靶向PUMA的siRNA对缺氧/复氧诱导大鼠心肌细胞凋亡的保护作用

为探讨p53上调凋亡调制物(p53 up-regulated modulator of apoptosis,PUMA)在大鼠心肌细胞缺氧/复氧(hypoxia/reoxygenatio,H/R)损伤中的作用,本研究将靶向PUMA的siRNA(si-PUMA)转染大鼠心肌细胞以建立PUMA沉默表达模型,观察其对心肌细胞H/R损伤的影响.RT-PCR和Western印迹结果表明,最适转染浓度50 nmol/L si-PUMA能靶向抑制H/R损伤心肌细胞的PUMA表达;MTT法检测心肌细胞存活率及培养基乳酸脱氢酶(lactate dehydrogenase,LDH)活性测定结果发现,si-PUMA组细胞存活率较H/R 6 h模型组明显提高,培养液中LDH活性显著降低(P<0.01);分光光度法及Annexin V-FITC/PI联合染色流式细胞凋亡检测结果显示,si-PUMA组caspase-3活性较H/R 6h组明显下调,细胞凋亡率明显降低(P<0.01);RT-PCR结果提示,与H/R6 h组相比,si-PUMA组Bax及Bcl-2表达分别出现显著下调及上调(P<0.05).以上结果表明,靶向PUMA的siRN...     

PUMA对高糖诱导的大鼠H9C2心肌细胞凋亡的作用及机制

目的:观察促凋亡蛋白p53上调凋亡调控因子(PUMA)在高糖所致H9C2心肌细胞凋亡中的作用及机制。方法:H9C2心肌细胞随机分为对照组(使用5.5mmol/L葡萄糖作用于细胞)和高糖组(使用35 mmol/L葡萄糖作用于细胞,HG组)分别刺激6 h, 12 h, 24 h和48 h,每组设复孔5个,TUNEL染色检测细胞凋亡率;RT-PCR及Western blot法分别测定PUMA mRNA及蛋白表达情况;JC-1法检测线粒体膜电位;Western blot测定caspase-3表达和细胞色素c(Cyt C)释放。H9C2细胞随机分为四组,对照组、高糖(35 mmol/L)、HG+si-scramble组(使用si-scramble转染心肌细胞24 h,使用35mmol/L葡萄糖作用于细胞)和Si-PUMA组(使用si-PUMA转染心肌细胞24 h,使用35mmol/L葡萄糖作用于细胞),观察抑制PUMA表达对高糖诱导细胞凋亡率、线粒体膜电位、Cyt C的影响。结果:与对照组相比,高糖刺激心肌细胞组TUNEL染色阳性率、活化caspase-3和PUMA表达明显升高(P<0.0...     

间歇低压低氧预处理对心肌缺血／再灌注损伤及ZFP580表达的影响

目的：探讨间歇性低压低氧（IHH）预处理对大鼠心肌缺血／再灌注（I/R）损伤后血清中心肌酶、心肌梗死的影响及锌指核转录因子ZFP580发挥的作用。方法：32只雄性Wistar大鼠随机分为IHH预处理组和常氧对照组（n=16）。IHH组大鼠置于模拟海拔高度为5000m的低压氧舱中,每天6h,持续42d。两组大鼠经结扎冠状动脉左前降支建立心肌I/R损伤模型后,检测血清中乳酸脱氢酶（LDH）活性及肌酸磷酸肌酶同功酶（CK-MB）浓度,并利用Western blot方法观察各组大鼠心肌组织中ZFP580的表达情况。每组另外8只大鼠经心肌酞菁蓝-TIC染色后比较心肌梗死面积。培养大鼠H9c2心肌细胞,利用慢病毒介导的基因转染实验获得高表达ZFP580的心肌细胞,并进行心肌细胞模拟缺血／再灌注（SI/）损伤实验。利用Annexin V-PE／7-AAD柒色及流式细胞术检测H9c2心肌细胞的凋亡情况。结果：IHH预处理能明显减少心肌I／R损伤后IDH、CK-MB漏出至血清,并明显缩小心肌梗死面积。大鼠经IHH预处理后心肌组织中ZFP580的表达上调,IHH预处理明显上调心肌L／R损伤后心肌组织中ZFP580的表达。高表达ZFP580的H9c2心肌细胞在STIR损伤后细胞凋亡率明显下降。结论：IHH预处理对于心肌I／R损伤具有明显细胞保护作用,其上调的ZFPS80表达具有减少心肌细胞凋亡的作用,ZFP580可能作为心肌细胞内源性抗凋亡分子之一,参与IHH预处理抗心肌I／R损伤的过程。     

