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Objective:To evaluate the role of autophagy in reduction of high glucose and hypoxia-reoxygenation (HG+ H/R) injury to isolated cardiomyocytes by dexmedetomidine in rats.Methods:The normally cultured rat H9c2 cardiomyocytes at the logarithmic growth phase were seeded in 6-well plates at a density of 1×10 6 cells/ml and divided into 4 groups ( n=15 each) using a random number table method: control group (group C), group HG+ H/R, dexmedetomidine group (group DEX) and dexmedetomidine+ autophagy inhibitor 3-methylpurine group (group 3-MA). The cells were incubated in culture medium with 1% fetal bovine serum + 1% double antibody for 24 h when the cell density reached 50%.To establish HG+ H/R injury model, the cardiomyocytes were cultured in high-glucose culture medium (glucose concentration of 33 mmol/L) for 24 h, and then incubated in a 37 ℃ incubator (95% N 2+ 5%CO 2) for 4 h followed by reoxygenation (90%O 2+ 10%CO 2) for 2 h. Dexmedetomidine was added until the final concentration reached 5 μmol/L at 1 h before hypoxia in DEX and 3-MA groups, and 3-MA was added until the final concentration reached 5 μmol/L at 1 h of incubation with dexmedetomidine.At 2 h after reoxygenation, the cell viability was recorded by the cell counting kit-8 assay, lactate dehydrogenase (LDH) activity was detected by LDH kit, the expression of autophagy-related protein LC3, P62 and Beclin-1 was detected by Western Blot, the ratio of LC3Ⅱ/LC3Ⅰwas calculated, and the expression of P62 and Beclin-1 mRNA was detected by real-time polymerase chain reaction. Results:Compared with group C, the cell viability was significantly decreased in HG+ H/R, DEX and 3-MA groups, LDH activity in the supernatant was increased and expression of P62 was decreased in HG+ H/R and 3-MA groups, ratio of LC3Ⅱ/LC3Ⅰwas decreased in group 3-MA, and the expression of Beclin-1 was down-regulated in group HG+ H/R ( P<0.05). Compared with HG+ H/R group, LDH activity in the supernatant was significantly decreased, expression of Beclin-1, P62 and its mRNA was up-regulated, and ratio of LC3Ⅱ/LC3Ⅰwas increased in DEX group, and LDH activity in the supernatant was increased in group 3-MA ( P<0.05). Compared with DEX group, cell viability were decreased, LDH activity in the supernatant was increased, Beclin-1, P62 and its mRNA was down-regulated, and ratio of LC3Ⅱ/ LC3Ⅰwas decreased in group 3-MA ( P<0.05). Conclusion:Autophagy is involved in the reduction of HG+ H/R injury to isolated cardiomyocytes by dexmedetomidine in rats.
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Objective:To evaluate the effect of TBK1 overexpression on hypoxia-reoxygenation (H/R) injury in isolated mouse cardiomyocytes subjected to high glucose and the relationship with mitochondrial autophagy.Methods:Normally cultured log-phase HL-1 mouse cardiomyocytes were inoculated in a 6-well plate at a density of 1×10 6 cells/ml and were divided into 4 groups ( n=10 each) using a random number table method: control group (group C), high glucose group (group HG), high glucose and H/R group (group HG+ H/R), and TBK1 overexpression group (group TBK1). The cells were incubated in culture medium with 1% fetal bovine serum and 1% double antibody for 24 h when the cell density reached 50%.When the cell density reached 80%, pcDNA3.1 (+ ) was used as a vector to achieve TBK1 overexpression.The cells were cultured with high glucose medium (33 mmol/L) for 24 h, exposed to 94% N 2+ 5% CO 2+ 1% O 2 for 24 h in an incubator at 37℃ followed by 12 h reoxygenation in an incubator containing 5% CO 2 at 37°C to establish the model of H/R injury to cardiomyocytes subjected to high glucose.After reoxygenation, CCK-8 assay was used to detect cell viability, the activity of lactic dehydrogenase (LDH) in supernatant was detected using LDH kit, mitochondrial contents were determined using Mito-Tracter green fluorescent probe, and the expression of TBK1 and mitophagy-related proteins PINK1, Parkin, LC3B and P62 was detected by Western blot. Results:Compared with group C, the cell viability was significantly decreased, the activity of LDH in supernatant was increased, mitochondrial contents were decreased, the expression of TBK1, PINK1, Parkin and LC3B was down-regulated, and the expression of P62 was up-regulated in HG group and HG+ H/R group ( P<0.05). Compared with group HG, the cell viability was significantly decreased, the activity of LDH in supernatant was increased, mitochondrial contents were decreased, the expression of TBK1, PINK1, Parkin and LC3B was down-regulated, and the expression of P62 was up-regulated in group HG+ H/R ( P<0.05). Compared with group HG+ H/R, the the cell viability was significantly increased, the activity of LDH in supernatant was decreased, mitochondrial contents were increased, the expression of TBK1, PINK1, Parkin and LC3B was up-regulated, and the expression of P62 was down-regulated in group TBK1 ( P<0.05). Conclusion:The mechanism by which TBK1 overexpression reduces the H/R injury is related to restoring mitophagy in isolated mouse cardiomyocytes subjected to high glucose.
