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。     

哌唑嗪对去甲肾上腺素诱导心肌细胞凋亡的影响

目的：研究α受体拮抗剂哌唑嗪对去甲肾上腺素诱导的原代培养心肌细胞凋亡的影响。方法：采用噻唑蓝（MTT）法分析原代培养心肌细胞存活率;乳酸脱氢酶（LDH）外漏实验和吉姆萨染色实验观察原代心肌细胞损伤;JC-1免疫荧光实验检测线粒体膜电位变化;Annexin V-FITC/PI双染,流式细胞仪检测细胞凋亡。结果：NE（100 μmol·L^-1）作用于原代培养心肌细胞48 h,细胞存活率降低;LDH外漏增加;细胞形态改变,细胞数减少、胞体膨大、胞核居中、胞间间隙增大,呈明显病理学特征;线粒体膜电位降低;心肌细胞凋亡率增加。哌唑嗪明显改善去甲肾上腺素诱导的原代培养心肌细胞损伤,增加MTT值、降低LDH外漏量、改善心肌细胞病理形态、增加心肌细胞线粒体膜电位、降低心肌细胞凋亡率（P<0.05或P<0.01）。结论：哌唑嗪能显著抑制去甲肾上腺素诱导的心肌细胞凋亡,本实验为α受体阻断剂改善高交感诱导心肌细胞凋亡提供实验基础与理论指导。     

瓜蒌薤白半夏汤不同提取部位对心肌细胞保护作用比较研究

目的 比较瓜蒌薤白半夏汤（GXB）不同提取部位对缺血缺氧心肌细胞的保护作用,初步探寻该经典方剂干预胸痹、心痛的物质基础。方法 称取瓜蒌240 g、薤白90 g、半夏120 g,50%乙醇回流提取,分别用石油醚、氯仿、醋酸乙酯、水饱和正丁醇、水5种不同极性溶剂萃取,得到相应提取部位,及药渣水煎液部位。培养大鼠原代心肌细胞,制备缺血缺氧模型,给予系列浓度（100、10、1、0.1、0.01 mg/mL）的GXB 6种提取部位及瓜蒌皮注射液（阳性对照,100、50、25、5、1 mg/mL）。MTT法检测细胞存活率,倒置显微镜观察细胞形态变化,生化试剂盒检测培养液中肌酸激酶（CK）、肌酸激酶同工酶（CK-MB）活性。结果 与对照组比较,模型组细胞凋亡、坏死明显,细胞存活率显著降低,细胞培养液中CK、CK-MB的活性显著升高（P < 0.05）;质量浓度均为0.1 mg/mL的GXB水饱和正丁醇部位、水溶性部位及药渣水煎部位可以显著逆转缺血缺氧心肌细胞的生长状态、存活率以及培养液中CK、CK-MB活性（P < 0.05）;石油醚、氯仿及醋酸乙酯部位处理的细胞,与模型组无明显差异。结论 GXB的水饱和正丁醇、水溶性及药渣水煎部位对缺血缺氧损伤的心肌细胞具有显著的保护作用。     

心肌细胞损伤模型构建及应用的研究进展

心肌细胞损伤模型目前被广泛应用于心血管疾病的分子机制及药物作用的研究,因各种模型的形成机制不 同,选择合适的模型非常重要。临床心血管疾病的病理变化相对复杂,根据其特点采用的心肌细胞损伤模型主要有过 氧化氢心肌细胞损伤模型、缺氧/复氧心肌细胞损伤模型、阿霉素心肌细胞损伤模型、高糖/高脂心肌细胞损伤模型、异 丙肾上腺素心肌细胞损伤模型等。几种模型均有优缺点,需要根据研究内容选择相对合适的心肌细胞损伤模型。     

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。     

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.     

