脑脉通对老龄大鼠脑缺血/再灌注纤溶酶原激活系调节作用的影响

目的 研究脑脉通对老龄大鼠脑缺血／再灌注（I／R）纤溶酶原激活系词节作用的影响。方法 采用线栓法复制局灶性脑I／R模型，将老龄大鼠分为假手术组、模型组、脑脉通组、尼莫地平组，后三组又分为脑缺血3h和I／R6、12、24h、3、6d组。采用电镜、免疫组化和酶谱分析等法，观察各组脑徽血管结构、纤溶酶原激活系的变化。结果 与假手术组比较，模型组脑徽血管病理损伤明显，t-PA（I3h-I／R6d）、u-PA（I／R12h-6d）、PAI-1（yR6h-3d）表达水平显著增强。与模型组比较，脑脉通组徽血管病理损伤明显改善，t-PA（I／R6h-3d）、u-PA（I／R12h-3d）的蛋白表达显著降低和PAI-1（I／R12h-3d）的蛋白表达显著增强。各组PAI-l的酶谱分析比较，其量的变化与免疫表达结果基本一致。结论 脑脉通对老龄大鼠脑VR徽血管基底膜损伤的保护作用与其对纤溶酶原激活系调节有关。     

西维来司钠对大鼠脑缺血再灌注损伤的保护作用

目的 探讨西维来司钠(ONO-5046)对大鼠全脑缺血再灌注(I/R)损伤的保护作用及其机制.方法 SD大鼠随机分为假手术组、I/R组和I/R+ONO-5046组,I/R组和I/R+ONO-5046组根据再灌注时间的不同分为6、12、24、48 h四个亚组.采用四血管阻断法制备I/R模型,缺血15 min,I/R+ONO-5046组于再灌注时经股静脉持续给予 ONO-5046 2 mg·kg-1·h-1,假手术组和I/R组给予生理盐水.观察大鼠脑组织病理学变化,并检测中性粒细胞弹性蛋白酶(NE)、丙二醛 (MDA)含量及超氧化物歧化酶(SOD)、肿瘤坏死因子-α(TNF-α)活性.结果 I/R后,NE含量随再灌注时间延长而不断增强(P＜0.05或P＜0.01),TNF-α表达量也增加并于再灌注12 h达最高峰(P＜0.01).ONO-5046组显著降低缺血再灌注后脑组织NE、MDA含量,升高SOD活性以及减少TNF-α表达,明显改善脑组织病理形态.结论 ONO-5046对脑缺血-再灌注损伤有明显的保护作用,其机制可能与降低NE、MDA含量,升高SOD活性及下调TNF-α阳性表达细胞有关.     

炎症因子在尿毒症大鼠脑缺血再灌注损伤中的作用

目的观察尿毒症大鼠脑缺血再灌注(I/R)后炎症因子的动态变化。方法清洁级健康雄性Wistar大鼠30只,随机分为单纯尿毒症组(CRF组)6只、尿毒症合并脑I/R组(CRF+I/R组)24只,制备尿毒症模型,成模后,再取同样大鼠30只,随机分为正常对照组6只、单纯脑I/R组24只。将I/R组和CRF+I/R组大鼠再制作大脑中动脉栓塞模型,脑缺血2h后再灌注,按再灌注后不同时间点(0、2、12、24h)I/R组、CRF+I/R组又分为4个亚组,每个亚组6只。I/R组和CRF+I/R组按再灌注后的时间点取材,正常对照组在饲养3～7d后取材,CRF组在成模后0～3d取材,RT-PCR法检测脑组织中TNF-α、IL-1β、IL-6mRNA表达情况。结果 TNF-αmRNA:正常对照组与CRF组大鼠脑组织TNF-αmRNA的表达差异不显著(P0.05),CRF组大鼠TNF-αmRNA的表达较I/R组各时间点均降低(P0.05);脑I/R两组大鼠TNF-αmRNA在2h时间点表达最强,此后逐渐下降;CRF+I/R组大鼠各时间点TNF-αmRNA的表达均较CRF组、I/R组升高(P0.05)。IL-1βmRNA、IL-6mRNA:CRF组大鼠IL-1βmR-NA、IL-6mRNA的表达均较正常对照组升高,但差异不显著(P0.05);与I/R组各时间点相比,CRF组大鼠IL-1βmRNA、IL-6mRNA的表达均明显偏低(P0.05);脑I/R两组大鼠脑组织中IL-1β、IL-6mRNA表达随再灌注时间延长逐渐升高,至24h达高峰;与I/R组和CRF组相比,CRF+I/R组各时间点IL-1βmRNA和IL-6mRNA表达均显著升高(P0.05)。结论炎症因子参与了尿毒症大鼠的脑I/R损伤,提示尿毒症的微炎症状态对神经系统具有一定的影响。     

