Diabetic cardiomyopathy (DCM) is a major cause of mortality in diabetic patients, with impaired mitophagy contributing its pathogenesis. Sirtuin 3 (SIRT3) and caveolin-3 (Cav-3) are protective proteins involved in mitophagy, although their precise mechanisms remain unclear. This study investigated the interplay between SIRT3, Cav-3, and mitophagy in DCM. We found that the diabetic C57BL/6 mice exhibited impaired cardiac structure and function, accompanied by reduced mitophagy and decreased expression of SIRT3 and Cav-3. Cav-3 KO mice with diabetes showed further worsened cardiac dysfunction and mitophagy impairment without further affecting SIRT3 expression. In cultured H9C2 cardiomyocytes, both SIRT3 siRNA and Cav-3 siRNA exacerbated high glucose (HG)-induced cardiomyocyte damage and reduced mitophagy occurrence. Interestingly, SIRT3 siRNA significantly decreased Cav-3 expression, but vice not. Additionally, Cav-3 overexpression rescued HG-induced cardiomyocyte injury and mitophagy impairment without affecting SIRT3 expression. Collectively, our findings suggest that hyperglycemia-induced SIRT3 suppression contributes to DCM by impairing Cav-3-mediated mitophagy.

Myocardial ischemia/reperfusion (I/R) injury is a major global health problem with high rates of mortality and disability, which is more severe in patients with diabetes. Substantial researches have documented that diabetic myocardium are more susceptible to I/R injury, but many current intervention strategies against myocardial I/R injury have limited effectiveness in diabetic hearts. Caveolin-3 (Cav-3) is the signature protein of caveolae and serves as a signal integration and transduction platform in the plasma membrane of cardiomyocytes, which plays a vital role in myocardial functions, metabolism and protection of multiple conditioning strategies against I/R injury. Nevertheless, numerous studies have revealed that the expression of Cav-3 is impaired in diabetic hearts, which contributes to increased vulnerability of myocardium to I/R injury and resistance to protective conditioning strategies. In this review, we outline the basic structure and function of Cav-3, emphatically present the unique role of Cav-3 as a signal integration and transduction element in diabetic myocardial I/R injury and discuss its therapeutic perspective in strategies against myocardial I/R injury in diabetes.

Due to changes in dietary structures, population aging, and the exacerbation of metabolic risk factors, the incidence of cardiovascular disease continues to rise annually, posing a significant health burden worldwide. Cell death plays a crucial role in the onset and progression of cardiovascular diseases. As a regulated endpoint encountered by cells under adverse stress conditions, the execution of necroptosis is regulated by classicalpathways, the calmodulin-dependent protein kinases (CaMK) pathway, and mitochondria-dependent pathways, and implicated in various cardiovascular diseases, including atherosclerosis, myocardial infarction, myocardial ischemia-reperfusion injury (IRI), heart failure, diabetic cardiomyopathy, dilated cardiomyopathy, hypertrophic cardiomyopathy, chemotherapy drug-induced cardiomyopathy, and abdominal aortic aneurysm (AAA). To further investigate potential therapeutic targets for cardiovascular diseases, we also analyzed the main molecules and their inhibitors involved in necroptosis in an effort to uncover insights for treatment.

Ischemic heart disease (IHD) is a significant global health concern, resulting in high rates of mortality and disability among patients. Although coronary blood flow reperfusion is a key treatment for IHD, it often leads to acute myocardial ischemia-reperfusion injury (IRI). Current intervention strategies have limitations in providing adequate protection for the ischemic myocardium. DJ-1, originally known as a Parkinson's disease related protein, is a highly conserved cytoprotective protein. It is involved in enhancing mitochondrial function, scavenging reactive oxygen species (ROS), regulating autophagy, inhibiting apoptosis, modulating anaerobic metabolism, and exerting anti-inflammatory effects. DJ-1 is also required for protective strategies, such as ischemic preconditioning, ischemic postconditioning, remote ischemic preconditioning and pharmacological conditioning. Therefore, DJ-1 emerges as a potential target for the treatment of myocardial IRI. Our comprehensive review delves into its protective mechanisms in myocardial IRI and the structural foundations underlying its functions.