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Objective:To evaluate the role of Notch1/hairy and enhancer of split homolog1(Hes1) signaling pathway in high glucose and hypoxia-reoxygenation (H/R) injury to cardiomyocytes.Methods:H9c2 cardiomyocytes were cultured in low-glucose DMEM culture medium supplemented with 10% fetal bovine serum.The cells were divided into 6 groups ( n=12 each) using a random number table method: control group (group C), H/R group, H/R+ Jagged-1 group (group H/R+ J), high glucose group (group HG), high glucose+ H/R group (group HG+ H/R) and high glucose+ H/R+ Jagged-1 group (group HG+ H/R+ J). The cells were incubated in low-glucose culture medium for 72 h in group C. After incubated in low-glucose culture medium for 72 h, the cells were exposed to 24-h hypoxia in an incubator filled with 95% N 2-5% CO 2 at 37℃, immediately followed by 6-h reoxygenation in an incubator filled with 95% O 2-5% CO 2 at 37℃ in group H/R.In group H/R+ J, Jagged-1 (Notch1/Hes1 signaling pathway specific activator) 5μg/ml was added to low-glucose culture medium and the cells were incubated for 72h before H/R.In group HG, H9c2 cardiomyocytes were incubated in high-glucose culture medium containing 33 mmol/L glucose for 72 h. In group HG+ H/R, the cells were incubated in high-glucose medium for 72 h before H/R.In group HG+ H/R+ J, Jagged-1 5μg/ml was added to high-glucose culture medium, and the cells were incubated for 72 h before H/R.At 6 h of reoxygenation, the supernatant of the culture medium was collected for detection of the activities of superoxide dismutase (SOD) and lactic dehydrogenase (LDH), the cell viability (by CCK-8 assay) and the cell apoptosis rate (by flow cytometry) and for determination of expression of Notch1, Hes1 and c-caspase-3 (by Western blot). Results:Compared with group C, the cell survival rate and SOD activity were significantly decreased, and apoptosis rate and LDH activity were increased in H/R, H/R+ J and HG groups, expression of Notch1, Hes1 and c-caspase-3 was up-regulated in H/R and H/R+ J groups, and the expression of Notch1 and Hes1 was down-regulated and c-caspase-3 expression was up-regulated in group HG ( P<0.05). Compared with group H/R, the cell survival rate and SOD activity was significantly increased, apoptosis rate and LDH activity were decreased, expression of Notch1 and Hes1 was up-regulated, and c-caspase-3 expression was down-regulated in group H/R+ J, and the cell survival rate and SOD activity were significantly decreased, apoptosis rate and LDH activity were increased, expression of Notch1 and Hes1 was down-regulated, and c-caspase-3 expression was up-regulated in group HG+ H/R ( P<0.05). Compared with group HG, the cell survival rate and SOD activity were significantly decreased, and apoptosis rate and LDH activity were increased in HG+ H/R and HG+ H/R+ J groups ( P<0.05), and expression of Notch1 and Hes1 was down-regulated, and c-caspase-3 expression was up-regulated in group HG+ H/R ( P<0.05). Compared with group HG+ H/R, the cell survival rate and SOD activity were significantly increased, apoptosis rate and LDH activity were decreased, expression of Notch1 and Hes1 was up-regulated, and c-caspase-3 expression was down-regulated in group HG+ H/R+ J ( P<0.05). Compared with group H/R+ J, the cell survival rate and SOD activity were significantly decreased, apoptosis rate and LDH activity were increased, expression of Notch1 and Hes1 was down-regulated, and c-caspase-3 expression was up-regulated in group HG+ H/R+ J ( P<0.05). Conclusion:Activation of Notch1/Hes1 signaling pathway is the endogenous protective mechanism of high glucose and H/R injury to cardiomyocytes.
