对氧磷酶2对氧化低密度脂蛋白诱导的乳鼠心肌细胞损伤的影响

目的 探讨对氧磷酶2(paraoxonase 2,PON2)在氧化低密度脂蛋白(oxidized low density lipoprotein,ox-LDL)诱导的乳鼠心肌细胞(neonatal rat ventricular cells,NRVCs)损伤中的作用及机制.方法 分离SD大鼠(出生1～3d,雌雄不限,共90只)心肌细胞.细胞分为:①对照组(未进行任何干预)、②0.1 μmol/Lox-LDL组(ox-LDL干预24 h)、③10 μmol/Lsalubrinal+ox-LDL组(salubrinal预处理1h后加入ox-LDL干预24 h)、④20 μg/mLPON2+ox-LDL组(PON2预处理1h后加入ox-LDL干预24 h)、⑤2.5μmol/LMn(Ⅲ)TBAP+ ox-LDL组[(Mn(Ⅲ)TBAP预处理1h后加入ox-LDL干预24 h].通过MTT法和Caspase-3/7活性检测试剂盒分别检测细胞活性和细胞凋亡变化(n=6);Western blot检测心肌细胞内质网应激和氧化应激蛋白表达情况(n=4).结果 与对照组相比,ox-LDL明显降低心肌细胞活性[(0.417 ±0.047) vs(O.883 ±0.064),P ＜0.01]显著增加心肌细胞凋亡[(11 505 ±817)vs(6417 ±439),P ＜0.01].与ox-LDL组相比,PON2、salubrinal和Mn(Ⅲ)TBAP干预后,细胞活性显著升高[(0.567 ±0.066) 、0.649 ±0.082) 、0.539 ±0.049) vs0.417 ±0.047),P ＜0.01],细胞凋亡显著下降[(7 776 ±488) 、(7 545 ±547)、(7 960±480)vs (11 505 ±817),P ＜0.01).与对照组相比,ox-LDL显著增加PON2蛋白表达[(0.86 ±0.223) vs (0.561 ±0.13),P ＜0.05]、内质网应激蛋白eIF-2αphox、caspase-12和氧化应激蛋白Nox2/gp91 phox、p47 phox表达[(1.309 ±0.274) vs (0.780 ±0.186) 、(1.294±0.273) vs (0.606 ±0.064) 、(1.342 ±0.274) vs(0.788 ±0.137) 、(1.178 ±0.194) vs (0.629 ±0.125),P＜0.01].与ox-LDL组相比,PON2干预后,PON2蛋白表达明显升高[(1.190 ±0.151) vs (0.860±0.222),P＜0.05];eIF-2αphox 、caspase-12、Nox2/gp91 phox和p47 phox蛋白表达明显降低[(0.924 ±0.170) vs(1.309 ±0.274) 、(0.895 ±0.202) vs (1.294 ±0.273) 、(0.957 ±0.190) vs (1.342 ±0.274) 、(0.799±0.232) vs(1.178 ±0.194),P ＜0.05].与PON2作用类似,salubrinal干预后,eIF-2αphox和caspase-12蛋白表达明显降低[(1.010±0.096) vs(1.309±0.274)、(0.788±0.042)vs(1.294±0.273),P＜0.01],Mn(Ⅲ)TBAP干预后,Nox2/gp91 phox和p47 phox蛋白表达明显降低[(0.898 ±0.190) vs(1.342±0.274) 、(0.769±0.158) vs(1.178 ±0.194),P ＜0.01],二者均显著升高PON2蛋白表达[(1.248±0.259) 、(1.176 ±0.248) vs(0.860 ±0.222),P ＜0.05].结论 PON2可能通过代偿性升高抑制氧化应激和内质网应激而减轻ox-LDL诱导的心肌细胞损伤.     

