0) and 5 and 10 min of reperfusion (T 1, 2), coronary outflow was collected for determination of actate dehydrogenase (LDH) activity by chemical colorimetry.Myocardial infarct size (IS) and area at risk (AAR) were measured, and IS/AAR was calculated at the end of 120 min reperfusion.Myocardial tissues of left ventricle were taken to detect the expression of Cav-3, ERK1/2 and phosphorylated ERK1/2 (p-ERK1/2) by Western blot, and p-ERK1/2/ERK1/2 ratio was calculated. Results:Compared with group IR, IS, IS/AAR and LDH activity in coronary outflow were significantly decreased, the expression of Cav-3 was up-regulated, and p-ERK1/2/ERK1/2 ratio was increased in group MP ( P<0.05). Compared with group MP, IS, IS/AAR and LDH activity in coronary outflow were significantly increased, the expression of Cav-3 was down-regulated, and p-ERK1/2/ERK1/2 ratio was decreased in group MP+ MβCD ( P<0.05). Conclusions:The mechanism by which morphine preconditioning reduces I/R injury may be related to activation of Cav-3/ERK signaling pathway in rats with chronic heart failure.
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Objective:To evaluate the role of glucagon-like peptide-1 receptor (GLP-1R) signaling pathway in sevoflurane postconditioning-induced attenuation of myocardial ischemia-reperfusion (I/R) injury in rats.Methods:Eighty SPF healthy adult male Sprague-Dawley rats, aged 8-10 weeks, weighing 300-340 g, were divided into 4 groups ( n=20 each) by a random number table method: sham operation group (group S), myocardial I/R group (group I/R), myocardial I/R plus sevoflurane postconditioning group (group ISP), and myocardial I/R plus sevoflurane postconditioning plus GLP-1R antagonist group (group ISPE). The myocardial I/R injury model was developed by ligating the left anterior descending branch of the coronary artery for 40 min followed by 2-h reperfusion in anesthetized rats.In group ISP, the rats inhaled 2.4% sevoflurane for 15 min starting from the beginning of reperfusion.In group ISPE, GLP-1R antagonist Exendin9-39 50 μg/kg (in 1 ml 0.9% normal saline) was intraperitoneally injected once a day from 28 days before development of the model, the last intraperitoneal injection was completed at 40 min before inhalation of sevoflurane, and the other treatments were the same as those previously described in group ISP.Blood samples from the abdominal aorta were collected immediately after reperfusion to determine the serum levels of creatine kinase-MB (CK-MB) and lactate dehydrogenase (LDH). Then the rats were sacrificed, and the hearts were obtained for microscopic examination of the histopathological changes of myocardial tissues (by HE staining) and the ultrastructure of cardiomyocytes (with a transmission electron microscope) for determination of the myocardial infarct size (TTC staining), expression of GLP-1R in myocardium (by immunohistochemical staining), expression of GLP-1R, cyclic adenosine monophosphate (cAMP), protein kinase A (PKA), cAMP response element-binding protein (CREB), phospho-CREB (p-CREB), B-cell lymphoma-2 (Bcl-2) and Bcl-2 associated x protein (Bax) in myocardium (by Western blot). The ratios of p-CREB/CREB and Bcl-2/Bax were calculated. Results:Compared with group S, the serum levels of CK-MB and LDH and percentage of myocardial infarct size were significantly increased, the expression of GLP-1R was up-regulated, the expression of cAMP and PKA was down-regulated, and the p-CREB/CREB ratio and Bcl-2/Bax ratio were decreased in group I/R ( P<0.05). Compared with group I/R, the serum levels of CK-MB and LDH and percentage of myocardial infarct size were significantly decreased, the expression of GLP-1R, cAMP and PKA was up-regulated, and p-CREB/CREB ratio and Bcl-2/Bax ratio were increased in group ISP ( P<0.05). Compared with group ISP, the serum levels of CK-MB and LDH and percentage of myocardial infarct size were significantly increased, the expression of GLP-1R, cAMP and PKA was down-regulated, and the p-CREB/CREB ratio and Bcl-2/Bax ratio were decreased in group ISPE ( P<0.05). Conclusions:Sevoflurane postconditioning can attenuate myocardial I/R injury by activation of GLP-1R signal pathway and inhibition of cardiomyocyte apoptosis in rats.