AIMS:To investigate the role of FOXO1 in STAT3 activation and mitochondrial quality control in the diabetic heart. METHODS:Type 1 diabetes mellitus (T1DM) was induced in rats by a single intraperitoneal injection of 60 mg · kg-1 streptozotocin (STZ), while type 2 diabetes mellitus (T2DM) was induced in rats with a high-fat diet through intraperitoneal injection of 35 mg · kg-1 STZ. Primary neonatal mouse cardiomyocytes and H9c2 cells were exposed to low glucose (5.5 mM) or high glucose (HG; 30 mM) with or without treatment with the FOXO1 inhibitor AS1842856 (1 μM) for 24 hours. In addition, the diabetic db/db mice (aged 8 weeks) and sex- and age-matched non-diabetic db/+ mice were treated with vehicle or AS1842856 by oral gavage for 15 days at a dose of 5 mg · kg-1  · d-1 . RESULTS:Rats with T1DM or T2DM had excessive cardiac FOXO1 activation, accompanied by decreased STAT3 activation. Immunofluorescence and immunoprecipitation analysis showed colocalization and association of FOXO1 and STAT3 under basal conditions in isolated cardiomyocytes. Selective inhibition of FOXO1 activation by AS1842856 or FOXO1 siRNA transfection improved STAT3 activation, mitophagy and mitochondrial fusion, and decreased mitochondrial fission in isolated cardiomyocytes exposed to HG. Transfection with STAT3 siRNA further reduced mitophagy, mitochondrial fusion and increased mitochondrial fission in HG-treated cardiomyocytes. AS1842856 alleviated cardiac dysfunction, pathological damage and improved STAT3 activation, mitophagy and mitochondrial dynamics in diabetic db/db mice. Additionally, AS1842856 improved mitochondrial function indicated by increased mitochondrial membrane potential and adenosine triphosphate production and decreased mitochondrial reactive oxygen species production in isolated cardiomyocytes exposed to HG. CONCLUSIONS:Excessive FOXO1 activation during diabetes reduces STAT3 activation, with subsequent impairment of mitochondrial quality, ultimately promoting the development of diabetic cardiomyopathy.

Diabetes mellitus is a metabolic disease with a high prevalence worldwide, and cardiovascular complications are the leading cause of mortality in patients with diabetes. Diabetic cardiomyopathy (DCM), which is prone to heart failure with preserved ejection fraction, is defined as a cardiac dysfunction without conventional cardiac risk factors such as coronary heart disease and hypertension. Mitochondria are the centers of energy metabolism that are very important for maintaining the function of the heart. They are highly dynamic in response to environmental changes through mitochondrial dynamics. The disruption of mitochondrial dynamics is closely related to the occurrence and development of DCM. Mitochondrial dynamics are controlled by circadian clock and show oscillation rhythm. This rhythm enables mitochondria to respond to changing energy demands in different environments, but it is disordered in diabetes. In this review, we summarize the significant role of circadian clock-controlled mitochondrial dynamics in the etiology of DCM and hope to play a certain enlightening role in the treatment of DCM.