利多卡因预处理通过影响时钟基因BMAL1改善甲基乙二醛培养的H9C2心肌细胞缺氧/复氧损伤

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20μmol/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。     

达格列净对糖尿病肾脏病的保护作用及机制研究

目的 研究达格列净对糖尿病肾脏病的保护作用及机制。方法 将28只大鼠随机均分为4组：正常组、达格列净干预正常组、糖尿病组、达格列净干预糖尿病组。灌胃法每天给予大鼠达格列净（1mg/kg）8周后,ELISA法检测各组大鼠尿微量白蛋白,WST-1法检测肾脏组织和尿液SOD活性、TBA法检测肾脏组织和尿液MDA含量,RT-PCR检测肾脏组织p22phox、p67phox、Nox2(pg91)mRNA表达,Western blot检测肾脏组织p22phox、p67phox、Nox2(pg91)、磷酸化P38MAPK蛋白表达,PAS染色观察肾脏组织病理形态。结果 相对于正常大鼠,糖尿病大鼠尿微量白蛋白排泄增多,肾脏组织和尿液SOD活性减弱,同时MDA含量增加,肾脏组织p22phox、p67phox、Nox2(pg91)mRNA及蛋白表达,磷酸化P38MAPK蛋白表达增强,肾脏组织病理改变明显;达格列净治疗后,糖尿病大鼠尿微量白蛋白排泄减少,肾脏组织和尿液SOD活性增强,同时MDA含量减少,肾脏组织p22phox、p67phox、Nox2(pg91)mRNA及蛋白表达,磷酸化P38MAPK蛋白表达...     

阿托伐他汀对大鼠脑缺血再灌注PERK/elfR2a通路及Caspase-3表达的影响

目的 研究蛋白激酶R样内质网激酶(PERK)/eIFR2a通路及Caspase-3在大鼠脑缺血再灌注损伤中的作用机制及阿托伐他汀对其的影响。方法采用大脑中动脉线栓塞法制作大鼠脑缺血再灌注模型;随机分为缺血再灌注组、假手术组、阿托伐他汀组、阿托伐他汀+Salubrinal抑制剂组,大体标本采用TTC染色,釆用Western-blot法检测PERK、Caspase-3蛋白表达及eIF2a蛋白磷酸化。结果与假手术组相比,大鼠缺血再灌注后PERK蛋白表达及eIF2a 的磷酸化增加, Caspase-3表达的活性增强(P<0.01);阿托伐他汀干预可以减轻PERK蛋白表达及eIF2a蛋白磷酸化(P<0.05)。给予特异性eIF2a磷酸化抑制剂Salubrinal后可抑制eIF2a的磷酸化及Caspase-3表达的活性(P<0.05),对PERK蛋白表达无影响。形态学上从TTC染色提示:在缺血再灌注组TTC染色可见大片脑梗死组织。Salubrinal抑制剂及阿托伐他汀干预后脑梗死体积明显缩小(P<0.05)。结论内质网应激通过PERK/eIF2a/Caspase-3途径促进细胞凋亡,阿托伐他汀干预可以减轻脑缺血再灌注损伤。     