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。     

Bufalin,a bufanolide steroid from the parotoid glands of the Chinese toad,inhibits L‐type Ca2+ channels and contractility in rat ventricular myocytes

Bufalin is a bufanolide steroid compound in Chan Su. Chan Su is a traditional Chinese medicine prepared from the dried white secretion of the auricular and skin glands of toads and has been used as an oriental drug. However, the effect of bufalin on cardiac function and its underlying cellular mechanisms remain unclear. Here, we explore the cellular mechanisms of bufalin on myocardial protection via the whole‐cell patch‐clamp recording and video‐based edge detection system. Exposure to bufalin resulted in a concentration‐dependent blockade of I_Ca‐L, with the half‐maximal inhibitory concentration (IC₅₀) of 60 μm and the maximal inhibitory effect of 71.50 ± 2.67%. Bufalin at 100 μm reduced cell shortening by 33.83 ± 4.01%. Bufalin restrained L‐type Ca²⁺ channels conductance, and contractility in rat ventricular myocytes. Thus, the protective effects of bufalin on the heart may be determined by the inhibitory effect on I_Ca‐L and the negative inotropic action caused by the decrease of intracellular Ca²⁺ in rat myocardial cells.     

苓桂术甘汤对慢性心律失常大鼠心肌损伤的保护作用及对Nrf2/HO-1通路的影响

[目的]探讨苓桂术甘汤对慢性心律失常大鼠心肌损伤的保护作用及对核因子E2相关因子2(nuclear factor E2 related factor 2,Nrf2)/血红素氧合酶-1(heme oxygenase-1,HO-1)通路的影响。[方法]45只雄性SD大鼠中随机选择10只作为正常对照组,其余35只经尾静脉注射氯化钡溶液制备慢性心律失常模型,将30只建模成功的大鼠随机分为苓桂术甘汤组、阳性对照组、模型对照组,每组各10只。苓桂术甘汤组大鼠采用苓桂术甘汤灌胃,阳性对照组采用酒石酸美托洛尔灌胃,模型对照组和正常对照组接受等体积0.9%氯化钠注射液灌胃,2次/d,均干预4周。采用心电图检验大鼠造模成功情况,以酶联免疫吸附法检验大鼠血清谷胱甘肽(glutathione,GSH)、谷胱甘肽硫基转移酶(glutathione S-transferase,GST)含量,苏木精-伊红(hematoxylin-eosin,HE)染色观察心肌组织病理变化,DNA缺口末端标记法(TdT-mediated dUTP nick-end labeling,TUNEL)染色检测各组大鼠心肌细胞凋亡情况,实时荧光定量聚合酶链式反应(Real-time fluorescence quantitative polymerase chain reaction,Real-time q PCR)与Western blot检测心肌组织中Nrf2、HO-1基因及蛋白表达水平。[结果]与正常对照组比较,模型对照组、阳性对照组、苓桂术甘汤组GSH和GST含量较低,心肌细胞凋亡率较高,Nrf2、HO-1 mRNA与蛋白相对表达量较高(P0.05)。与模型对照组比较,阳性对照组、苓桂术甘汤组大鼠的GSH和GST含量较高,心肌细胞凋亡率较低(P0.05);与阳性对照组比较,苓桂术甘汤组大鼠的GSH和GST含量较低,心肌细胞凋亡率较高(P0.05)。模型对照组心肌组织水肿、充血严重,肌束紊乱,心肌细胞间隙增宽;阳性对照组、苓桂术甘汤组心肌组织水肿、肌束及心肌细胞间隙明显改善。与模型对照组比较,阳性对照组、苓桂术甘汤组大鼠Nrf2、HO-1 mRNA及蛋白相对表达量均较高(P0.05);与阳性对照组比较,苓桂术甘汤组大鼠Nrf2、HO-1 mRNA及蛋白相对表达量均较低(P0.05)。[结论]苓桂术甘汤可能通过激活Nrf2/HO-1通路,发挥对慢性心律失常大鼠心肌损伤的保护作用。