Objective:To evaluate the role of caveolin 3 (Cav-3) in diabetic cardiomyopathy and the relationship with endoplasmic reticulum stress in mice.Methods:This experiment was performed in two parts. Part Ⅰ in vivo experiment Sixteen clean-grade healthy adult male wild type mice weighing 18-20 g, were divided into 2 groups ( n=8 each) using a random number table method: control group(Control group) and diabetic cardiomyopathy group (DCM group). Another 8 Cav-3 KO mice were selected and served as Cav-3 KO + diabetic cardiomyopathy group (Cav-3 KO+ DCM group). Type 2 diabetic models were developed by high fat diet combined with intraperitoneal injection of streptozotocin (100 mg/kg). The left ventricular ejection fraction (EF), left ventricular short axis shortening rate (FS), left ventricular end-systolic diameter (LVESD) and left ventricular end-diastolic diameter (LVEDD) were measured by B ultrasound at 8 weeks. Then the mice were sacrificed, and the myocardial histomorphology was observed using HE staining. Part Ⅱ in vitro experiment HL-1 cardiomyocytes were divided into 3 groups ( n=6 each)using a random number table method: normal glucose group (NG group), high glucose group (HG group) and high glucose+ methyl-β-cyclodextrin group (HG+ β-CD group). The high glucose model was prepared by adding 50% glucose to a specialized culture medium until the final concentration reached 30 mmol/L, and HL-1 cardiomyocytes were continuously cultivated for 36 h. The cellular injury was assessed using LDH and CCK8 kits. The expression of endoplasmic reticulum stress-related proteins binding immunoglobulin protein (BiP), C/EBP-homologous protein (CHOP) and X-box binding protein 1 (XBP1-s) in myocardial tissues and HL-1 cells was detected by Western blot. Results:In vivo experiment Compared with Control group, the food intake, water intake, and heart mass/body mass were significantly increased, EF and FS were decreased, LVESD and LVEDD were increased, the expression of BiP, CHOP and XBP1-s was up-regulated, the expression of Cav-3 was down-regulated ( P<0.05), and the pathological damage was aggravated in DCM group and Cav-3 KO+ DCM group. Compared with DCM group, EF and FS were significantly decreased, LVESD and LVEDD were increased, the expression of BiP, CHOP and XBP1-s was up-regulated, the expression of Cav-3 was down-regulated ( P<0.05), and the pathological damage was aggravated in Cav-3 KO+ DCM group. In vitro experiment Compared with NG group, the cell viability was significantly decreased, LDH activity was increased, the expression of BiP, CHOP and XBP1-s was up-regulated, and the expression of Cav-3 was down-regulated in HG group and HG+ β-CD group ( P<0.05). Compared with HG group, the cell viability was significantly decreased, LDH was increased, the expression of BiP, CHOP and XBP1-s was up-regulated, and the expression of Cav-3 was down-regulated in HG+ β-CD group ( P<0.05). Conclusions:Down-regulation of Cav-3 expression aggravates myocardial injury in diabetes mellitus, and the mechanism is related to excessive activation of endoplasmic reticulum stress in mice.

Background: As an independent risk factor, diabetes can cause irreversible damage to the myocardium (i.e., diabetic cardiomyopathy), which seriously affecting the mortality of patients with diabetes. Diabetic cardiomyopathy has received sustained attention over the past decade, but its pathogenesis and effective treatments are still lacking. Endoplasmic reticulum (ER) stress plays a full role in maintaining cellular redox balance, cell structure and function, etc., thus laying a foundation for its important role in diabetic cardiomyopathy. In order to fully clarify the basis, research status and hot frontier directions of ER stress in diabetic cardiomyopathy, we used bibliometric to construct this visual analysis.Method: Publications related to the application of ER stress in diabetic cardiomyopathy as of December 31, 2022 were searched in the web of science core collection (WoSCC) database. VOSviewers, CiteSpace and R package “bibliometrix” were used to conduct this bibliometric analysis.Results: 223 articles from 355 institutions in 41 countries were included in this study, including 145 articles and 78 reviews. Overall, the volume of postings is increasing year by year. 《Diabetes》, 《Cardiovascular Research》 and《Journal of Cellular and Molecular Medicine》are the most popular journals in the field of studying the role of ER stress in diabetic cardiomyopathy, The journal with the most publications is Nutrients which is the most co-cited journal meanwhile. A total of 1,252 authors participated in this study. Professor Cai Lu, Professor Ren Jun and Professor Tan Yi are the authors with the most publications, while Boudina S is the author with the most citations. Exploring the occurrence and development of diabetic cardiomyopathy based on various cell death methods mediated by ER stress is still a hot topic in this field. It is evidenced by the high frequency keywords "Apoptosis", "Oxidative stress", "Autophagy", and the burst keyword of "cell death”. Conclusion: This is the first bibliometric study to comprehensively summarize research trends and advances in the role of ER stress in diabetic cardiomyopathy. This article describes the research background and progress in this field, and further points out the recent research frontiers and hot spots, allowing researchers to fully explore ER stress and the various cell death methods it induces. It is hoped that this series of work will provide new insights and help for the clinical treatment of diabetic cardiomyopathy.

缺血性心脏病是糖尿病患者死亡的重要原因,恢复缺血心肌组织灌注是其根本治疗措施,但可导致心肌缺血再灌注损伤.线粒体稳态对高能量需求的心肌细胞的正常生理活动有重要意义.线粒体稳态的维持依赖于线粒体融合和分裂即线粒体动力学.糖尿病时,糖脂代谢紊乱可导致线粒体动力学相关蛋白的变化,引起线粒体动力学失衡,从而导致糖尿病心肌细胞线粒体功能障碍,促进糖尿病缺血性心脏病的发生、发展,其机制可能与活性氧爆发、钙超载、线粒体通透性转换孔开放、自噬紊乱、内质网应激、细胞凋亡及焦亡等有关.本文就线粒体动力学在糖尿病心肌缺血再灌注损伤中作用的研究进展作一综述.