乳化异氟醚对缺氧/复氧乳鼠心肌细胞的作用及对caspase-3表达的影响

目的 探讨乳化异氟醚(EI)对原代培养乳鼠心肌细胞的作用及对caspase-3表达的影响.方法 原代培养乳鼠离体心肌细胞,建立缺氧/复氧(H/R)损伤模型.将wister乳鼠随机分为4组,正常组(N组)、缺氧/复氧组(H/R组)、H/R+脂肪乳组(F组)、H/R+0.28 mmol/L EI组(EI组),每组8只乳鼠.4组乳鼠均取细胞培养上清液测定乳酸脱氢酶(LDH)活性与肌钙蛋白(cTnI)含量,心肌细胞匀浆后测定超氧化物歧化酶(SOD)活性与丙二醛(MDA)含量;用倒置显微镜观察心肌细胞生长特性及形态的变化.Western blot检测4组乳鼠的caspase-3表达量. 结果 H/R组、F组、EI组3组乳鼠的LDH活性[分别为:(4 355±445)、(4 411±596)和(3 725±873)U/g]、SOD活性[分别为:(14.55±0.47)、(16.24±1.32)和(21.07±5.73)U/ml ]、MDA含量[分别为:(2.01±0.47)、(2.13±0.51)和(1.32±0.31)μmol/g]、cTnI含量[分别为:(1.417±0.135)、(1.412±0.127)和(1.401±0.521)μg/L]与N组[分别为:(1 562±598) U/g、(23.19±0.59)U/ml、(0.23±0.11)μmol/g和(0.265±0.042)μg/L]比较差异均有统计学意义(P<0.05);F组的SOD活性与H/R组比较差异有统计学意义(P<0.05),但LDH活性、MDA含量、cTnI含量与H/R组比较差异均无统计学意义(P＞0.05),EI组LDH活性、SOD活性、MDA含量、cTnI含量与H/R组比较差异均有统计学意义(P<0.05);EI组LDH活性、SOD活性、MDA含量、cTnI含量与F组比较差异均有统计学意义(P<0.05).N组、H/R组、F组、EI组4组乳鼠的Caspase-3表达量[分别为:(0.245±0.028)、(0.642±0.032)、(0.601±0.017)和(0.314±0.027)],组间两两比较差异均有统计学意义(P<0.05).结论 乳化异氟醚对原代培养心肌细胞缺氧/复氧损伤有保护作用,且可能与其抑制caspase-3表达有关.     

VitaePro抑制线粒体通路对心肌细胞缺氧损伤的保护作用

目的：探讨VitaePro对心肌细胞缺氧损伤的保护作用及其机制。方法将大鼠心肌细胞H9c2分为四组：正常对照组(H9c2)、缺氧损伤模型组(Hypoxia+H9c2)、红花油组(Safflower oil+hypoxia+H9c2)和VitaePro组(VitaePro+hypoxia+H9c2)。MTT和流式细胞术分别检测心肌细胞增殖和凋亡情况;Western blot检测线粒体凋亡通路相关蛋白的表达,包括B淋巴细胞瘤-2(Bcl-2)、Bcl-2相关蛋白X (BAX)、凋亡蛋白-3(Caspase-3)和裂解后的Caspase-3(Cleaved caspase-3);试剂盒检测各组心肌细胞硫代巴比妥酸反应物(TBARS)水平、丙二醛（MDA）含量和超氧化物歧化酶(SOD)的活性。最后,Western blot检测心血管损伤标志蛋白的表达,包括心肌肌钙蛋白T (cTnT)、肌红蛋白(Mb)、肌酸激酶同工酶MB (CK-MB)和乳酸脱氢酶(LDH)。结果缺氧损伤模型组与对照组比较,细胞增殖显著下降,凋亡率显著增高(4.2%~14.6%,P<0.05),Bcl-2蛋白的表达明显降低,Bax和Cleaved caspase-3的表达显著升高(P<0.05),TBARS水平和MDA含量升高(P<0.05),SOD活性从44.9 U/mg降低到13.2 U/mg,心血管损伤标志蛋白cTnT、Mb、CK-MB和LDH的表达显著升高(P<0.05)。VitaePro组与缺氧组相比,细胞的增殖升高(P<0.05),凋亡率降低到6.4%,Bcl-2的表达升高,Bax和Cleaved caspase-3的表达明显降低(P<0.05),TBARS水平和MDA含量明显降低(P<0.05),SOD活性增大到41.0 U/mg,cTnT、Mb、CK-MB和LDH的表达显著降低(P<0.05)。结论 VitaePro可以通过抑制线粒体凋亡通路和通过抗氧化作用减轻缺氧诱导的大鼠心肌细胞损伤。     