褪黑素通过提高p53和Fas的表达促进小鼠肝癌H22细胞凋亡

目的：研究褪黑素（MLT）对小鼠肝癌细胞株H22的促凋亡作用及其机理。方法：采用丫啶橙（AO）染色、培养液乳酸脱氢酶（LDH）活性检测和流式细胞术（FCM）观察MLT的促凋亡作用;采用RT-PCR方法检测MLT处理前后细胞的p53 mRNA、Fas mRNA的水平。结果：AO染色后H22细胞呈现明显核浓缩的凋亡形态;培养液LDH活性检测及FCM分析均提示MLT诱导H22细胞发生凋亡;RT-PCR结果显示p53、Fas表达增强。结论：MLT能促进H22细胞p53和Fas的表达,从而诱导细胞发生凋亡。     

过氧化氢预处理对H9c2心肌细胞氧化应激损伤的保护作用

目的：活性氧介导的氧化损伤是缺血再灌注损伤的重要机制,本研究通过观察H2O2预处理对氧化损伤的H9c2心肌细胞存活率和细胞凋亡的影响,探讨其保护H9c2心肌细胞的作用机制。方法：体外培养H9c2心肌细胞,取对数生长期细胞用于实验研究。建立H2O2预处理抵抗高浓度H：O：诱导的细胞氧化损伤模型,实验分组如下：（1）正常对照组（CTL）;（2）损伤组（INJURY）;（3）预处理组十损伤组（PC）。应用CCK8法检测细胞存活率;试剂盒检测胞内MDA水平和T．sOD活性;Hoechst33258染色观察凋亡形态;Annexin-V／PI双染与流式细胞术检测细胞凋亡率。结果：25vLmol／L的H202预处理90rain能明显地保护H9c2心肌细胞抵抗400μmol／LH2O2诱导的氧化损伤,提高细胞存活率,下调MDA水平,上调SOD活性,抑制细胞凋亡,降低细胞凋亡率。结论：低浓度H2O2预处理能减轻H9c2心肌细胞的氧化损伤,抑制氧化损伤诱导的心肌细胞凋亡,具有很好的抗氧化损伤和抗心肌细胞凋亡的保护作用,其作用机制可能与细胞SOD活性上调有关。H2O2预处理为临床治疗心肌缺血／再灌注损伤提供了一项新策略。     

siRNA沉默SIRT1基因对宫颈癌细胞HeLa增殖和凋亡的影响

化学合成靶向SIRT1基因的小干扰RNA,脂质体法转染人宫颈癌细胞株HeLa,观察小干扰RNA沉默SIRT1基因对HeLa增殖及细胞凋亡的影响。在优化siRNA SIRT1转染条件的基础上,应用RT-PCR和Western blot分别检测各组SIRT1 mRNA、SIRT1蛋白及凋亡相关蛋白的表达;CCK-8法检测细胞增殖抑制率;Hoechst荧光染色法和流式细胞仪检测细胞凋亡。结果表明,siRNA SIRT1转染细胞组SIRT1 mRNA水平和蛋白表达量明显低于对照组;siRNA SIRT1转染组细胞增殖受抑制,细胞凋亡率明显增加;凋亡相关蛋白P53、P21表达上调,Survivin表达下调。上述结果表明:siRNA SIRT1诱导的HeLa细胞凋亡与P53、P21、Survivin通路关系密切,但siRNA SIRT1诱导HeLa细胞凋亡的详尽机制有待进一步研究。     