Objective:To investigate the effects of protein kinase Cβ2 (PKCβ2) in the pyroptosis of cardiac myocytes induced by hypoxia/reoxygenation (HR).Methods:H9c2 myocardial cells were cultured and divided into the five groups according to the random number table method ( n=6): a low-glucose (LG) group, a low-glucose and hypoxia reoxygenation (LG+HR) group, a high-glucose (HG) group, a high-glucose and hypoxia reoxygenation (HG+HR) group and a hyperglycemic reoxygenation and PKCβ2 inhibitor CGP53353 (1 μmol/L) (HG+HR+CGP) group. A cell model of HR was established through hypoxia in a three-gas incubator (5%CO 2, 94%N 2, and 1%O 2) for 4 h followed by reoxygenation at a normal oxygen concentration for 2 h. The cell viability was evaluated by cell counting kit 8 (CCK8) and the level of lactate dehydrogenase (LDH) was determined by enzyme-linked immunosorbent assay (ELISA). The levels of PKCβ2, Nod-like receptor pyrin domain3 (NLRP3), interleukin-1β (IL-1β) and caspase-1 were detected by Western blot, while the mitochondrial membrane potential of H9c2 cells was evaluated by JC-1 staining. Results:Compared with the LG group, the HG group, the LG+HR group and the HG+HR group showed significantly decreased cell survival rates but increased LDH release ( P<0.05), as well as up-regulation in phosphorylated PKCβ2 and the expression of NLRP3, IL-1β and caspase-1 ( P<0.05). Compared with the HG group, the HG+HR group showed increased LDH release and a decreased cell survival rate ( P<0.05), as well as up-regulation in JC-1 cell percentage and the expression of phosphorylated PKCβ2 [phospho-PKCβ2(Ser660), P-PKCβ2]protein, NLRP3, IL-1β, and caspase-1 ( P<0.05). Compared with the LG+ HR group, the HG+HR group showed increased LDH release and a decreased cell survival rate ( P<0.05), as well as significantly increased expression of P-PKCβ2 and up-regulated expression of NLRP3, IL-1β and caspase-1 ( P<0.05). Compared with the HG+HR group, the HG+HR+CGP group presented a significantly increased survival rate and decreased LDH release, as well as down-regulation in JC-1 cell percentage and the expression of P-PKCβ2, NLRP3, IL-1β and caspase-1 ( P<0.05). Conclusions:Selective inhibition of PKCβ2 overactivation can relieve hyperglycemic HR injury in cardiomyocytes, which may be related to relieving pyroptosis and inhibiting mitochondrial damage.

Lipopolysaccharide (LPS)-induced autophagy is involved in sepsis-associated myocardial injury with increased PKCβ2 activation. We previously found hyperglycemia-induced PKCβ2 activation impaired the expression of caveolin-3 (Cav-3), the dominant isoform to form cardiomyocytes caveolae which modulate eNOS signaling to confer cardioprotection in diabetes. However, little is known about the roles of PKCβ2 in autophagy and Cav-3/eNOS signaling in cardiomyocytes during LPS exposure. We hypothesize LPS-induced PKCβ2 activation promotes autophagy and impairs Cav-3/eNOS signaling in LPS-treated cardiomyocytes. H9C2 cardiomyocytes were treated with LPS (10 µg/mL) in the presence or absence of PKCβ2 inhibitor CGP53353 (CGP, 1 µM) or autophagy inhibitor 3-methyladenine (3-MA, 10 µM). LPS stimulation induced cytotoxicity overtime in H9C2 cardiomyocytes, accompanied with excessive PKCβ2 activation. Selective inhibition of PKCβ2 with CGP significantly reduced LPS-induced cytotoxicity and autophagy (measured by LC-3II, Beclin-1, p62 and autophagic flux). In addition, CGP significantly attenuated LPS-induced oxidative injury, and improved Cav-3 expression and eNOS activation, similar effects were shown by the treatment of autophagy inhibitor 3-MA. LPS-induced myocardial injury is associated with excessive PKCβ2 activation, which contributes to elevated autophagy and impaired Cav-3/eNOS signaling. Selective inhibition of PKCβ2 improves Cav-3/eNOS signaling and attenuates LPS-induced injury through inhibiting autophagy in H9C2 cardiomyocytes.