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Objective:To investigate the diagnostic value of electrocardiographic ST-segment changes for myocardial injury related to percutaneous coronary intervention.Methods:We included 60 patients who received percutaneous coronary intervention in Haining People's Hospital from January 2020 to February 2021 in this study. We detected serum troponin I level before and after treatment and recorded electrocardiographic ST-segment changes. Taking serum troponin I level as a reference, we divided these patients into myocardial injury and non-myocardial injury groups and analyzed the influential factors of myocardial injury.Results:Balloon inflation time and stent length were (85.6 ± 56.2) minutes and (25.2 ± 15.2) mm in the myocardial injury group, and they were (48.5 ± 39.2) minutes and (17.2 ± 8.2) mm in the non-myocardial injury group. There were no significant differences in balloon inflation time and stent length between the two groups ( t = -3.01, -2.42, both P < 0.05). The proportion of patients with electrocardiographic ST-segment changes was significantly higher in the myocardial injury group than in the non-myocardial injury group [(80.77% (21/26) vs. 5.88% (2/34), χ2= 34.95, P < 0.001). Multivariable logistic regression analysis results showed that electrocardiographic ST-segment changes were an influential factor of myocardial injury ( r = 69.25, P < 0.05). Conclusion:Electrocardiographic ST-segment changes are an independent influential factor of myocardial injury related to percutaneous coronary intervention. It can effectively judge the possibility of developing a myocardial injury and increase the safety of percutaneous coronary intervention.
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Objective:To evaluate the effects of exosomes derived from cardiac fibroblasts pretreated with sevoflurane on ventricular electrical conduction in isolated rat hearts subjected to hypothermic ischemia-reperfusion (I/R) using the multi-electrode array mapping technique.Methods:Primary cardiac fibroblasts were extracted by differential adhesion in SPF Sprague-Dawley rats of either sex.Cardiac fibroblasts of passage 2-4 were treated with 2.5% sevoflurane for 1 h, and then cultured for 24-48 h to extract exosome.SPF healthy male Sprague-Dawley rats, aged 2-3 months, weighing 280-320 g, were divided into 3 groups ( n=8 each) using a random number table method: control group (group C), I/R group and sevoflurane-pretreated cardiac fibroblast-derived exosome+ IR group (group S+ IR). Hearts were perfused for 110-min equilibration in group C. After 20 min of equilibration, the perfusion was suspended for 60 min (global ischemia) followed by 30 min of reperfusion in IR and S+ IR groups.Exosomes 1 ml (200 μg) derived from cardiac fibroblasts pretreated with sevoflurane were injected through the tail vein at 48 h before surgery in group S+ IR, and the equal volume of normal saline was injected instead in C and IR groups.The cardiac conduction velocity (CV), conduction absolute inhomogeneity (P 5-95) and inhomogeneity index (P 5-95/P 50) were obtained at 20 min of equilibration (T 0) and 15 and 30 min of reperfusion (T 1, 2) using the microelectrode array attaching to the left ventricular surface of the isolated heart. Results:Compared with group C, CV was significantly decreased and P 5-95 and P 5-95/P 50 were increased at T 1 ( P<0.05), and no significant change was found at T 2 in group S+ IR ( P>0.05), and CV was significantly decreased and P 5-95 and P 5-95/P 50 were increased at T 1, 2 in group IR ( P<0.05). Compared with group IR, CV was significantly increased and P 5-95 and P 5-95/P 50 were decreased at T 1, 2 in group S+ IR ( P<0.05). Conclusions:Exosomes derived from cardiac fibroblasts pretreated with sevoflurane can improve ventricular electrical conduction in isolated rat hearts subjected to hypothermic I/R.