2类多巴胺受体对心肌缺血后处理保护作用的影响及机制

目的：观察2类多巴胺受体（DR2）在心肌缺血后处理保护中的作用,并探讨其机制。方法：复制原代培养乳鼠心肌细胞缺血后处理模型,细胞随机分为正常组（Control）、缺血/再灌注组（I/R）、缺血后处理组（PC）、缺血后处理＋DR2激动剂组（PC＋Bro）、缺血后处理＋DR2抑制剂组（PC＋Hal）、缺血后处理＋DR2抑制剂＋激动剂组（PC＋Hal＋Bro）。比色法检测细胞培养液乳酸脱氢酶（LDH）、超氧化物歧化酶（SOD）活性和丙二醛（MDA）含量;透射电镜观察细胞超微结构改变;流式细胞仪检测细胞凋亡变化;Western blot方法检测DR2蛋白表达、p-p38和p-JNK的活性。结果：与正常组相比,I/R能够增加DR2蛋白的表达,升高LDH活性和MDA含量,降低SOD活性,加重细胞损伤和细胞凋亡,上调p-p38和p-JNK的活性;与I/R组比较,PC进一步增加DR2蛋白的表达,降低LDH活性和MDA含量,增加SOD活性,减轻细胞损伤和细胞凋亡,下调p-p38和p-JNK的活性,Bro增强了PC的心肌保护作用,Hal则可取消Bro的这种作用。结论：DR2激活通过下调p-p38和p-JNK的活性参与缺血后处理对心肌缺血/再灌注损伤的保护作用。     

EPO对缺血/再灌注损伤大鼠心肌细胞Mfn2蛋白表达及心肌细胞凋亡的影响

目的观察重组人促红细胞生成素（recombinant human erythropoietin,rhEPO）对缺血/再灌注损伤大鼠心肌细胞Mitofusin2（Mfn2）蛋白表达的影响及其抗心肌细胞凋亡的作用。方法选取成年SD大鼠35只,随机分为正常组（Normal）,假手术组（Sham）,缺血再灌注组（I/R）,缺血再灌注EPO治疗组（I/R＋EPO）。各组分别于再灌注3h和24h后,剪取心脏缺血/再灌注损伤区域,用脱氧核苷酸末端转移酶介导的缺口末端标记法（TUNEL）检测心肌细胞凋亡,免疫组化法检测Mfn2蛋白的表达。结果再灌注3h和24h后,与正常组和假手术组相比,I/R组Mfn2蛋白的表达和心肌细胞凋亡均显著增加;与I/R组相比,I/R＋EPO组Mfn2蛋白的表达和心肌细胞凋亡均显著降低。结论EPO可以下调缺血再灌注损伤后心肌细胞Mfn2蛋白的表达,抑制心肌细胞的凋亡。     

多巴胺受体(DR2)激活对乳鼠心肌细胞缺氧/再灌注损伤的保护作用及其机制

目的:观察多巴胺受体(DR2)激活对乳鼠心肌细胞缺氧/再灌注损伤的影响,并探讨其机制。方法:复制原代培养乳鼠心肌细胞缺氧/再灌注损伤模型,细胞随机分为正常组(Control)、缺氧/再灌注组(H/R)、DR2激动剂组(溴麦角环肽,Bro)、抑制剂组(氟哌啶醇,Hal)。倒置显微镜、透射电镜、流式细胞仪检测细胞凋亡情况;检测细胞培养液乳酸脱氢酶(LDH)、超氧化物歧化酶(SOD)活性和丙二醛(MDA)含量;RT-PCR和Western blot方法检测心肌细胞促凋亡因子(Cyt C、caspase-3、caspase-8、caspase-9、Fas及Fas-L)及抑凋亡因子(Bc-l 2)mRNA和蛋白表达。结果:与正常组相比,H/R组细胞凋亡率、LDH活性、MDA含量、促凋亡因子及抑凋亡因子表达均增加,唯有SOD活性降低;与H/R组比较,Bro组可减轻或逆转上述指标的变化;Hal组上述指标变化不明显。结论:DR2激活可抑制缺氧/再灌注所致的乳鼠心肌细胞损伤和凋亡,机制与减少氧自由基有关。     