BACKGROUND:The outbreak of 2019 novel coronavirus disease (COVID-19) in Wuhan, China, has spread rapidly worldwide. In the early stage, we encountered a small but meaningful number of patients who were unintentionally scheduled for elective surgeries during the incubation period of COVID-19. We intended to describe their clinical characteristics and outcomes.METHODS:We retrospectively analyzed the clinical data of 34 patients underwent elective surgeries during the incubation period of COVID-19 at Renmin Hospital, Zhongnan Hospital, Tongji Hospital and Central Hospital in Wuhan, from January 1 to February 5, 2020.FINDINGS:Of the 34 operative patients, the median age was 55 years (IQR, 43-63), and 20 (58·8%) patients were women. All patients developed COVID-19 pneumonia shortly after surgery with abnormal findings on chest computed tomographic scans. Common symptoms included fever (31 [91·2%]), fatigue (25 [73·5%]) and dry cough (18 [52·9%]). 15 (44·1%) patients required admission to intensive care unit (ICU) during disease progression, and 7 patients (20·5%) died after admission to ICU. Compared with non-ICU patients, ICU patients were older, were more likely to have underlying comorbidities, underwent more difficult surgeries, as well as more severe laboratory abnormalities (eg, hyperleukocytemia, lymphopenia). The most common complications in non-survivors included ARDS, shock, arrhythmia and acute cardiac injury.INTERPRETATION:In this retrospective cohort study of 34 operative patients with confirmed COVID-19, 15 (44·1%) patients needed ICU care, and the mortality rate was 20·5%.FUNDING:National Natural Science Foundation of China.

目的 探讨抗氧化剂N-乙酰半胱氨酸(N-acetylcysteine,NAC)对糖尿病大鼠心肌缺血再灌注(ischemia reperfusion,IR)损伤后肝、肾功能的影响.方法 36只雄性SD大鼠随机分为对照假手术组、对照IR组、糖尿病假手术组、糖尿病IR组、糖尿病NAC治疗后假手术组和糖尿病NAC治疗后IR组,每组各6只.糖尿病假手术组、糖尿病IR组、糖尿病NAC治疗后假手术组和糖尿病NAC治疗后IR组大鼠经腹腔注射链脲佐菌素60 mg/kg制备1型糖尿病模型.糖尿病模型制备成功1周后,糖尿病NAC治疗后假手术组和糖尿病NAC治疗后IR组大鼠灌胃给予NAC1.5 g/(kg·d),其余各组大鼠给予等体积生理盐水,持续4周,对照IR组、糖尿病IR组和糖尿病NAC治疗后IR组通过结扎左冠状动脉前降支30 min,再灌注120min制备IR模型.采用生物化学法检测大鼠血清谷丙转氨酶(glutamate pyruvic transaminase,GPT)、谷草转氨酶(glutamic oxaloacetic transaminase,GOT)、乳酸脱氢酶(lactate dehydrogenase,LDH)、肌酸激酶(creatine kinase,CK)、肌酐(serum creatinine,SCr)水平,采用WST-1法检测大鼠血清超氧化物歧化酶(superoxide dismutase,SOD)活性,采用TBA法检测大鼠血清过氧化物丙二醛(peroxide malondialdehyde,MDA)水平.结果 糖尿病4组大鼠血清GPT、GOT、LDH、SCr及MDA水平均高于对照IR组和对照假手术组(P＜0.05),血清SOD活性低于对照假手术组(P＜0.05).糖尿病NAC治疗后IR组大鼠血清GPT、GOT、LDH、SCr水平低于糖尿病IR组(P＜0.05),血清MDA水平[(19.38±0.56)μmol/L]低于糖尿病IR组[(27.75±1.30)μmol/L](P＜0.05),SOD活性[(128.85士7.28)u/mL]高于糖尿病IR组[(105.72±10.13)u/mL](P＜0.05).糖尿病NAC治疗后假手术组大鼠血清GPT、GOT、LDH、SCr水平低于糖尿病假手术组(P＜0.05),血清MDA水平[(13.38±0.62)μmol/L]低于糖尿病假手术组[(19.90±1.30) μ上mol/L](P＜ 0.05),SOD活性[(177.33±6.20) u/mL]高于糖尿病假手术组[(153.24±8.89) u/mL] (P＜0.05).糖尿病NAC治疗后IR组大鼠血清GPT、GOT、LDH、SCr和MDA水平高于糖尿病NAC治疗后假手术组(P＜0.05),SOD活性低于糖尿病NAC治疗后假手术组(P＜0.05).糖尿病IR组大鼠血清GPT、GOT、LDH、SCr和MDA水平高于糖尿病假手术组(P＜0.05),SOD活性低于糖尿病假手术组(P＜0.05).结论 NAC可减轻糖尿病大鼠合并IR损伤模型的氧化应激反应,从而降低对肝、肾功能的损伤.