乳化异氟醚对乳鼠原代培养缺氧/复氧损伤心肌细胞保护效应的最适浓度研究

目的 探讨乳化异氟醚(EI)对乳鼠原代培养缺氧/复氧(H/R)损伤心肌细胞保护效应的最适浓度.方法 原代培养乳鼠心肌细胞,建立体外心肌细胞H/R损伤模型,随机分为13组:正常组(N组),缺氧/复氧组(H/R组),脂肪乳组(F组),按0.28 mmol/L EI的1、2、3、4、5、6、7、8、9、10倍分别分成EI1～ EI10组.各组取细胞培养上清液测定乳酸脱氢酶(LDH)活性和心肌肌钙蛋白I(cTnI)含量,细胞匀浆后测定心肌细胞超氧化物歧化酶(SOD)活性和丙二醛(MDA)含量.结果 与N组比较,各组的LDH、MDA、cTnI均升高(P<0.05),SOD下降(P<0.05).与H/R组比较,EI各组的LDH、MDA、cTnI均降低(P<0.05),SOD升高(P<0.05).与EI6组比较,EI其余各组的LDH、MDA、cTnI均升高(P<0.05),SOD下降(P<0.05).随着EI浓度(倍数递增)的增加,EI1~EI6组的LDH、MDA、cTnI逐渐下降,SOD逐渐升高(P<0.05),EI7~EI10组的LDH、MDA、cTnI逐渐升高,SOD逐渐下降(P<0.05).结论 EI对乳鼠离体心肌细胞H/R损伤具有保护作用,其最佳心肌保护效应浓度为1.68 mmol/L,其机制可能与其抗氧化作用有关.     

乳化异氟醚对乳鼠缺氧/复氧心肌细胞的保护作用及对caspase-3表达的影响

目的 观察乳化异氟醚(8%体积比)对培养乳鼠心肌细胞模拟缺血再灌注损伤后心肌细胞的保护作用并探讨其可能作用机制.方法 利用原代培养的Wistar乳鼠心肌细胞建立模拟心肌缺血再灌注模型,分正常培养组、H/R组、脂肪乳组、乳化异氟醚(终浓度0.28 mmol/L)组.各组心肌细胞作相应分组处理后,利用倒置显微镜观察心肌细胞的生长状态和搏动频率;XTT法测定细胞活力;黄嘌呤氧化酶法测定细胞内超氧化物歧化酶(SOD)活力,硫代巴比妥酸显色法测定细胞内丙二醛(MDA)含量,并测定缺氧复氧后细胞培养液中乳酸脱氧酶(LDH)活性;Western blot法检测caspase-3蛋白表达.结果 与正常培养组比较H/R组细胞SOD下降,MDA、LDH及caspase-3蛋白表达升高(P<0.05).乳化异氟醚组与H/R组比较,心肌细胞SOD活性提高,MDA、LDH及caspase-3蛋白表达下降(P<0.05),且心肌细胞形态及超微结构改善.结论 乳化异氟醚具有明显的抗缺氧复氧损伤、保护心肌细胞的作用,其作用机制可能与抗自由基损伤及抑制caspase蛋白表达水平有关.     

利拉鲁肽对缺氧/复氧条件下乳鼠心肌细胞PI3K途径信号通路的作用

目的 探讨利拉鲁肽对缺氧/复氧(H/R)诱导的心肌细胞损伤是否具有保护作用及其可能机制。方法 成功培养乳鼠心肌细胞作为实验对象,分为5组:正常对照组(A组),单纯H/R组(B组),利拉鲁肽+ H/R组(C组),H/R+利拉鲁肽+LY294002组(D组), H/R+ LY294002组(E组),n=8,对5组分别检测细胞上清液 乳酸脱氢酶(LDH)、丙二醛(MDA)水平以及超氧化物歧化酶(SOD)活性,以流式细胞仪双染法检测各组心肌细胞凋亡率以及凋亡酶半胱氨酸天冬氨酸特异性蛋白酶-3(Caspase-3)活性。结果 与A组比较,B组LDH、MDA、细胞凋亡率、Caspase-3活性明显增高(P<0.01),SOD活性则降低(P<0.01);而与B组比较,C组LDH、MDA、细胞凋亡率、Caspase-3活性则降低(P<0.01),SOD活性升高(P<0.01);与C组比较,给予磷脂酰肌醇3激酶(PI3K)抑制剂LY294002的D组LDH、MDA、细胞凋亡率、Caspase-3活性有所增加(P<0.01), SOD活性降低(P<0.01);E组上述指标的变化与B组相比没有统计学意义(P>0.05)。结论 H/R对心肌细胞造成了损伤,而利拉鲁肽直接作用于心肌细胞,可能通过抗氧化应激损伤、抑制细胞凋亡等机制对心肌细胞产生一定程度的保护作用,而PI3K途径可能与利拉鲁肽的抗凋亡及抗氧化应激作用机制有关。     