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Objective:To evaluate the role of acetaldehyde dehydrogenase 2 (ALDH2) in hippocampus in memory decline after myocardial ischemia-reperfusion (I/R) in rats.Methods:Twenty-four healthy male Sprague-Dawley rats, aged 2-3 months, weighing 220-280 g, were divided into 3 groups ( n=8 each) using a random number table method: sham operation group (group S), myocardial I/R group (group I/R) and ALDH2 agonist ALDA-1 group (group ALDA-1). Myocardial I/R was induced by 30 min occlusion of left anterior descending branch of coronary artery followed by 120 min reperfusion in anesthetized animals.ALDA-1 10 mg/kg was intraperitoneally injected at 5 min before ischemia in group ALDA-1.The positioning navigation training in Morris water maze test was started from 6 days before developing the model.The spatial exploration in Morris water maze test was performed at 24 h after developing the model.The rats were sacrificed after the end of behavioral experiment, and the hippocampus was extracted for microscopic examination of the pathological changes (by hematoxylin and eosin staining) and for determination of the apoptosis index (AI) (by TUNEL staining), activity of ALDH2 (by colorimetry), contents of 4-hydroxynonenal (4-HNE) and malondialdehyde (MDA) (by enzyme-linked immunosorbent assay), and expression of ALDH2 and 4-HNE (by Western blot). Results:Compared with group S, the number of crossing the original platform was significantly decreased, the time spent in the target quadrant was shortened, the activity of ALDH2 in the hippocampus was decreased, the expression of 4-HNE was up-regulated, and the contents of 4-HNE and MDA and AI were increased in group I/R ( P<0.05). Compared with group I/R, the number of crossing the original platform was significantly increased, the time spent in the target quadrant was prolonged, the ALDH2 activity was increased, the expression of 4-HNE was down-regulated, and the contents of 4-HNE and MDA and AI were decreased in group ALDA-1 ( P<0.05). There was no significant difference in ALDH2 expression in hippocampus among the three groups ( P>0.05). Conclusions:The mechanism of memory decline developed after myocardial I/R may be related to the decrease in ALDH2 activity and promotion of accumulation of aldehydes in the hippocampus of rats.
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Objective:To evaluate the role of hypoxia-inducible factor-1α (HIF-1α)/Bcl-2/E1B 19-kDa interacting protein 3 (BNIP3) signaling pathway in dexmedetomidine-induced reduction of myocardial ischemia-reperfusion (I/R)-induced brain injury in mice.Methods:Sixty clean-grade healthy male C57BL/6 mice, aged 8-10 weeks, weighting 20-30 g, were divided into 5 groups ( n=12 each) using a random number table method: sham operation group (S group), myocardial I/R group (IR group), myocardial I/R plus dexmedetomidine group (IRD group), myocardial I/R plus HIF-1α inhibitor 2ME2 group (IR-M group), and myocardial I/R plus dexmedetomidine plus HIF-1α inhibitor 2ME2 group (IRD-M group). The myocardial I/R-induced brain injury was produced by ligating the left anterior descending coronary artery for 30 min followed by 2 h of reperfusion in anesthetized mice.Dexmedetomidine 50 μg/kg was intraperitoneally injected at 5 min before ischemia in IRD group and IRD-M group.In IR-M and IRD-M groups, 2ME2 15 mg/kg was intraperitoneally injected at 5 min before ischemia.Blood samples were collected from the thoracic aorta at 2 h of reperfusion to measure the serum S-100β protein and neuron-specific enolase (NSE) concentrations.The animals were then sacrificed, brains were removed and hippocampi were obtained for determination of the apoptosis index (by TUNEL method) and expression of HIF-1α, BNIP3, Beclin-1, microtubule-associated protein 1 light chain 3 (LC3) and phosphorylated Tau protein (p-Tau) (by Western blot) and for microscopic examination of the pathological changes in hippocampal CA1 region.LC3Ⅱ/Ⅰ ratio was calculated. Results:Compared with group S, the concentrations of serum S-100β protein and NSE and apoptosis index of hippocampal neurons were significantly increased, the expression of HIF-1α, BNIP3, Beclin-1 and p-Tau was up-regulated, LC3Ⅱ/Ⅰ ratio was increased ( P<0.05), and the pathological changes in hippocampal CA1 region were aggravated in group IR.Compared with group IR, the concentrations of serum S-100β protein and NSE and apoptosis index of hippocampal neurons were significantly decreased, the expression of HIF-1α, BNIP3 and Beclin-1 was up-regulated, the expression of p-Tau was down-regulated, and LC3Ⅱ/Ⅰ ratio was increased ( P<0.05), and the pathological changes in hippocampal CA1 region were significantly attenuated in group IRD.Compared with group IRD, the concentrations of serum S-100β protein and NSE and apoptosis index of hippocampal neurons were significantly increased, the expression of p-Tau was up-regulated, the expression of HIF-1α, BNIP3 and Beclin-1 was down-regulated, LC3Ⅱ/Ⅰ ratio was decreased ( P<0.05), and the pathological changes in hippocampal CA1 region were aggravated in IR-M and IRD-M groups. Conclusions:HIF-1α/BNIP3 signaling pathway is involved in dexmedetomidine-induced reduction of myocardial I/R-induced brain injury in mice.
