基于PI3K/AKT信号通路的谷红注射液抗H9c2心肌细胞缺氧/复氧损伤的机制研究

目的基于PI3K/AKT信号通路,探讨谷红注射液(guhong injection,GHI)对H9c2心肌细胞缺氧/复氧(H/R)损伤的保护作用。方法培养H9c2心肌细胞,CCK-8比色法筛选GHI实验剂量。将细胞随机分为8组:正常组、模型组、GHI低、中、高剂量组(30、60和90μL·mL^-1)、阳性药组(维拉帕米注射液7.5μL·mL^-1)、GHI+LY294002(PI3K抑制剂)组和LY294002组。除正常组外,其他组均建立缺氧4 h复氧16 h的H/R损伤模型。ELISA检测各组细胞内肌酸激酶同工酶(CKMB)、乳酸脱氢酶(LDH)、超氧化物歧化酶(SOD)活性及丙二醛(MDA)含量,Western blot法检测各组细胞内p-PI3K、PI3K、p-AKT、AKT及GSK-3β蛋白表达水平。结果与模型组相比,各给药组LDH、CK-MB均降低(P<0.05),MDA降低(P<0.01)、SOD升高(P<0.01)。p-PI3K/PI3K、p-AKT/AKT及GSK-3β蛋白表达水平均升高(P<0.01)。给予LY294002后,与模型组相比,LDH、CK-MB、MDA及SOD无显著性差异,p-PI3K/PI3K、p-AKT/AKT及GSK-3β蛋白表达水平均降低(P<0.01)。结论GHI可以明显减轻H/R对H9c2心肌细胞造成的损伤,表现出抗氧化应激与抗凋亡的作用,其作用机制可能与PI3K/AKT信号通路有关。     

恩格列净及达格列净对棕榈酸诱导的心肌细胞损伤的保护作用及其机制

目的 探讨钠-葡萄糖共转运蛋白-2抑制剂恩格列净（empagliflozin,EMPA）及达格列净（dapagliflozin,DAPA）对棕榈酸（palmitic acid,PA）诱导H9c2心肌细胞损伤的保护作用及其可能机制。方法 采用PA诱导H9c2心肌细胞损伤,CCK-8法筛选PA、EMPA及DAPA的最佳给药浓度;Western blotting检测TLR4、p-AKT、p-mTOR、Nrf2和HO-1的蛋白表达水平;ELISA法检测IL-1β、IL-6和TNF-α的含量;荧光显微镜和流式细胞术检测PA诱导H9c2心肌细胞中ROS水平。结果 PA 100 μmol·L^–1刺激24 h可诱导H9c2心肌细胞存活率明显下降（P<0.01）,IL-1β、IL-6、TNF-α、TLR4蛋白表达、p-mTOR蛋白表达及ROS水平明显增加（P<0.01）,p-AKT、Nrf2和HO-1蛋白表达显著降低（P<0.01）;与模型组比较,经EMPA及DAPA处理后,细胞存活率明显增加（P<0.01）,IL-1β、IL-6、TNF-α、TLR4蛋白表达、p-mTOR蛋白表达及ROS水平明显降低（P<0.05或P<0.01）,p-AKT、Nrf2和HO-1蛋白表达显著上调（P<0.05或P<0.01）。结论 EMPA及DAPA对PA诱导的心肌细胞损伤均具有保护作用,其机制可能与下调TLR4、p-mTOR蛋白表达,增强AKT蛋白磷酸化,激活Nrf2/HO-1通路,抑制ROS的生成有关。     

miR-195缓解脂多糖诱导的H9c2心肌细胞凋亡、氧化应激及炎症反应

目的探讨miR-195对脂多糖(LPS)诱导的H9C2心肌细胞凋亡、氧化应激、炎症反应的影响。方法将H9C2心肌细胞随机分成空白对照组、脂多糖组(LPS)、LPS+miR-NC组、LPS+miR-195组;RT-PCR检测转染后miR-195表达量;ELISA检测心肌损伤标记物水平(CK-MB、Mb、cTnI);流式细胞术检测细胞凋亡率;Hoechst染色观察细胞核形的变化;Western blot检测氧化应激相关蛋白表达(p-Nrf2/Nrf2、PGC-1α);试剂盒检测氧化应激标记物SOD活性;ELISA检测炎症因子水平(IL-6、IL-1β、iNOS)。结果与LPS+miR-NC组相比,LPS+miR-195组miR-195表达量、氧化应激标记物水平(p-Nrf2/Nrf2、PGC-1α)、抗氧化酶SOD活性均显著升高(P<0.05);与LPS+miR-NC组相比,LPS+miR-195组心肌损伤标记物水平(CK-MB、Mb、cTnI)、细胞凋亡率、炎症因子水平(IL-6、IL-1β、iNOS)均显著降低(P<0.05);与LPS+miR-NC组相比,LPS+miR-...     