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Objective:To evaluate the role of nuclear factor E2-related factor 2 (NRF2) in myocardial ischemia-reperfusion (I/R) injury and the relationship with ferroptosis in diabetic rats.Methods:Forty-eight SPF healthy adult male Sprague-Dawley rats, aged 6-8 weeks, weighing 200-220 g, were divided into 5 groups by a random number table method: sham operation group (group S, n=6), myocardial I/R group (group NIR, n=12), diabetes mellitus+ sham operation group (group DS, n=6), diabetes mellitus+ myocardial I/R group (group DIR, n=12) and diabetes mellitus+ myocardial I/R+ NRF2 agonist sulforaphane group (group DIR+ SFN, n=12). Type 1 diabetes mellitus was induced by intraperitoneal injection of 1% streptozotocin-citrate buffer 60 mg/kg.Sulforaphane 500 μg·kg -1·d -1 was injected intraperitoneally before ischemia for 3 consecutive days in group DIR+ SFN.At the 8th week after establishing the model, myocardial I/R was produced by occlusion of the anterior descending branch of the left coronary artery for 30 min followed by reperfusion.At 2 h of reperfusion, the left ventricular systolic pressure (LVSP), HR, and the maximum rate of increase and decrease of left ventricular systolic pressure (±dp/dt max) were recorded.Blood samples were taken from the carotid artery and the animals were then sacrificed for determination of concentration of cardiac troponin I (cTnI) in serum (using enzyme-linked immunosorbent assay), myocardial Fe 2+ and malondialdehyde (MDA) contents, superoxide dismutase (SOD) activity (by colorimetry) and myocardial infarct size (using TTC) and for determination of expression of NRF2, ferroportin1 (FPN1) and acyl-CoA synthetase long-chain family member 4 (ACSL4) (by Western blot), and the pathological changes of lung tissues were observed by hematoxylin-eosin staining. Results:Compared with group S, LVSP, HR, and ±dp/dt max were significantly decreased, serum cTnI concentration and myocardial Fe 2+ and MDA contents were increased, SOD activity was decreased, expression of ACSL4 was up-regulated and expression of NRF2 and FPN1 was down-regulated in group NIR ( P<0.05). Compared with group DS, LVSP, HR, and ±dp/dt max were significantly decreased, serum cTnI concentration and myocardial Fe 2+ and MDA contents were increased, SOD activity was decreased, expression of ACSL4 was up-regulated and expression of NRF2 and FPN1 was down-regulated in group DIR ( P<0.05). Compared with group NIR, LVSP, HR, and ±dp/dt max were significantly decreased, serum cTnI concentration and myocardial Fe 2+ and MDA contents were increased, SOD activity was decreased, myocardial infarct size was increased, expression of ACSL4 was up-regulated and expression of NRF2 and FPN1 was down-regulated in group DIR ( P<0.05). Compared with group DIR, LVSP, HR, and ±dp/dt max were significantly increased, serum cTnI concentration and myocardial Fe 2+ and MDA contents were decreased, SOD activity was increased, myocardial infarct size was decreased, expression of ACSL4 was down-regulated and expression of NRF2 and FPN1 was up-regulated in group DIR+ SFN ( P<0.05). Conclusion:NRF2 is involved in the process of myocardial I/R injury, which is related to promoting ferroptosis in diabetic rats
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Objective:To evaluate the relationship between silence information regulator 1 (SIRT1) and signal transducers and activators of transcription 3 (STAT3) acetylation during high glucose-induced cardiac microvascular endothelial cell injury.Methods:Cardiac microvascular endothelial cells of Sprague-Dawley rats were cultured.The cells at the logarithmic growth phase were selected and divided into 3 groups ( n=24 each) using a random number table method: control group (C group), high glucose group (HG group) and high glucose+ SIRT1 agonist SRT1720 group (HG+ SRT group). The cardiac microvascular endothelial cells were seeded in a 6- or 96-well cell culture plate at a density of 2×10 5 cells/ml.When the cell density reached 50%, the culture medium was then replaced with high-glucose (glucose 33 mmol/L) DMEM culture medium containing with 10% fetal bovine serum and 1% double antibody in HG and HG+ SRT groups.In group