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Objective:To evaluate the relationship between nuclear receptor subfamily 1, group D, member 1 (Rev-erbα) and NOD-like receptor protein 3 (NLRP3) inflammasome during myocardial ischemia-reperfusion (I/R) in diabetic rats.Methods:SPF-grade healthy male Sprague-Dawley rats, weighing 210-240 g, in which 1% streptozotocin 60 mg/kg was intraperitoneally injected to develop the model of type 1 diabetes mellitus.Eighteen non-diabetic rats were divided into 2 groups by the random number table method: non-diabetic sham operation group (NS group, n=6) and non-diabetic myocardial I/R group (NIR group, n=12). Thirty diabetic rats were divided into 3 groups by the random number table method: diabetic sham operation group (DS group, n=6), diabetic myocardial I/R group (DIR group, n=12), and diabetic myocardial I/R + Rev-erbα inhibitor SR8278 group (DIR+ SR group, n=12). Myocardial I/R model was developed by ligation of left anterior descending coronary artery for 30 min followed by reperfusion for 120 min.In DIR+ SR group, SR8278 2 mg/kg was injected via the femoral vein at 1 h before ischemia.At the end of reperfusion, blood samples from the right carotid artery were collected for determination of serum creatine kinase-MB (CK-MB), lactate dehydrogenase (LDH) and cardiac troponin I (cTnI) levels (by enzyme-linked immunosorbent assay). Then the rats were sacrificed, hearts were removed and myocardial tissues were obtained for determination of the percentage of myocardial infarct size (by TTC method) and expression of Rev-erbα, NLRP3 and IL-1β (by Western blot) and for microscopic examination of pathologic changes (by HE staining). Results:Compared with sham-operated rats, the serum concentrations of CK-MB, LDH and cTnI were significantly increased, the expression of Rev-erbα, NLRP3 and IL-1β in myocardial tissues was up-regulated ( P<0.05), and the pathological injury of myocardial tissues was obvious in myocardial I/R rats.Compared with NIR group, the percentage of myocardial infarct size and levels of serum CK-MB, LDH and cTnI were significantly increased, the expression of Rev-erb α, NLRP3 and IL-1β was up-regulated ( P<0.05), and the pathological injury of myocardial tissues was aggravated in DIR group.Compared with DIR group, the percentage of myocardial infarct size and serum CK-MB, LDH and cTnI levels were significantly decreased, the expression of Rev-erbα, NLRP3 and IL-1β was down-regulated ( P<0.05), and the pathological injury of myocardial tissues was reduced in DIR+ SR group. Conclusions:Rev-erbα can promote activation of NLRP3 inflammasome and is involved in the pathophysiological mechanism of myocardial I/R injury in diabetic rats.