Objective: To analyze the infectivity of latent coronavirus disease 2019 (COVID-19) in the operating room, and describe their postoperative outcomes Methods: Fourteen surgical patients with latent SAR-CoV-2 infection in January 2020, in Renmin Hospital of Wuhan University were selected as the research objects We investigated the contact infection between medical staff and patients The general information, clinical symptoms and signs, and postoperative outcome of the patients were also analyzed Results: In the operating room, 42 healthcare workers (47 person-times in total) were isolated under medical observation after contacting with the patients At last, 3 healthcare workers were diagnosed as COVID-19 All these 14 patients were laboratory-confirmed SARS-CoV-2 infection in 3-7 days after surgery In terms of signs and symptoms, 12 patients had fever, 10 patients felt fatigue, and 9 patients had dry cough In terms of postoperative outcome, 1 patient died, 13 patients (including 1 mild, 7 general, and 5 severe cases) were transferred to the designated hospitals according to the local health committee Conclusion: Patients with SARS-CoV-2 infection are highly infectious even in the operating room environment The stress of anesthesia and operation may exacerbate the progression of COVID-19, and worsen the outcome of patients © 2020, Editorial Board of Medical Journal of Wuhan University All right reserved

The coronavirus disease 2019 (COVID-19) became a global pandemic. Males, compared to females, seem to be more susceptible to COVID-19, but related evidence is scarce, especially in severe patients. We explored sex differences in clinical characteristics and potential risk factors for mortality in severe COVID-19 patients. In this retrospective cohort study, we included all severe COVID-19 patients admitted to Eastern Renmin Hospital of Wuhan University, Wuhan, China, with a definitive clinical outcome as of Apr 10, 2020. Of the included 651 patients, 332 were male, and 319 were female. Males and females did not differ in age and underlying comorbidities. Males were more likely than females to report fever and develop serious complications, including acute respiratory distress syndrome, secondary infection, acute cardiac injury, coagulopathy, acute kidney injury and arrhythmia. Further, males had much higher mortality relative to females. Multivariable regression showed neutrophilia (odds ratio 6.845, 95% CI 1.227-38.192, p=0.028), thrombocytopenia (19.488, 3.030-25.335, p=0.002), hypersensitive troponin I greater than 0.04 pg/mL (6.058, 1.545-23.755, p=0.010), and procalcitonin greater than 0.1 ng/mL (6.350, 1.396-28.882, p=0.017) on admission were associated with in-hospital death. With either of these risk factors, the cumulative survival rate was relatively lower in males than in females. In conclusion, males are more likely than females to develop serious complications and progress to death. The potential risk factors of neutrophilia, thrombocytopenia, hypersensitive troponin I greater than 0.04 pg/mL and procalcitonin more than 0.1 ng/mL may help clinicians to identify patients with poor outcomes at an early stage, especially in males.