HG+ SRT, 20 μmol/L SRT1720 was added simultaneously, and the cells were cultured at 37 ℃ in an incubator with 5% CO 2 for 24 h. The cell viability was determined by CCK-8 assay, the activity of superoxide dismutase (SOD) was detected using a spectrophotometer, the levels of lactic dehydrogenase (LDH), interleukin-6 (IL-6) and tumor necrosis factor-β (TNF-β) in the supernatant were detected by enzyme-linked immunosorbent assay, and the expression of SIRT1, acetylated STAT3 (ac-STAT3) and phosphorylated STAT3 (p-STAT3) was determined by Western blot. Results:Compared with C group, the cell viability and SOD activity were significantly decreased, levels of LDH, IL-6 and TNF-β in the supernatant were increased, expression of SIRT1 was down-regulated, and expression of ac-STAT3 and p-STAT3 was up-regulated in group HG and group HG+ SRT ( P<0.05). Compared with group HG, the cell viability and SOD activity were significantly increased, levels of LDH, IL-6 and TNF-β in the supernatant were decreased, expression of SIRT1 was up-regulated, and expression of ac-STAT3 and p-STAT3 was down-regulated in group HG+ SRT ( P<0.05). Conclusion:SIRT1 can alleviate high glucose-induced cardiac microvascular endothelial cell injury by promoting STAT3 deacetylation.
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Objective:To evaluate the role of phosphoglycerate mutase 5 (phosphoglycerate mutase family member 5, PGAM5) in myocardial ischemia-reperfusion (I/R) injury in diabetic rats and the relationship with mitochondrial quality.Methods:SPF healthy male Sprague-Dawley rats, aged 6-8 weeks, weighing 200-220 g, were used in this study.Type 1 diabetes mellitus was induced by 1% streptozotocin diluted in citrate buffer solution 60 mg/kg.The rats were continuously fed for 8 weeks after successful establishment of the model.Seventy-two rats with type 1 diabetes mellitus were divided into 4 groups ( n=18 each) by a random number table method: diabetic sham operation group (DS group), diabetic myocardial I/R group (DIR group), diabetic myocardial I/R plus AAV9-PGAM5 shRNA group (DIR+ PGAM5 shRNA group), and diabetic myocardial I/R plus AAV9-GFP group (DIR+ GFP group). The myocardial I/R model was established by ligation of the left anterior descending coronary artery for 30 min followed by reperfusion for 2 h starting from 8 weeks after establishment of type 1 diabetes mellitus model.AAV9-PGAM5 shRNA and AAV9-GFP 2×10 12 μg/kg were slowly injected via tail vein 3 weeks before ischemia.In group AAV9-PGAM5 shRNA, left ventricular systolic pressure (LVSP) and the maximum rate of increase or decrease in left ventricular systolic pressure (±dp/dt max) were monitored and recorded at the end of reperfusion, and then blood samples from the the right carotid artery were collected for determination of serum troponin Ⅰ(cTnI), creatine kinase-MB (CK-MB) and lactate dehydrogenase (LDH) levels (by enzyme-linked immunosorbent assay). The animals were sacrificed and hearts were obtained for determination of myocardial infarct size (by Evans Blue plus TTC double staining method) and expression of PGAM5, autophagy-related proteins (LC3B, p62), dynamin-related protein 1 (Drp1), and mitochondrial autophagy receptor protein (FUNDC1) (by Western blot) and for microscopic examination of pathological changes of myocardial tissues (by HE staining). Results:Compared with group DS, the LVSP and ±dp/dt max were significantly decreased, the serum levels of cTnI, CK-MB and LDH were increased, myocardial infarct size was increased, the expression of PGAM5, LC3B, Drp1 and FUNDC1 was up-regulated, and the expression of p62 was down-regulated in group DIR and group DIR+ GFP ( P<0.05). Compared with group DIR, LVSP and ±dp/dt max were significantly increased, the serum levels of cTnI, CK-MB and LDH were decreased, myocardial infarct size was decreased, the expression of PGAM5, LC3B, Drp1 and FUNDC1 was down-regulated, and the expression of p62 was up-regulated in group DIR+ PGAM5 shRNA ( P<0.05), and no significant change was found in the parameters mentioned above in group DIR+ GFP ( P>0.05). Conclusion:PGAM5 is involved in the myocardial I/R injury in diabetic rats, which is related to the reduction of mitochondrial quality.