转化生长因子-β1预处理调控缺氧诱导因子-1α蛋白表达水平对心肌细胞缺氧/复氧损伤的影响

目的探讨转化生长因子-β1(TGF-β1)预处理调控缺氧诱导因子-1α(HIF-1α)的蛋白表达水平是否可以影响心肌细胞缺氧/复氧损伤。方法建立心肌细胞株H9C2缺氧/复氧损伤模型及缺氧预处理模型,将H9C2心肌细胞随机分为5组:正常对照组(Control组)、缺氧复氧组(H/R组)、缺氧预处理组(HPC组),TGF-β1预处理组(TGF-β1-Pre组)、TGF-β1抑制剂组(SB431542组),各组复氧结束后测定培养液乳酸脱氢酶(LDH)活性、HIF-1α蛋白表达水平、心肌细胞凋亡率。结果Control组、H/R组、HPC组、TGF-β1-Pre组、SB431542组的LDH活性(U/L)分别为(201.2±48.9)、(936.6±93.7)、(727.0±75.9)、(747.3±63.1)、(957.3±55.3);心肌细胞凋亡率(%)分别为(25.5±3.2)、(71.8±5.5)、(42.8±6.1)、(54.1±4.1)、(82.8±9.7),与H/R组比较,HPC组、TGF-β1-Pre组的LDH活性、心肌细胞凋亡率显著降低(P0.05),HIF-1α蛋白表达水平升高(P0.05);与HPC组比较,TGF-β1-Pre组各项指标差异均无统计学意义(P0.05)。结论不论在常氧条件还是在缺氧环境下,TGF-β1均可以增加HIF-1α的蛋白表达水平,并且在缺氧复氧诱导所致的心肌细胞损伤中发挥抗凋亡作用,这种作用与调控HIF-1α的蛋白水平有关。     

穿山龙多糖影响NADPH氧化酶/ROS信号通路抗H2O2诱导的HUVECs细胞损伤作用研究

目的 检测穿山龙多糖(RDNP)是否可以通过影响NADPH氧化酶/ROS信号通路对H2O2诱导的人脐静脉内皮细胞(HUVECs)氧化损伤产生保护作用.方法 H2O2作用HUVECs 4 h造成损伤,分别给予25、50、100、200、400、800 μg/mL RDNP进行干预,选取适当浓度进行后续实验.采用MTT法测定细胞活力;试剂盒检测 LDH、MDA、SOD、T-AOC、GSH-Px、ROS水平;Western Bolt及 qRT-PCR法检测Nox4、p22phox的蛋白及mRNA表达.结果 加入50、100和200 μg/mL浓度的RDNP与H2O2模型组间相比,活力增加,差异有统计学意义(P<0.05或P<0.01).因此选择50、100、200 μg/mL RDNP剂量组进行实验.不同浓度RDNP均可以显著改善H2O2损伤,使细胞形态逐渐趋于正常,以200 μg/mL RDNP给药组的效果最为显著.RDNP可以降低H2O2损伤HUVECs模型中LDH、MDA及ROS的水平,并增强细胞内SOD、 GSH-Px、T-AOC活力;且从mRNA水平及蛋白水平抑制Nox4、p22phox的表达.结论 RDNP可以通过干扰NADPH氧化酶/ROS信号通路抑制H2O2造成的HUVECs氧化损伤,保护内皮细胞.     