灵芝多糖肽对培养乳大鼠心肌细胞缺氧复氧损伤的保护作用

目的研究灵芝多糖肽(GLPP)对培养乳大鼠心肌细胞缺氧/复氧(H/R)损伤的保护作用。方法用出生1~3 d的SD乳大鼠进行心肌细胞原代培养,取培养3~4 d的心肌细胞分为正常对照组、H/R组和GLPP给药组(12.5,25,50和100 mg·L-1)。MTT法检测细胞存活率;电镜检测细胞形态改变和线粒体损伤;用AnnexinⅤ-FITC/PI双标记细胞,流式细胞仪检测细胞凋亡百分率;以Fluo-3/AM荧光指示剂负载,用激光扫描共聚焦显微镜观察心肌细胞内钙离子荧光强度变化;以活性氧(ROS)敏感的荧光探针2,7-二氢二氯荧光素(DCFH-DA)标记细胞,激光共聚焦显微镜下观察ROS含量变化。结果与正常对照组比较,H/R组细胞存活率降低(P<0.05);GLPP 12.5,25,50和100 mg·L-1组细胞存活率与H/R组比较明显增加(P<0.01)。与正常对照组比较,H/R组可见线粒体损伤,GLPP给药组可以减轻线粒体损伤。流式细胞仪检测结果表明,与正常对照组比较,H/R组细胞凋亡率增加(P<0.01);GLPP组与H/R组比较细胞凋亡率明显减小(P<0.01)。与正常对照组比较,H/R组[Ca2+]i增加,细胞内ROS含量增高(P<0.01);与H/R组比较,GLPP给药组细胞[Ca2+]i减少,细胞内ROS含量降低(P<0.01)。结论GLPP对H/R损伤的乳大鼠心肌细胞具有保护作用,其作用机制可能与减少细胞内自由基含量和减轻细胞内钙超负荷有关。     

Increased expression of 78 kD glucose-regulated protein promotes cardiomyocyte apoptosis in a rat model of liver cirrhosis

Aims: This study was to investigate the role and underlying mechanism of 78 kD glucose-regulated protein (GRP78) in cardiomyocyte apoptosis in a rat model of liver cirrhosis. Methods: A rat model of liver cirrhosis was established with multiple pathogenic factors. A total of 42 male SD rats were randomly divided into the liver cirrhosis group and control group. Cardiac structure analysis was performed to assess alterations in cardiac structure. Cardiomyocytes apoptosis was detected by TdT-mediated dUTP nick end labeling method. Expression of GRP78, CCAAT/enhancer-binding protein homologous protein (CHOP), caspase-12, nuclear factor kappa-light-chain-enhancer of activated B cells p65 subunit (NF-κB p65) and B cell lymphoma-2 (Bcl-2) was detected by immunohistochemical staining. Results: The ratios of left ventricular wall thickness to heart weight and heart weight to body weight were significantly increased with the progression of liver cirrhosis (P < 0.05). Apoptosis index of cardiomyocytes was significantly increased with the progression of liver cirrhosis (P < 0.05). The expression levels of GRP78, CHOP and caspase-12 were significantly increased in the progression of liver cirrhosis (P < 0.05). The expression levels of NF-κB p65 and Bcl-2 were highest in the 4-wk liver cirrhosis, and they were decreased in the 6-wk and 8-wk in the progression of liver cirrhosis. GRP78 expression levels were positively correlated with apoptosis index, CHOP and caspase-12 expression levels (P < 0.05). CHOP expression levels were negatively correlated with NF-κB p65 and Bcl-2 expression levels (P < 0.05). Conclusion: Increased expression of GRP78 promotes cardiomyocyte apoptosis in rats with cirrhotic cardiomyopathy.     

EGCG Blocked Phenylephrin-Induced Hypertrophy in H9C2 Cardiomyocytes,by Activating AMPK-Dependent Pathway

AMP-activated protein kinase (AMPK) is a key regulator of energy metabolism. Previous studies have shown that activation of AMPK results in suppression of cardiac myocyte hypertrophy via inhibition of the p70S6 kinase (p70S6K) and eukaryotic elongation factor-2 (eEF2) signaling pathways. Epigallocatechin-3-gallate (EGCG), the major polyphenol found in green tea, possesses multiple protective effects on the cardiovascular system including cardiac hypertrophy. However, the molecular mechanisms has not been well investigated. In this study, we found that EGCG could significantly reduce natriuretic peptides type A (Nppa), brain natriuretic polypeptide (BNP) mRNA expression and decrease cell surface area in H9C2 cardiomyocytes stimulated with phenylephrine (PE). Moreover, we showed that AMPK is activated in H9C2 cardiomyocytes by EGCG, and AMPK-dependent pathway participates in the inhibitory effects of EGCG on cardiac hypertrophy. Taken together, our findings provide the first evidence that the effect of EGCG against cardiac hypertrophy may be attributed to its activation on AMPK-dependent signaling pathway, suggesting the therapeutic potential of EGCG on the prevention of cardiac remodeling in patients with pressure overload hypertrophy.     