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Objective To evaluate the role of autophagy in Parkin over-expression-induced reduction of cardiac hypertrophy in diabetic rats.Methods Thirty-two healthy SPF male Sprague-Dawley rats,aged 2 months,weighing 200-230 g,were divided into 4 groups (n =8 each) using a random number table method:non-diabetes mellitus (DM) group (group Non-DM),DM group,DM plus AAV9-CMV-Parkin group (group DM+P) and DM puls AAV9-CMV-Parkin puls autophagy inhibitor 3-methyladenine (3-MA) group (group DM+P+MA).DM was induced by intraperitoneal streptozotocin (STZ) 60 mg/kg and confirmed by blood glucose level ＞16.7 mmol/L,and Parkin overexpression was achieved with adeno-associated virus serotype 9 as a vector.AAV9-CMV-Parkin 1 × 1012 mg/kg was injected into the tail vein at 3 weeks after STZ injection in group DM+P.In group DM+P+MA,AAV9-CMV-Parkin 1× 1012 mg/kg was injected into the tail vein at 3 weeks after STZ injection,and 3 weeks later 3-MA 15 mg/kg was injected into the tail vein,once a week for 6 weeks in total.Cardiac diastolic and systolic function was detected using Bmode ultrasonography.Cardiomyocytes were obtained for microscopic examination of the cross-sectional area (with a light microscope) and for determination of the expression of microtubule-associated protein 1 light chain 3,P62 and Parkin.Results Compared with group Non-DM,the cross-sectional area of cardiomyocytes was significantly increased,and the diastolic and systolic function was decreased in DM group (P＜0.05).Compared with group DM,the cross-sectional area of cardiomyocytes was significantly decreased,the diastolic and systolic function was improved,the expression of microtubule-associated protein 1 light chain 3 and Parkin in myocardial tissues was up-regulated,and the expression of P62 was down-regulated in group DM+P (P＜0.05).Compared with group MD+P,the cross-sectional area of cardiomyocytes was significantly increased,the diastolic and systolic function was decreased,the expression of microtubule-associated protein 1 light chain 3 was down-regulated,and the expression of P62 was up-regulated in group DM+P+MA (P＜0.05) Conclusion Autophagy is involved in Parkin over-expression-induced reduction of cardiac hypertrophy in diabetic rats.
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Objective To evaluate the effects of different concentrations of remifentanil on myocardial monophasic action potential (MAP) in isolated rabbit hearts.Methods Adult rabbits of both sexes,weighing 2.0-2.5 kg,were used in the study.Their hearts were excised,and retrogradely perfused with oxygenated K-H solution saturated with 95％O2-5％CO2 at 37 ℃ in a Langendorff apparatus.Twenty-four isolated hearts were randomly divided into 4 groups (n =6 each) using a random number table:control group (group C) and 3 different concentrations of remifentanil groups (group R1-3).After 15 min of stabilization,K-H solution was continuously perfused for 60 min in group C,and K-H solution containing 12,25 and 50 ng/ml remifentanil was continuously perfused for 60 min in R1,R2 and R3 groups,respectively.At 15 min of stabilization,and 15,30 and 60 min of perfusion with K-H solution,the heart rate,and the maximal velocity and amplitude of the MAP in the three layers of the left ventricular anterior wall were recorded,and the action potential duration at 90％ repolarization and transmural dispersion of repolarization (TDR) were calculated.Results Compared with group C,the heart rate was significantly decreased,and the action potential duration at 90％ repolarization and TDR were significantly prolonged at 15,30 and 60 min of perfusion in R1-3 groups (P＜0.05).Compared with C and R1 groups,the maximal velocity and amplitude of MAP were significantly decreased at 15,30 and 60 min of perfusion in R2 and R3 groups (P＜0.05).Conclusion Low-concentration remifentanil induces heart block through increasing TDR,however,high-concentration remifentanil induces heart block through inhibiting myocardial MAP depolarization and increasing TDR in the isolated rabbit hearts.