Objective:To explore the effects of glycine on myocardial caveolin-3/endothelial nitric oxide synthase (eNOS) signal and oxidative stress in diabetic myocardium of rats.Methods:According to random number table method, 30 adult male SD rats at 8 weeks of age were randomly divided into 3 groups (10 in each group): the control group (C), diabetes mellitus group (D, diabetes model induced by single intraperitoneal streptozotocin injection), diabetes+glycine treatment group (D+Gly, after the success of the diabetes model, treated by 1% glycine aqueous solution instead of drinking water treatment for 8 weeks). The H9C2 cells were exposed to 30 mmol/L glucose and 140 μmol/L glycine context and cultured for 48 hours. The contents of super oxide dismutase (SOD), malondialdehyde (MDA), lactate dehydrogenase (LDH) and total protein and CCK-8 test were detected using commercial assay kits. HE staining was used to detect the pathological changes of diabetic myocardium, and the expression of caveolin-3 and p-eNOS were detected by Western blot. One-way analysis of variance was used for comparison between groups, and Tukey test was used for pairwise comparison.Results:(1) The MDA content of myocardial tissue were significantly higher in rats of diabetes group than that in control group ( q=6.57, P<0.05). The SOD content of myocardial tissue and the expression levels of caveolin-3 and p-eNOS were significantly lower in rats of diabetes group than that in control group ( q=15.72, 11.84, 15.18, all P<0.05). (2) The MDA content of myocardial tissue were significantly lower in diabetic rats treated with glycine than that in untreated diabetic rats [(4.81±0.94) vs (6.06±0.85) nmol/mg prot, q=4.51, P<0.05]. The SOD content of myocardial tissue and the expression of caveolin-3 and p-eNOS were significantly higher in diabetic rats treated with glycine than that in untreated diabetic rats [(73.17±11.83) vs (42.01±10.35) U/mg prot, 0.78±0.08 vs 0.55±0.14, 0.83±0.13 vs 0.50±0.12, q=9.17, 6.05, 10.02, all P<0.05]. (3) The SOD content, caveolin-3 and p-eNOS expression were significantly decrease in H9C2 cardiomyocytes in high glucose group than that in low glucose group ( q=10.04, 10.20, 18.25, all P<0.05), while the MDA content was significantly higher than low glucose group ( q=18.98, P<0.05). (4) The SOD content, caveolin-3, p-eNOS protein expression were significantly higher in high glucose-exposed H9C2 cardiomyocytes with versus without glycine treatment [(11.35±1.64) vs (7.61±1.02) U/mg prot, 0.91±0.06 vs 0.77±0.05, 0.74±0.04 vs 0.62±0.06, q=4.21, 6.21, 5.77, all P<0.05], while MDA content was significantly lower than untreated group [(1.42±0.08) vs (2.07±0.15) nmol/mg prot, q=10.82, P<0.05]. Conclusion:Glycine exerted diabetic myocardial protection may through regulating caveolin-3/eNOS signal and alleviating oxidative stress injury.

Diabetic hearts are more susceptible to myocardial ischemia/reperfusion (I/R) injury and less sensitive to ischemic postconditioning (IPostC), but the underlying mechanisms remain unclear. PKCβ2 is preferentially overactivated in diabetic myocardium, in which autophagy status is abnormal. This study determined whether hyperglycemia-induced PKCβ2 activation resulted in autophagy abnormality and compromised IPostC cardioprotection in diabetes. We found that diabetic rats showed higher cardiac PKCβ2 activation and lower autophagy than control at baseline. However, myocardial I/R further increased PKCβ2 activation and promoted autophagy status in diabetic rats. IPostC significantly attenuated postischemic infarct size and CK-MB, accompanied with decreased PKCβ2 activation and autophagy in control but not in diabetic rats. Pretreatment with CGP53353, a selective inhibitor of PKCβ2, attenuated myocardial I/R-induced infarction and autophagy and restored IPostC-mediated cardioprotection in diabetes. Similarly, CGP53353 could restore hypoxic postconditioning (HPostC) protection against hypoxia reoxygenation- (HR-) induced injury evidenced by decreased LDH release and JC-1 monomeric cells and increased cell viability. These beneficial effects of CGP53353 were reversed by autophagy inducer rapamycin, but could be mimicked by autophagy inhibitor 3-MA. It is concluded that selective inhibition of PKCβ2 could attenuate myocardial I/R injury and restore IPostC-mediated cardioprotection possibly through modulating autophagy in diabetes.