凋亡诱导因子介导缺氧/复氧致肥大心肌细胞凋亡的作用

心肌细胞凋亡导致心肌组织合胞体功能丧失,最终使代偿性心肌肥大向心力衰竭转化。过去的研究已经确认天门冬氨酸特异性半胱氨酸蛋白酶(caspartate-specificcysteinylproteinase,caspase)依赖机制在心肌细胞凋亡中的作用,但对caspase非依赖机制即凋亡诱导因子(apoptosis-inducingfactor,AIF)在心肌细胞凋亡中的作用尚不明确。本研究应用血管紧张素Ⅱ(0.1μmol/L培养12h)诱导培养的小鼠肥大心肌细胞,利用三气孵箱建立缺氧/复氧模型以模拟缺血再灌注。应用RT-PCR、Westernblot、siRNA基因转染、Hoechst33258染色法检测AIF在mRNA和蛋白质水平的表达及细胞凋亡的变化,分析AIF在缺氧/复氧致肥大心肌细胞凋亡中的意义。结果如下:(1)与对照组比较,缺氧8h组(H8h)和缺氧12h组(H12h)AIFmRNA及蛋白表达水平均显著升高(mRNA:0.52±0.04及0.85±0.10vs0.29±0.08,P<0.05;蛋白质:2.07±0.15和3.12±0.19vs0.29±0.04,P<0.05),即随缺血时间的延长,AIFmRNA及蛋白表达水平均显著增加。(2)与对应单纯缺氧组比较,缺氧后给予复氧刺激,H8h/R组和H12h/R组AIFmRNA及蛋白表达水平均显著升高(mRNA:1.09±0.12和1.41±0.23,P<0.05;蛋白质:4.57±0.25和5.71±0.27,P<0.05)。仅在H8h/R及H12h/R组,可见AIF核转位显著增加。(3)AIFsiRNA转染可显著抑制肥大心肌细胞AIF的表达,对缺氧时细胞凋亡无明显影响(P>0.05),但可显著降低缺氧/复氧诱导的肥大心肌细胞凋亡率(P<0.05)。同时抑制AIF及caspase-3活性,可显著加强单一抑制剂对缺氧/复氧诱导的肥大心肌细胞凋亡的抑制作用。(4)抑制caspase-3活性对缺氧/复氧诱导的AIF核转位无明显影响。上述结果提示,缺氧/复氧时AIFmRNA、蛋白表达和核转位均显著增加,且在缺氧/复氧诱导肥大心肌细胞凋亡中具有重要的作用。     

Regulation of PUMA induced by mechanical stress in rat cardiomyocytes

Background

PUMA (p53-up-regulated modulator of apoptosis), an apoptosis regulated gene, increased during endoplasmic reticulum stress. However, the expression of PUMA in cardiomyocytes under mechanical stress is little known. We aimed to investigate the regulation mechanism of PUMA expression and apoptosis induced by mechanical stress in cardiomyocytes.

Methods

Aorta-caval (AV) shunt was performed in adult Wistar rats to induce volume overload. Rat neonatal cardiomyocytes were stretched by vacuum to 20% of maximum elongation at 60 cycles/min.

Results

PUMA protein and mRNA were up-regulated in the shunt group as compared with sham group. The increased PUMA protein expression and apoptosis induced by shunt was reversed by treatment with atorvastatin at 30 mg/kg/ day orally for 7 days. TUNEL assay showed that treatment with atorvastatin inhibited the apoptosis induced by volume overload. Cyclic stretch significantly enhanced PUMA protein and gene expression. Addition of c-jun N-terminal kinase (JNK) inhibitor SP600125, JNK small interfering RNA (siRNA) and interferon-γ (INF-γ) antibody 30 min before stretch reduced the induction of PUMA protein. Gel shift assay demonstrated that stretch increased the DNA binding activity of interferon regulatory factor-1. Stretch increased, while PUMA-Mut plasmid, SP600125 and INF-γ antibody abolished the PUMA promoter activity induced by stretch. PUMA mediated apoptosis induced by stretch was reversed by PUMA siRNA and atorvastatin.