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Objective To evaluate the effects of different concentrations of remifentanil on the expression and distribution of gap junction protein connexin 43 (Cx43) in the cardiomyocytes of rabbits.Methods Healthy adult rabbits of both sexes,weighing 2.0-2.5 kg,were anesthetized with pentobarbital sodium.Their hearts were rapidly excised and retrogradely perfused in a Langendorff apparatus with K-H solution saturated with 95％ O2-5％ CO2 at 37 ℃.After 15 min of stabilization with K-H solution,the 24 isolated hearts were randomly divided into 4 groups (n =6 each) using a random number table:control group (group C),and low,medium and high concentrations of remifentanil groups (R1-3 groups).The hearts were continuously perfused with K-H solution at 37 ℃ in group C.The hearts were perfused for 60 min with K-H solution containing remifentanil 12,25 and 50 ng/ml in R1-3 groups,respectively.The myocardial specimens were then obtained from the anterior wall of the left ventricle for detection of the expression and distribution of Cx43 by Western blot and immunohistochemistry,respectively.Results The expression of Cx43 was gradually down-regulated in C and R1-3 groups in turn (P＜0.05).Compared with group C,there was a tendency for the proteins localized at end-to-end contact sites of ventricular cardiomyocytes to localize at side-to-side contact sites in R1-3 groups,and the distribution was messy in R1-3 groups.Conclusion Remifentanil dose-dependently down-regulates the expression of Cx43 and changes the distribution of Cx43,which may be one of the mechanisms of remifentanil-induced arrhythmia in rabbits.
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Objective To evaluate the accuracy of contrast enhanced ultrasonography (CEUS) in determining the depth of myometrial invasion in endometrial carcinoma in stage Ⅰ.Methods Seventy-six patients previously diagnosed of endometrial carcinoma by curettage of uterine underwent transabdominal sonography (TAS) and CEUS to assess myometrial invasion,among which 48 patients proved to endometrial carcinoma in stage Ⅰ after total abdominal hysterectomy and bilateral salpingo-oophorectomy were studied.The findings of TAS and CEUS to determine endometrial carcinoma IA (no myometrial involvement or invasion of the inner half of the myometrium) and IB( invasion of the outer half of the myometrium) were compared with pathology after abdominal hysterectomy.Results Twenty one tumours (43.75%,21/48) were enhanced earlier than or simultaneously as myometrium and cervix,among which 12 cases were IA stages,while 9 cases were IB stages (P0.05).The sensitivity,specificity,positive predictive value,negative predictive value and accuracy of TAS and CEUS in diagnosing endometrial carcinoma in IB were 61.25% vs 69.23%,77.14% vs 85.71%,50.00% vs 64.28%,72.92% vs 88.23%,72.92% vs 81.25% respectively.Conclusions CEUS is not superior to TAS in detecting deep invasion of endometrial carcinoma in stage Ⅰ.
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Objectlve To investigate the value of basic and contrast-enhanced ultrasound in the diagnosis of superficial cervical lymph nodes.Methods Five hundred and forty-five cases of superficial cervical lymph nodes were sacned by basic ultrasound,in which 52 cases were also scaned by contrast-enhanced ultrasound.All cases were performed ultrasound-guided biopsy.Lymph nodes were divided into benign group and malignant group according to pathology reports.The differences of the two groups were analysed,and statistical analysis was performed.Results Two hundred and thirty cases were benign,315 cases were malignant.S/L(P＜0.01),RI(P＜0.01),vascular pattern(P＜0.01)and contrast enhancement pattern(P＜0.01)between benign and malignant group showed statistical significant differences,while no statistical difference in coefficient correlation of the time-intensity curve between the two groups was found.Conclusions A combination of basic and contrastenhanced ultrasound can significantly enhance the ability to identify malignant lymph nodes from benign lymph nodes.