NADPH氧化酶在人真皮成纤维细胞氧化应激损伤中的作用

目的探讨NADPH氧化酶在人真皮成纤维细胞氧化应激损伤中的作用。方法H2O2 构建氧化应激模型,将实验分为正常 组、氧化损伤组和NADPH氧化酶抑制剂（DPI）组,MTT检测细胞活力,DCFH-DA 荧光探针检测细胞内活性氧（ROS）改变, Western blot分析NADPH氧化酶胞膜亚基gp91phox表达变化。结果H2O2 对成纤维细胞的氧化损伤呈时间和浓度依赖,H2O2 700 μmol/L处理24 h后细胞活力下降约40%（P<0.05）,ROS升高2倍（P<0.05）。而抑制剂组细胞活力较氧化损伤组增加20% （P<0.05）,ROS下降至正常水平（P<0.05）。Western blotting结果显示氧化损伤组gp91phox表达随H2O2 浓度逐渐升高,而抑制 剂组表达接近正常水平。结论H2O2 可通过影响NADPH氧化酶特别是胞膜亚基gp91phox引发成纤维细胞氧化损伤。     

Role of PERK/eIF2α/CHOP Endoplasmic Reticulum Stress Pathway in Oxidized Low-density Lipoprotein Mediated Induction of Endothelial Apoptosis

Objective PERK/eI F2α/CHOP is a major signaling pathway mediating endoplasmic reticulum(ER) stress related with atherosclerosis.Oxidized LDL(ox-LDL) also induces endothelial apoptosis and plays a vital role in the initiation and progression of atherosclerosis.The present study was conducted to explore the regulatory effect of ox-LDL on PERK/e IF2α/CHOP signaling pathway in vascular endothelial cells.Methods The effects of ox-LDL on PERK and p-e IF2α protein expression of primary human umbilical vein endothelial cells(HUVECs) were investigated by Western blot analysis.PERK gene silencing and selective eI F2α phosphatase inhibitor,salubrinal were used to inhibit the process of ox-LDL induced endothelial cell apoptosis,caspase-3 activity,and CHOP mR NA level.Results Ox-LDL treatment significantly increased the expression of PERK,PERK-mediated inactivation of e IF2α phosphorylation,and the expression of CHOP,as well as the caspase-3 activity and apoptosis.The effects of ox-LDL were markedly decreased by knocking down PERK with stable transduction of lentiviral sh RNA or by selective eI F2α phosphatase inhibitor,salubrinal.Conclusion This study provides the first evidence that ox-LDL induces apoptosis in vascular endothelial cells mediated largely via the PERK/eI F2α/CHOP ER-stress pathway.It adds new insights into the molecular mechanisms underlying the pathogenesis and progression of atherosclerosis.     

促红细胞生成素对缺氧复氧心肌细胞的保护作用及其机制

目的探讨促红细胞生成素(EPO)对缺氧复氧(H/R)心肌细胞是否具有保护作用及其机制。方法以乳鼠心肌细胞株(H9C2细胞)为研究对象,将其分为对照组、H/R组及EPO干预组。其中对照组常规培养;H/R组缺氧2 h后复氧24 h;EPO干预组在缺氧2 h后加入不同浓度的EPO(5、10、20 IU/ml)处理,然后复氧24 h。培养结束后分别检测各组细胞上清液中乳酸脱氢酶(LDH)浓度,使用MTS法检测细胞存活率,使用Western blot检测细胞内Cleaved Caspase-3表达变化,使用线粒体和胞浆蛋白制备试剂盒分离线粒体和胞浆蛋白,使用Western blot分别检测线粒体和胞浆内Omi/HtrA2蛋白表达变化。结果与对照组比较,H/R组细胞存活率明显下降,细胞上清液LDH释放明显增加,细胞内Cleaved Caspase-3表达增强,胞浆内Omi/HtrA2蛋白表达增强,差异均有统计学意义(P0.05);而与H/R组相比,EPO干预组细胞存活率上升,细胞上清液LDH释放降低,Cleaved Caspase-3表达减弱,胞浆内Omi/HtrA2蛋白表达减少,差异均有统计学意义(P0.05),但各指标均未恢复至对照组水平。结论 H/R可诱发心肌细胞凋亡,EPO可减轻H/R诱导的心肌细胞凋亡,其机制可能为抑制线粒体内Omi/HtrA2蛋白的转位,从而抑制Caspases通路激活有关。     