Conclusions

Mechanical stress enhanced apoptosis and PUMA expression in cardiomyocytes. Treatment with atorvastatin reversed both PUMA expression and apoptosis induced by mechanical stress in cardiomyocytes.     

Effect of miR-499a-5p on damage of cardiomyocyte induced by hypoxia-reoxygenation via downregulating CD38 protein

The aim is to investigate the mechanism of miR-499a-5p on the damage of cardiomyocyte induced by hypoxia/reoxygenation. The activity of lactate dehydrogenase (LDH), apoptosis rate and the expression of miR-499a-5p and cluster of differentiation 38 (CD38) in hypoxia-reoxygenation model cells were detected by LDH Cytotoxicity Assay Kit, flow cytometry, real-time polymerase chain reaction, and Western blot analysis, respectively. Apoptosis, the activity of LDH was detected after overexpression of miR-499a-5p or silencing of CD38 in H9c2 cells. The target relationship between miR-499a-5p and CD38 was verified by Targetscan online prediction and dual-luciferase assay. Apoptosis, the activity of LDH was detected after overexpression of miR-499a-5p and CD38. Apoptosis, the activity of LDH and the expression of CD38 were increased (P < .05) while expression of miR-499a-5p was decreased (P < .05) in hypoxia/reoxygenation model cells. Apoptosis and the activity of LDH in H9c2 cells after overexpression of miR-499a-5p or silence of CD38 were decreased (P < .05). The results of Targetscan online prediction and dual-luciferase assay indicated that CD38 was a potential target gene of miR-499a-5p. Overexpression of CD38 could reverse the inhibition of miR-499a-5p on LDH activity and apoptosis in H9c2 cells. miR-499a-5p could relief the injury of cardiomyocytes induced by hypoxia/reoxygenation via targeting CD38.     

三七皂苷对缺氧复氧心肌细胞损伤保护作用的研究

目的：研究三七皂苷对纯化培养大鼠乳鼠心肌细胞缺氧/复氧损伤的保护作用及机制。方法：采用纯化培养的心肌细胞建立缺氧/复氧损伤模型,测定细胞凋亡率、caspase-3、乳酸脱氢酶（LDH）、丙二醛（MDA）、超氧化物歧化酶（SOD）含量。结果：与正常组比较,模型组LDH、MDA含量、caspase-3活性及细胞凋亡率明显升高（P＆lt;0.01）,SOD活性明显降低（P＆lt;0.01）;三七皂苷组降低LDH、MDA含量、caspase-3活性和细胞凋亡率,提高SOD活性,与缺氧/复氧组比较各实验指标差异均具有显著性（P＆lt;0.05）。结论：三七皂苷对缺氧/复氧心肌细胞损伤有保护作用,作用机制与清除氧自由基,抗脂质过氧化及降低细胞凋亡率有关。     

腺苷对缺氧/复氧心肌细胞的保护作用

本研究旨在探讨腺苷 (adenosine ,ADO)对缺氧 /复氧 (hypoxia/reoxygenation ,H/R)心肌细胞的保护作用及其分子机制。将原代培养的新生大鼠心肌细胞分成H/R对照组和ADO (1 0 μmol/L)保护组。用倒置相差显微镜观察心肌细胞的生长状态。检测两组培养基质乳酸脱氢酶 (LDH)活性和心肌细胞Ca2 + 和丙二醛 (MDA)浓度。用ELISA法检测肿瘤坏死因子 (TNF α)的表达 ,并用凝胶电泳迁移率改变法 (EMSA)测定核因子 (NF κB)结合活性。所得结果如下 :(1)心肌细胞H/R培养后皱缩、变圆 ,伪足减少 ,ADO组心肌细胞的形态变化小于对照组 ;(2 )ADO减少缺氧和复氧期间心肌细胞LDH的漏出 (bothP <0 0 1) ;(3 )ADO降低缺氧和复氧期间心肌细胞内的Ca2 +浓度 (bothP <0 0 1) ;(4)ADO降低缺氧和复氧期间心肌细胞MDA浓度 (bothP <0 0 1) ;(5 )ADO抑制缺氧和复氧期间TNF α的表达 (bothP <0 0 1) ;(6)ADO抑制缺氧和复氧期间心肌细胞NF κB结合活性 (bothP <0 0 1)。以上结果提示 :(1)外源性ADO可减轻心肌细胞的H/R损伤 ;(2 )外源性ADO抑制H/R期间心肌细胞TNF α的表达 ;(3 )外源性ADO可能通过抑制心肌细胞NF κB结合活性下调TNF α的表达     