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Objective:To evaluate the role of adenosine monophosphate-dependent protein kinase/p38 mitogen-activated protein kinase/nuclear factor E2-associated factor 2 (AMPK/p38 MAPK/Nrf2) pathway in myocardial ischemia-reperfusion (I/R) injury in diabetic rats.Methods:Clean-grade healthy Sprague-Dawley male rats, aged 2-3 months, weighing 220-280 g, were fed with a high fat diet, and 1% streptozotocin 50 mg/kg was intraperitoneally injected for 4 consecutive days to develop the model of diabetes mellitus.Thirty diabetic rats were divided into 3 groups ( n=10 each) using the random number table method: sham operation group (sham group), myocardial I/R group (I/R group), and AMPK inhibitor compound C+ myocardial I/R group (C+ I/R group). The model of myocardial I/R injury was developed by ligation of the left anterior descending coronary artery for 30 min followed by 120 min reperfusion.Compound C 0.5 mg/kg was injected via the caudal vein at 30 min before ischemia in C+ I/R group, while the equal volume of normal saline was given instead in Sham group and I/R group.At 120 min of reperfusion, the percentage of myocardial infarct size was calculated, the serum concentrations of creatine kinase isoenzymes (CK-MB) and lactic dehydrogenase (LDH) were determined by enzyme-linked immunosorbent assay, the levels of glutathione (GSH), superoxide dismutase (SOD) and reactive oxygen species (ROS) in myocardial tissues were measured by enzyme-linked immunosorbent assay, and the expression of AMPK, phosphorylated AMPK (p-AMPK), phosphorylated p38 MAPK (p-p38 MAPK), Nrf2 and heme oxygenase-1 (HO-1) in myocardium was determined by Western blot. Results:Compared with Sham group, the percentage of myocardial infarct size and serum CK-MB and LDH levels were significantly increased, the levels of GSH and SOD in myocardial tissues were decreased, ROS level was increased, and the expression of AMPK, p-AMPK, p-p38 MAPK, Nrf2 and HO-1 was up-regulated in I/R group ( P<0.05). Compared with I/R group, the percentage of myocardial infarct size and serum CK-MB and LDH levels were significantly increased, the levels of GSH and SOD in myocardial tissues were decreased, ROS level was increased, and the expression of AMPK, Nrf2 and HO-1 was down-regulated in C+ I/R group ( P<0.05). Conclusions:AMPK/p38 MAPK/Nrf2 signaling pathway is involved in the mechanism of endogenous antioxidant stress during myocardial I/R in diabetic rats.
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Objective:To observer the effect of electroacupuncture at "Neiguan", "Ximen" and "Hegu" acupoints of the Pericardium Meridian and observe the expression of CaMK Ⅱ mRNA and apoptosis in the myocardial ischemic rats with reperfused injury.Methods:The Wister rats were randomly divided into sham operation group, model group, Acupuncture Neiguan group, Acupuncture Ximen group and Acupuncture Hegu group, with 10 rats in each group. Exceptthe sham operation group, the othergroups were all ligated with the left anterior descending branch of the coronary artery. Before ligating the coronary artery, electroacupuncture was performed at "Neiguan", "Ximen" and "Hegu" points for 20 minutes respectively. After the ligation for 40 minutes, electroacupuncture was performed at the above points for 20 minutes and then restore coronary perfusion for 60 minutes. The ECG changes of rats were recorded. The level of CaMK Ⅱ mRNA was detected by RT-PCR and the apoptosis rate of cardiomyocytes was detected by TUNEL. The correlation between the expression rate of CaMK Ⅱ mRNA and the apoptosis rate of cardiomyocytes was analyzed according to the pearson correlation.Results:At 20, 40 and 60 min after the ligation of coronary artery and 30 and 60 min after the loosening of coronary artery, compared with the model group and Acupuncture Hegu group, the ST segment difference of Acupuncture Neiguan group and Acupuncture Ximen group was decreased ( P<0.01); The levels of CaMK Ⅱ mRNA (0.483 ± 0.050, 0.432 ± 0.079 vs. 0.935 ± 0.109) in Acupuncture Neiguan group and Acupuncture Ximen group were significantly decreased ( P<0.01). The apoptosis rate of cardiomyocytes (10.86% ± 2.17%, 9.66% ± 4.09% vs. 36.22% ± 1.69%) significantly decreased ( P<0.01). Conclusions:There is a positive correlation between CaMK Ⅱ mRNA level and cardiomyocyte apoptosis during myocardial ischemia-reperfusion. Acupuncture can effectively reduce CaMK Ⅱ mRNA level and cardiomyocyte apoptosis rate and protect cardiomyocytes.