Protective Effects of Salubrinal on Liver Injury in Rat Models of Brain Death

Background:

Previous studies have indicated that endoplasmic reticulum stress participates in and mediates liver injury and apoptosis in brain-dead (BD) rats. In this study, we observed the effect of salubrinal (Sal, Sigma, USA) on liver cells in BD rats and explored its relevant mechanisms.

Methods:

Thirty Sprague–Dawley rats were equally randomized into three groups: BD group, Sal group, and DMSO group. The BD models were established by increasing intracranial pressure in a modified, slow, and intermittent way. In the drug groups, Sal was administered 1 h before the induction of BD. After modeling was completed, the blood and liver samples were harvested. CHOP and Caspase-12 mRNA expression was detected using quantitative polymerase chain reaction. PKR-like ER kinase (PERK), P-eukaryotic translation initiation factor 2α (eIF2α), eIF2α, CHOP and caspase-12 expression was detected using western blotting (WB). CHOP and caspase-12 distribution and expression in liver tissues were determined using immunohistochemistry (IHC). Alanine aminotransferase and aspartate aminotransferase level were detected using an automatic biochemical analyzer. Hepatic cell apoptosis was detected using TUNEL. The results were analyzed using Quantity-one v4.62 software (Bio-Rad, USA).

Results:

CHOP and caspase-12 expression and PERK, eIF2α, and P-eIF2α protein expression showed no significant difference between BD group and DMSO group. Compared with BD group, Sal group had a significantly higher P-eIF2C level and a lower P-PERK level 2 h and 6 h after BD (P < 0.05). However, eIF2α expression showed no significant difference (P > 0.05). After the Sal treatment, CHOP and caspase-12 mRNA expression significantly decreased 4 h after BD (P < 0.05). WB and IHC indicated that CHOP and caspase-12 expression also significantly decreased after Sal treatment. Sal was associated with improved liver function and decreased hepatic cell apoptosis.

Conclusions:

Sal can significantly reduce apoptosis in hepatic cells of BD rats. This protective effect may be achieved via the PERK-eIF2α signaling pathway.     

Calcineurin is involved in cardioprotection induced by ischemic postconditioning through attenuating endoplasmic reticulum stress

Background  Ischemic postconditioning (I-postC) is a newly discovered and more amenable cardioprotective strategy capable of protecting the myocardium from ischemia/reperfusion (I/R) injury. Endoplasmic reticulum (ER) is a principal site for secretary protein synthesis and calcium storage. Myocardial I/R causes ER stress and emerging studies suggest that the cardioprotection has been linked to the modulation of ER stress. The aim of the present study was to determine whether cardioprotection of I-postC involves reduction in ER stress through calcineurin pathway.

Methods  In the in vivo model of rat myocardial I/R, myocardial infarct size was measured by triphenyltetrazolium chloride (TTC) staining and apoptosis was detected using terminal eoxynucleotidyl transferase-mediated deoxyuridine triphosphate nick-end labeling (TUNEL) assay. Expression of calreticulin, C/EBP homologous protein (CHOP), caspase-12, and activation of caspase-12 in myocardium were detected by Western blotting. The activity and expression of calcineurin in myocardium were also detected.

Results  I-postC protected the I/R heart against apoptosis, myocardial infarction, and leakage of lactate dehydrogenase (LDH) and creatine kinase-MB (CK-MB). I-postC suppressed I/R-induced ER stress, as shown by a decrease in the expression of calreticulin and CHOP, and caspase-12 activation. I-postC downregulated calcineurin activation in myocardium subjected to I/R.