益心解毒方对Nox2和Nox4亚基过表达的心肌细胞NADPH氧化酶活性的影响

目的通过观察益心解毒方含药血清对Nox2、Nox4亚基过表达的H9c2心肌细胞NADPH氧化酶活性的影响,揭示其作用环节是否与干预相应亚型的NADPH氧化酶调控环节有关。方法采用PCR方法扩增Nox2、Nox4基因全长序列,经双酶切、连接载体和转化后提取重组质粒,经酶切鉴定的阳性质粒进行DNA测序,测序正确后按照lipofectamine 2000试剂的说明书瞬时转染H9c2细胞,转染后的心肌细胞分组给予不同的药物干预,24 h后检测NADPH氧化酶活性。结果 1含有Nox2/Nox4亚基的重组质粒载体通过测序鉴定,结果与Gen Bank报道的完全一致。2通过荧光显微镜下观察转染72 h后的H9c2细胞,可见大量发绿色荧光的细胞,流式细胞术计数结果显示转染率均在60%左右,符合实验要求。3空质粒载体组、模型组、益心解毒方组的NADPH氧化酶活性表达明显高于正常组(P<0.01,P<0.05);模型组和益心解毒方组的NADPH氧化酶活性表达高于空载体组(P<0.01);模型组NADPH氧化酶活性表达均明显高于其他各组,而益心解毒方各组的NADPH氧化酶活性表达均明显低于模型组(P<0.01,P<0.05)。结论成功构建大鼠心肌细胞Nox2、Nox4亚基的重组质粒载体,该重组质粒载体可以在心肌细胞中过表达,益心解毒方可以有效地降低NADPH氧化酶活性的表达。提示此复方治疗心衰的机制可能是抑制了Nox2和Nox4型NADPH氧化酶的表达。     

心型脂肪酸结合蛋白对脂多糖所致心肌细胞损伤的保护作用

目的：探讨心型脂肪酸结合蛋白(heart-fatt y acid binding protein,H-FABP)对脂多糖(lipopolysaccharide,LPS) 所致心肌细胞损伤的保护作用。方法：以原代培养的新生大鼠心肌细胞为模型,通过基因转染方式改变H-FABP表 达水平,采用Western印迹、定量PCR检测原代培养中H-FABP的表达。分别检测心肌细胞培养液中TNF-α,IL-1β,乳 酸脱氢酶(lactate dehydrogenase,LDH)含量以及细胞存活率来反映LPS诱导的心肌细胞损伤与炎症反应。结果：LPS处 理24 h能增加H-FABP表达。SiRNA降低H-FABP后,显著促进LPS引起的心肌细胞存活率下降、LDH释放以及TNF-α和 IL-1β释放。相反,H-FABP过表达能显著抑制LPS引起的心肌细胞损伤与炎症反应。结论：H-FABP对LPS引起的心肌 细胞损伤具有保护作用。     

siRNA靶向干扰IL28RA基因对缺氧复氧心肌细胞损伤的保护作用

目的:探讨小干扰RNA(small interference RNA,siRNA)靶向干扰白细胞介素28受体α(interleukin 28 receptor alpha,IL28RA)基因对心肌细胞缺氧复氧损伤的保护作用?方法:设计合成干扰IL28RA基因表达的3对siRNA(siRNA-6158?siRNA-6160?siRNA-6162),采用脂质体转染原代乳大鼠心肌细胞,分为正常对照组?单纯缺氧复氧组?缺氧复氧+阴性对照转染组?缺氧复氧+siRNA-6158转染组?缺氧复氧+siRNA-6160转染组?缺氧复氧+siRNA-6162转染组,探索siRNA转染心肌细胞的合适浓度,检测心肌细胞存活率?培养液中LDH的水平及心肌细胞IL28RA蛋白表达,观察siRNA干扰IL28RA基因对心肌细胞缺氧复氧过程中的保护作用?结果:采用脂质体转染法,siRNA浓度在80 nmol/L对心肌细胞具有较高的转染效率?与单纯缺氧复氧组和缺氧复氧+阴性对照转染组比较,缺氧复氧+siRNA-6158转染组和缺氧复氧+siRNA-6160转染组的LDH活性明显降低(P < 0.05),心肌细胞存活率明显升高 (P < 0.05),IL28RA蛋白表达明显减少(P < 0.05)?结论:干扰IL28RA基因的表达有望成为保护缺氧复氧心肌损伤的重要手段?