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Objective:To investigate the role of receptor-interacting protein kinse3 (RIPK3)-mediated necroptosis in diabetic mellitus-caused abolition of cardioprotection induced by sevoflurane postconditioning in rats.Methods:Eighty rats with diabetes mellitus, aged 4-5 weeks, weighing 90-100 g, were divided into 4 groups ( n=20 each) using a random number table method: sham operation group (group Sham), myocardial ischemia-reperfusion (I/R) group (group I/R), sevoflurane postconditioning group (group SP) and sevoflurane postconditiong plus RIPK3 inhibitor GSK-872 group (group GSK). Myocardial I/R was induced by 40 min occlusion of the left anterior descending branch of the coronary artery followed by 120 min reperfusion.In group SP, 2.4% sevoflurane was inhaled for 15 min at the beginning of reperfusion.In group GSK, GSK-872 3.3 mg/kg (dissolved in normal saline) was intraperitoneally injected at 24 and 2 h before surgery, and the other treatments were similar to those previously described in group SP.After 120 min of reperfusion, blood samples from the abdominal aorta were collected for determination of concentrations of serum lactate dehydrogenase (LDH) and creatine kinase-MB (CK-MB). Myocardial tissues were taken for determination of percentage of myocardial infarct size (by TTC staining) and expression of RIPK3, phospho-Ca 2+ -calmodulin-dependent protein kinase Ⅱ (p-CaMKⅡ) and phospho-mixed lineage kinase domain-like protein (p-MLKL) (by Western blot), and the ultrastructure of myocardium was observed by transmission electron microscopy. Results:Compared with group Sham, the serum LDH and CK-MB concentrations and percentage of myocardial infarct size were significantly increased, the expression of RIPK3, p-MLKL and p-CaMKⅡ in myocardial tissues was up-regulated ( P<0.05), and the damage to cardiomyocytes was severe in group I/R.Compared with group I/R, no significant change was found in the parameters mentioned above in group SP ( P>0.05). Compared with group SP, the serum LDH and CK-MB concentrations and percentage of myocardial infarct size were significantly decreased, the expression of RIPK3, p-MLKL and p-CaMKⅡ in myocardial tissues was down-regulated ( P<0.05), and the damage to cardiomyocytes was reduced in group GSK. Conclusion:The mechanism of diabetic mellitus-caused abolition of cardioprotection induced by sevoflurane postconditioning is related to excessive activation of RIPK3-mediated necroptosis in rats.
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Objective:To evaluate the relationship between the mitochondrial mechanism of diabetic mellitus-caused abolition of cardioprotection induced by ischemia postconditioning (IPO) and succinate dehydrogenase (SDH) in rats.Methods:Thirty-six SPF male non-diabetic Sprague-Dawley rats, aged 16-20 weeks, weighing about 300 g, were divided into 3 groups ( n=12 each) using a random number table method: sham operation group (ND+ Sham group), ischemia-reperfusion (I/R) group (ND+ I/R group) and IPO group (ND+ IPO group). Seventy-two rats with diabetes mellitus were divided into 6 groups ( n=12 each) using a random number table method: sham operation group (DM+ Sham group), I/R group (DM+ I/R group), DM+ IPO group, sham operation+ dimethyl malonate group (group DM+ Sham+ Dme), I/R+ dimethyl malonate group (group DM+ I/R + Dme) and IPO+ dimethyl malonate group (group DM+ IPO+ Dme). The model of cardiopulmonary bypass (CPB) was established, and the model of total I/R injury was induced by ligating the ascending aorta for 30 min followed by 60 min of reperfusion.The animals underwent 3 cycles of 30-s reperfusion followed by 30-s ischemia starting from the onset of reperfusion in each IPO group.In each Dme group, dimethyl malonate was infused through the tail vein at a rate of 4 mg· kg -1·min -1 for 40 min starting from the beginning of CPB.At the end of reperfusion, the myocardial tissues were taken for measurement of mitochondrial respiratory control ratio (RCR) (by the Lufthansa electrode method), mitochondrial membrane potential (MMP) (by the JC-1 method) and the opening of mitochondrial permeability transition pore (mPTP) (by absorptiometry) and for determination of the activity of reactive oxygen species (ROS) (with the fluorescent probe), succinate dehydrogenase (SDH) (using spectrophotometric method) and the contents of succinic acid and fumarate. Results:Compared with ND+ Sham group, the activities of SDH and ROS, opening of mPTP and content of fumarate were significantly increased, and MMP, RCR and succinic acid content were decreased in ND+ I/R ( P<0.05). Compared with group ND+ I/R, the activities of SDH and ROS, opening of mPTP and content of fumarate were significantly decreased, and MMP, RCR and succinic acid content were increased in ND+ IPO ( P<0.05). Compared with group DM+ Sham, the activities of SDH and ROS, opening of mPTP and content of fumarate were significantly increased, and MMP, RCR and succinic acid content were decreased in group DM+ I/R ( P<0.05). Compared with group DM+ I/R, no significant change was found in the parameters mentioned above in group DM+ IPO ( P>0.05). Compared with group DM+ IPO, the activities of SDH and ROS, opening of mPTP and content of fumarate were significantly decreased, and MMP, RCR and succinic acid content were increased in group DM+ IPO+ Dme ( P<0.05). Compared with group DM+ I/R+ Dme, the activities of SDH and ROS, opening of mPTP and content of fumarate were significantly decreased, and MMP, RCR and succinic acid content were increased in group DM+ IPO+ Dme ( P<0.05). Conclusion:The mitochondrial mechanism of diabetic mellitus-caused abolition of cardioprotection induced by IPO may be related to the enhancement of SDH activity in rats.