Conclusion  I-postC protects myocardium from I/R injury by suppressing ER stress and calcineurin pathways are not associated with the I-postC-induced suppression of ER stress-related apoptosis.

     

Normobaric hyperoxia protects the blood brain barrier through inhibiting Nox2 containing NADPH oxidase in ischemic stroke

ABSTRACT: Normobaric hyperoxia (NBO) has been shown to be neuro- and vaso-protective during ischemic stroke. However, the underlying mechanisms remain to be fully elucidated. Activation of NADPH oxidase critically contributes to ischemic brain damage via increase in ROS production. We herein tested the hypothesis that NBO protects the blood-brain barrier (BBB) via inhibiting gp91phox (or called Nox2) containing NADPH oxidase in a mouse model of middle cerebral artery occlusion (MCAO). Wild-type C57/BL6 mice and gp91phoxknockout mice were given NBO (95% O2) or normoxia (21% O2) during 90-min MCAO, followed by 22.5 hrs of reperfusion. BBB damage was quantified by measuring Evans blue extravasation. The protein levels of matrix metalloproteinase-9 (MMP-9), tight junction protein occludin and gp91phox were assessed with western blot. Gel zymography was used to assess the gelatinolytic activity of MMP-9. In the wild type mice, cerebral ischemia and reperfusion led to remarkable Evans blue extravasation, significantly increased gp91phox and MMP-9 levels and decreased occludin levels in the ischemic brain tissue. In gp91phox knockout mice, the changes in Evans blue extravasation, MMP-9 and occludin were at much smaller magnitudes when compared to the wild type. Importantly, NBO treatment significantly reduced the changes in all measured parameters in wild type mice, while did not cause additional reductions in these changes when gp91phox was knocked out. These results indicate that activation of Nox2 containing NADPH oxidase is implicated in the induction of MMP-9, loss of occludin and BBB disruption in ischemic stroke, and inhibition of Nox2 may be an important mechanism underlying NBO-afforded BBB protection.     

血管紧张素1-7对血管紧张素Ⅱ诱导的SD大鼠心室成纤维细胞的影响

目的 在血管紧张素Ⅱ(angiotensinⅡ,AngⅡ)存在情况下,探讨血管紧张素1-7(angiotensin1-7,Ang1-7)对SD大鼠心室成纤维细胞的影响.方法 采用新生1～3d的SD乳鼠,用胰蛋白酶和Ⅱ型胶原酶消化心室,采用差速贴壁法获取成纤维细胞,将细胞完全随机化分组为对照组(不予处理)、AngⅡ组、Ang1-7组、AngⅡ+Ang1-7组(先用Ang1-7预处理30 min,再加入AngⅡ处理).采用免疫荧光鉴定细胞,CCK-8检测细胞增殖,Western blot检测细胞Rac1、Rad、gp91 phox(Nox2)、P65、结缔组织生长因子(connective tissue growth factor,CTGF)蛋白的表达,实时荧光定量PCR测定Ⅰ型、Ⅲ型胶原蛋白(Col Ⅰ、ColⅢ)和纤维连接蛋白(fibronectin) mRNA的表达.结果 AngⅡ能够促进SD大鼠心室成纤维细胞增殖,Ang1-7能减弱AngⅡ的促增殖作用(P＜0.05);与对照组比较,AngⅡ组Rac1、Nox2、P65、CTGF表达增加,Rad表达下降,Col Ⅰ、ColⅢ、fibronectin转录增加(P＜0.05);与AngⅡ组比较,AngⅡ+Ang1-7组Rac1、Nox2、P65、CTGF表达减少,Rad表达升高,Col Ⅰ、ColⅢ、fibronectin转录下降(P ＜0.05);Ang1-7组上述各项指标与对照组比较,差异无统计学意义(P＞0.05).结论 AngⅡ存在时,Ang1-7对心室成纤维细胞具有保护作用.Ang1-7通过调节Rac1、Rad及下游蛋白的表达,能够抑制成纤维细胞合成细胞外基质.