Leptins and leptin receptor expression in the goldfish (Carassius auratus). Regulation by food intake and fasting/overfeeding conditions

Intermedin (IMD)(1-53) is a novel member of the calcitonin gene-related peptide superfamily and has potent cardioprotective effects against myocardial injury induced by ischemia-reperfusion (I/R). To explore the mechanism of the IMD(1-53) cardioprotective effect, we studied the anti-oxidant effects of IMD(1-53) on myocardial injury induced by I/R in vivo in rat and H(2)O(2) treatment in vitro in rat cardiomyocytes. Compared with sham treatment, I/R treatment induced severe lipid peroxidation injury in rat myocardium: plasma malondialdehyde (MDA) content and myocardial LDH activity was increased by 34% and 85% (all P<0.01); Mn-superoxide dismutase (Mn-SOD) and catalase (CAT) activity was reduced 80% and 86% (all P<0.01), respectively, and the protein levels of the NADPH oxidase complex subunits gp91(phox) and p47(phox) were markedly increased, by 86% (P<0.05) and 95% (P<0.01), respectively; IMD(1-53) treatment ameliorated lipid peroxidation injury: plasma MDA content and myocardial LDH activity was decreased by 30% (P<0.05) and 36% (P<0.01); Mn-SOD and CAT activity was elevated 1.0- and 4.3-fold (all P<0.01), respectively; and the protein levels of gp91(phox) and p47(phox) were reduced, by 28% and 36% (both P<0.05), respectively. Concurrently, IMD(1-53) treatment markedly promoted cell viability and inhibited apoptosis in cardiomyocytes as compared with H(2)O(2) treatment alone. Furthermore, IMD(1-53) increased the ratio of p-ERK to ERK by 66% (P<0.05) as compared with I/R alone, and the protective effect of IMD(1-53) on H(2)O(2)-induced apoptosis was abolished by preincubation with PD98059, a MEK inhibitor. IMD(1-53) may improve the oxidative stress injury induced by I/R via inhibiting the production of reactive oxygen species and enhancing ERK phosphorylation.     

Small interference RNA against PTP-1B reduces hypoxia/reoxygenation induced apoptosis of rat cardiomyocytes

Objective To investigate the effect of siRNA against PTP-1B on neonatal rat cardiac myocyte apoptosis induced by hypoxia-reoxygenation (H/R) and its molecular mechanisms. Methods Isolated neonatal and adult rat cardiac myocytes were cultured for 24 h after PTP-1B siRNA transfection, and with 2, 4 and 6 h of hypoxia followed by 6 h of reoxygenation (H/R). The cardiac myocyte apoptosis induced by the treatments was assessed by TUNEL staining. Levels of PTP-1B and phospho-Akt were determined by Western blot, colorimetric assay kits were used to measure activities of caspase-3 and 8, and co-immunoprecipitation was used to check the amount of PTP-1B bound to FasR. Sodium orthovanadate, a general pharmacological phosphatase blocker and LY294002, an inhibitor of PI3-kinase/Akt pathway, were respectively used to inhibit PTP-1B and Akt activity. Results H/R resulted in severe injury in cultured rat cardiomyocytes and upregulated PTP-1B expression. However, siRNA against PTP-1B significantly decreased the number of apoptotic cardiomyocytes induced by 4H/6R as compared with cells without siRNA treatment (Apoptotic index: 12.1 ± 1.4% vs. 23.2 ± 1.6%, P < 0.05), along with greater phosphorylation of Akt, reduced activities of caspase-3 and 8, and the lower association of PTP-1B with FasR. Vanadate and LY294002 also partly reduced apoptosis of cardiomyocytes induced by 4H/6R. Conclusions PTP-1B is a key regulator of apoptosis of cardiomyocytes induced by H/R, and siRNA against PTP-1B effectively protects cardiomyocytes against H/R injury, the mechanisms of which might be associated with Akt activation, the reduction of both caspase-3 and 8 activities, and the lower amount of PTP-1B bound to FasR.     