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Objective:To evaluate the effect of activating adenosine A2B receptors on autophagy during myocardial ischemia-reperfusion (I/R) and the role of phosphatidylinositol 3-kinase/serine/threonine protein kinase (PI3K/Akt) signaling pathway in rats.Methods:Forty-eight clean-grade healthy male Sprague-Dawley rats, weighing 220-280 g, were divided into 4 groups ( n=12 each) using a random number table method: sham operation group (group Sham), myocardial I/R group (group I/R), adenosine A2B receptor agonist BAY 60-6583 group (group BAY) and BAY 60-6583+ PI3K inhibitor LY 294002 group (group BAY+ LY). Myocardial I/R was induced by occlusion of the anterior descending branch of the left coronary artery for 30 min followed by 120-min reperfusion.BAY 60-6583 1 mg/kg was intraperitoneally injected at 5 min before reperfusion in group BAY.BAY 60-6583 1 mg/kg was intraperitoneally injected at 5 min before reperfusion and LY 294002 10 mg/kg was intraperitoneally injected at 10 min before reperfusion in group BAY+ LY.Blood samples were obtained at the end of reperfusion for determination of concentrations of lactate dehydrogenase (LDH) and creatine kinase-MB (CK-MB) in serum (by enzyme-linked immunosorbent assay). The animals were sacrificed, and myocardial tissues were obtained for measurement of the percentage of myocardial infarct size (by Evan Blue and TTC double-staining) and for determination of the expression of microtubule-associated protein 1 light chain 3 (LC3Ⅰ), LC3Ⅱ, Beclin-1 and phosphorylated Akt (p-Akt) (by Western blot). The ratio of LC3Ⅱ/LC3Ⅰ was calculated. Results:Compared with group Sham, the serum LDH and CK-MB concentrations and percentage of myocardial infarct size were significantly increased, the expression of p-Akt was down-regulated, the expression of Beclin-1 and LC3Ⅱ was up-regulated, and the ratio of LC3Ⅱ/LC3Ⅰ was increased in group I/R ( P<0.05). Compared with group I/R, the concentrations of serum LDH, CK-MB and percentage of myocardial infarct size were significantly decreased, the expression of p-Akt was up-regulated, the expression of Beclin-1 and LC3Ⅱ was down-regulated, and the ratio of LC3Ⅱ/LC3Ⅰ was decreased in the group BAY ( P<0.05), and no significant change was found in the parameters mentioned above in group BAY+ LY ( P>0.05). Compared with group BAY, the concentrations of serum LDH, CK-MB and percentage of myocardial infarct size were significantly increased, the expression of p-Akt was down-regulated, the expression of Beclin-1 and LC3Ⅱ was up-regulated and the ratio of LC3Ⅱ/LC3Ⅰ was increased in group BAY+ LY ( P<0.05). Conclusion:Activating adenosine A2B receptors can decrease autophagy of myocardial cells during myocardial I/R injury, and the mechanism may be related to activating PI3K/Akt signaling pathway in rats.