重组组织型纤溶酶原激活剂联合替罗非班对急性脑梗死大鼠血脑屏障相关指标的影响

目的探讨重组组织型纤溶酶原激活剂(rt-PA)阿替普酶联合替罗非班对急性大脑中动脉栓塞性脑梗死大鼠血脑屏障通透性及脑组织盘状结构域受体1(DDR1)、基质金属蛋白酶9(MMP-9)、环腺苷酸应答元件结合蛋白(CREB)、闭合蛋白5的影响。方法选择SD大鼠240只,随机分为假手术组、模型组、rt-PA组和rt-PA联合替罗非班组(联合组),每组60只,制备大脑中动脉栓塞模型,造模后3 h假手术组和模型组注射生理盐水,rt-PA组和联合组注入rt-PA 5 mg/kg,3 h后联合组注射5 mg/kg盐酸替罗非班注射液,记录相对表观弥散系数(rADC);检测脑源性神经生长因子(BDNF)、Bcl-2及磷酸化蛋白激酶(p-Akt)等表达。结果与假手术组比较,其他3组脑梗死灶体积、出血评分、神经功能缺损评分及血脑屏障通透性、BDNF及联合组闭合蛋白5表达明显升高,模型组和rt-PA组血管完全再通率、rADC、闭合蛋白5及其他3组磷酸化CREB、Bcl-2、p-Akt表达明显降低(P0.05)。联合组基底膜边缘光滑,可见紧密连接,其出血评分明显低于rt-PA组[(1.4±0.4)分vs(2.2±0.4)分,P=0.000],血管完全再通率、rADC、脑组织磷酸化CREB、BDNF、Bcl-2、p-Akt及闭合蛋白5表达明显高于模型组和rt-PA组(P0.05),脑梗死灶体积、神经功能缺损评分、血脑屏障通透性、DDR1及MMP-9表达明显低于模型组和rt-PA组(P0.05)。结论 rt-PA联合替罗非班可抑制DDR1过表达下调MMP-9表达,激活Akt/CREB通路,上调BDNF、Bcl-2表达,促进闭合蛋白5上调,使内皮细胞保持完整性,并维持血脑屏障通透性。     

姜黄素对脑缺血再灌注损伤大鼠MMP-2活性和血脑屏障通透性的影响

目的探讨姜黄素降低脑缺血再灌注损伤大鼠血脑屏障通透性及减轻脑水肿的作用及机制。方法将90只SD大鼠随机分为假手术组(n=30)、缺血再灌注组(n=30)、姜黄素治疗组(n=30)。以线栓法制备局灶性脑缺血再灌注损伤大鼠模型,腹腔注射姜黄素,各组于脑缺血再灌注后24 h、48 h、96 h用免疫组织化学方法观察损伤侧脑组织基质金属蛋白酶(MMP)-2活性及层黏连蛋白表达的变化。比色法测定损伤侧脑组织含有伊文思蓝(EB)的量,动态观察该侧血脑屏障通透性变化。结果随着缺血再灌注时间逐渐延长,MMP-2表达能力、EB含量均逐渐增加,48 h达峰,层黏连蛋白的表达逐渐下降,各组之间表达具有统计学差异(P0.05);姜黄素治疗组MMP-2表达、EB含量在各个时间点明显低于缺血再灌注组,同时层黏连蛋白的表达增加(P0.05)。结论姜黄素可抑制脑缺血再灌注损伤大鼠MMP-2的表达,增加层黏连蛋白的表达,降低血脑屏障通透性,从而减轻脑水肿。     

糖尿病脑梗死大鼠在不同时间窗溶栓后MMP-9的表达变化

目的探讨糖尿病脑梗死大鼠在不同时间窗使用重组组织型纤溶酶原激活物(rt-PA)溶栓治疗后的疗效,及其并发症出血性转化的内在机制。方法健康成年雄性Wistar大鼠120只,体重200g～250g,随机分为单纯脑梗死(CI)组、糖尿病(DM)合并CI组、假手术组。各组均在2h和4h给予rt-PA或生理盐水溶栓,溶栓24h后灌注固定取脑,分别行脑组织含水量计算、伊文思蓝(EB)测定血脑屏障通透性、免疫组织化学法测定基质金属蛋白酶-9(MMP-9)的表达。结果 DM合并CI 4h组较单纯CI 4h组脑组织含水量显著增加、血脑屏障通透性增加、MMP-9阳性表达显著升高(P<0.01)。结论 DM+CI大鼠3h以内行rt-PA溶栓治疗有效,而3h以外溶栓治疗后脑水肿明显,血脑屏障破坏严重,其机制可能是通过上调MMP-9的表达来实现的。     