PRKAG2-AS1通过AMPK抑制缺氧所致心肌细胞凋亡

目的:探讨PRKAG2-AS1在缺氧所致心肌细胞凋亡中的作用及其可能机制。方法:以人心肌细胞系作为主要研究对象,使用RNA核质分提的方法检测PRKAG2-AS1在细胞中的表达分布模式。将人心肌细胞系分为常氧对照组及低氧组,分别置于常氧环境(21% O2)和低氧环境(1% O2)培养12小时,构建心肌细胞缺氧模型,AnnexinV-FITC/PI流式细胞学检测细胞凋亡,Real-time PCR检测模型中SOD mRNA及PRKAG2-AS1基因表达。对常氧培养条件下心肌细胞通过siRNA及反寡义核苷酸方法分别靶向敲低胞质及胞核内PRKAG2-AS1的表达水平,AnnexinV-FITC/PI流式细胞学检测细胞凋亡,观察PRKAG2-AS1对心肌细胞凋亡的影响;Real-time PCR检测SOD mRNA表达,Western blot检测AMPKγ2亚基蛋白的表达,观察PRKAG2-AS1对SOD mRNA及AMPKγ2蛋白表达的影响。结果:PRKAG2-AS1在心肌细胞胞质及胞核中均有表达,且以胞核为主。PRKAG2-AS1基因表达水平在心肌细胞缺氧模型中明显降低(P<0.05)。对常氧培养条件下心肌细胞,敲低PRKAG2-AS1基因表达,将导致细胞凋亡增加(P<0.05),且敲低胞核中表达细胞凋亡更为明显,同时,敲低PRKAG2-AS1能够引起SOD mRNA表达水平改变(P<0.05),且AMPKγ2蛋白表达水平降低(P<0.05)。结论:PRKAG2-AS1可能通过AMPK途径影响SOD表达,从而调控心肌缺氧损伤中的细胞凋亡。     

内皮素-1预处理对培养乳鼠心肌细胞低氧损伤的保护作用

实验观察了 0 0 1- 1nmol/L内皮素 1(ET 1)预处理对低氧孵育 ( 3 %O2 5 %CO2 ,12h)的培养乳鼠心肌细胞乳酸脱氢酶 (LDH)释放量、培养液上清超氧化物歧化酶 (SOD)活性以及丙二醛 (MDA)含量的影响。用Fluo 3 /AM负载培养的心肌细胞 ,在激光扫描共聚焦显微镜下监测急性低氧的心肌细胞 [Ca2 +]i 的变化和ET 1预处理对低氧所致 [Ca2 +]i 变化的影响。结果如下 :( 1)心肌细胞低氧孵育 12h后 ,培养液上清LDH活力和MDA含量较常氧对照组明显升高 ,分别为 43 3 3± 1 2 1U/Lvs 19 3 3± 1 0 3U/L和 1 71± 0 0 2nmol/Lvs 0 91± 0 0 3nmol/L (P<0 0 1) ,SOD活性为 16 93± 1 11U/ml明显低于常氧对照组的 3 3 48± 1 15U/ml (P <0 0 1) ;0 0 1- 1nmol/LET 1预处理呈浓度依赖性抑制低氧培养心肌细胞LDH释放 ,减少培养液上清MDA含量、提高SOD活性 (P <0 0 1)。 ( 2 )低氧灌流后 2 9± 1 5s (n =2 3 )心肌细胞自发性钙瞬变完全终止 ,[Ca2 +]i 升高了 10 7± 13 2 % (P <0 0 0 1) ;0 0 1- 1nmol/LET 1能明显加快心肌细胞钙瞬变的频率 (P <0 0 1) ;ET 1预处理后低氧所致钙瞬变终止的时间较单纯低氧组明显推迟 ,[Ca2 +]i过度升高被明显减轻 (P <0 0 1)。上述结果表明 ,0 0 1- 1nmol/LET 1预处理可减轻培