Diabetic hearts are more vulnerable to ischemia/reperfusion (I/R) injury and less responsive to remifentanil preconditioning (RPC), but the underlying mechanisms are incompletely understood. Caveolin-3 (Cav-3), the dominant isoform of cardiomyocyte caveolae, is reduced in diabetic hearts in which oxidative stress is increased. This study determined whether the compromised RPC in diabetes was an independent manifestation of hyperglycemia-induced oxidative stress or linked to impaired Cav-3 expression with associated signaling abnormality. RPC significantly attenuated postischemic infarction, cardiac dysfunction, myocardial apoptosis, and 15-F2t-isoprostane production (a specific marker of oxidative stress), accompanied with increased Cav-3 expression and enhanced Akt and STAT3 activation in control but not in diabetic rats. Pretreatment with the antioxidant N-acetylcysteine (NAC) attenuated hyperglycemia-induced reduction of Cav-3 expression and Akt and STAT3 activation and restored RPC-mediated cardioprotection in diabetes, which was abolished by cardiac-specific knockdown of Cav-3 by AAV9-shRNA-Cav-3, PI3K/Akt inhibitor wortmannin, or JAK2/STAT3 inhibitor AG490, respectively. Similarly, NAC could restore RPC protection from high glucose and hypoxia/reoxygenation-induced injury evidenced by decreased levels of LDH release, 15-F2t-isoprostane, O2-, and JC-1 monomeric cells, which were reversed by caveolae disrupter methyl-β-cyclodextrin, wortmannin, or AG490 in isolated primary cardiomyocytes or siRNAs of Cav-3, Akt, or STAT3 in H9C2 cells. Either methyl-β-cyclodextrin or Cav-3 knockdown reduced Akt and STAT3 activation. Further, the inhibition of Akt activation by a selective inhibitor or siRNA reduced STAT3 activation and vice versa, but they had no effects on Cav-3 expression. Thus, hyperglycemia-induced oxidative stress abrogates RPC cardioprotection by impairing Cav-3-modulated PI3K/Akt and JAK2/STAT3 signaling. Antioxidant treatment with NAC could restore RPC-induced cardioprotection in diabetes by improving Cav-3-dependent Akt and STAT3 activation and by facilitating the cross talk between PI3K/Akt and JAK2/STAT3 signaling pathways.

目的:用甲基乙二醛培养的H9C2心肌细胞进行利多卡因预处理后进行缺氧/复氧(H/R)处理,探究利多卡因预处理是否通过影响时钟基因BMAL1改善甲基乙二醛培养的H9C2心肌细胞缺氧/复氧损伤.方法:将H9C2细胞培养分为4组:即正常对照(N)组、甲基乙二醛(MGO)组、MGO+H/R组、MGO+H/R+LP组(缺氧/复氧前培养液中加入利多卡因20 μmol/L).收集各组细胞,用CCK-8法测定细胞活力;收集细胞培养上清液测定乳酸脱氢酶(LDH)漏出量;超声破碎收集细胞匀浆测定细胞超氧化物歧化酶(SOD)活性;流式细胞术测定细胞凋亡率;Western Blot测定BMAL1表达.结果:与N组相比,其余各组CCK-8检测细胞活性降低,LDH检测乳酸脱氢酶漏出量增多,SOD活性降低(P＜0.01),凋亡率增高(P＜0.01),BMAL1表达降低,与MGO组比较,MGO+H/R组CCK-8检测细胞活性降低,LDH漏出量增多,SOD活性降低(P＜0.01),凋亡率增高(P＜0.01),BMAL1表达降低(P＜0.01),MGO+H/R+LP组以上指标降低不明显.结论:利多卡因预处理可能通过上调时钟基因BMAL1蛋白表达,以改善甲基乙二醛培养的H9C2心肌细胞缺氧/复氧后的细胞损伤.

叉头转录因子O亚型1( FoxO1)是人体内重要的转录因子之一,参与调节机体葡萄糖代谢、脂质代谢、氧化应激、凋亡、自噬和内质网应激等基因的表达,调控胰岛素信号通路等而发挥生物学功能.心肌缺血再灌注损伤( IRI)是临床上糖尿病患者常见的一种机体损伤,并可带来心肌顿抑等不良后果.近年来,越来越多的实验证明FoxO1参与糖尿病心肌IRI的过程,FoxO1 通过磷酸化等途径活化,同时发现FoxO1 过度活化会加剧心肌IRI.研究FoxO1在糖尿病心肌IRI中的具体作用机制,有助于为临床糖尿病心肌IRI保护治疗提供新的靶点与思路.