肢体缺血后处理对大鼠脑缺血再灌注后血脑屏障的保护作用

目的探讨肢体缺血后处理(LPostC)是否通过减轻脑缺血再灌注(I/R)后血脑屏障(BBB)的损伤发挥脑保护作用。方法 45只雄性SD大鼠随机分为假手术(Sham)组、I/R组和LPostC组,每组15只。采用石蜡线栓法建立大脑中动脉I/R模型。双侧股动脉夹闭5 min,松开5 min,如此循环3次,制备LPostC模型。再灌注24 h后,干湿法测定脑组织含水量;采用2,3,5-氯化三苯基四氮唑(TTC)法计算脑梗死体积;根据伊文斯兰(EB)渗出量评判BBB通透性;Western印迹法测定闭锁小带蛋白(ZO)-1和水通道蛋白(AQP)-4的表达。结果与Sham组比较,I/R组脑组织含水量、EB渗出量明显增加,ZO-1表达明显降低,AQP-4表达明显增加(P0.05);与I/R组比较,LpostC组脑梗死体积明显缩小,脑组织含水量、EB渗出量明显减少,ZO-1表达明显增加,AQP-4表达明显降低(P0.05)。结论 LPostC对脑I/R损伤具有神经保护作用,可能与其促进ZO-1表达、阻抑AQP-4表达、减轻BBB损害有关。     

心脑舒通对大鼠脑缺血再灌注损伤缺血周边区微血管新生及Ang/Tie系统表达的影响

目的观察心脑舒通胶囊对大鼠局灶性脑缺血再灌注(I/R)损伤缺血周边区脑组织微血管新生及血管生成素(Ang)/酪氨酸激酶受体(Tie)系统表达的影响。方法随机分为假手术组、脑I/R损伤模型组、心脑舒通胶囊(14、28、56 mg/kg)组,采用线栓法制备大鼠大脑中动脉阻塞(MCAO)缺血再灌注模型,缺血90 min后再灌注,分别于造模前30 min、缺血6 h、缺血24 h,每日给药1次,连续7 d。于灌注24 h、7 d后行神经功能评分,末次给药1 h后用水合氯醛(350 mg/kg)麻醉并断头取脑组织,采用Western印迹法测定I/R大鼠皮层缺血周边区Ang1、Ang2、Tie2表达,激光扫描共聚焦显微镜观察脑组织微血管形态及血流灌注量。结果与模型组比较,心脑舒通组大鼠神经功能改善,皮层缺血周边区微血管的数量较多(P0.01,P0.05),Ang1、Tie2蛋白表达量增多(P0.01,P0.05),Ang2蛋白表达量较少(P0.05)。结论心脑舒通可调节大鼠Ang/Tie系统的表达,促进脑缺血后微血管新生,有利于脑缺血后神经功能的恢复。     

DMOG稳定缺血/再灌注心肌组织低氧诱导因子-1α表达时间规律的研究*

目的 观察二甲氧乙二酰甘氨酸（DMOG）预处理对大鼠缺血再灌注（I/R）心肌组织中低氧诱导因子-1α（HIF-1α）表达的影响,探讨DMOG稳定HIF-1α表达的时间规律。方法 雄性Wistar大鼠随机分为假手术组（Sham组）、心肌缺血再灌注组（MI/R组）、DMOG+MI/R组、YC-1+MI/R组（YC-1为HIF-1α抑制剂）。建立心肌缺血/再灌注模型,心肌缺血45 min,再灌注0 h、3 h、6 h、9 h四个时间点。留取心脏左室前壁标本,分别采用Western blot和Real-time PCR法检测心肌组织中HIF-1α 的蛋白与mRNA表达水平。结果 ①再灌注相同时间点,D+MI/R组的HIF-1α蛋白表达量均明显高于MI/R组;在观察时间内,D+MI/R组的HIF-1α蛋白表达量呈现出先增高、后降低的趋势,并且在再灌注3h时达峰值（P<0.05）。②HIF-1α的mRNA表达量在不同组间及再灌注各个时间点均无明显差异（P?0.05）。结论 DMOG预处理能够稳定心肌I/R时HIF-1α的蛋白表达量,峰值出现于再灌注3h,而对HIF-1α的mRNA表达量无明显影响,表明这种作用主要发生于蛋白合成过程,而非基因转录水平。     

脑脉通对老龄大鼠脑缺血再灌注血-脑脊液屏障损伤的保护作用

目的研究脑脉通对老龄大鼠脑缺血再灌注（1／R）血-脑脊液屏障（BBB）损伤的保护作用。方法采用线栓法复制局灶性脑缺血模型，分为假手术组、模型组、脑脉通组、尼莫地平组，后3组又分为脑缺血（I）3h和I／R6、12、24h,3、6d时间点。观察脑组织含水量、病理变化、免疫球蛋白（IgG）表达。结果模型组脑组织含水量升高，IgG漏出增加，BBB通透性增加。脑脉通降低脑组织含水量（I／R24h、3d）、减少IgG漏出（I／R24h～6d）、降低BBB通透性。结论脑脉通改善I／R脑损伤作用显著，其机制可能与改善BBB通透性、降低脑水肿有关。     

大鼠局灶性脑缺血后血脑屏障葡萄糖转运蛋白1表达的变化

目的研究局灶性脑缺血后血脑屏障葡萄糖转运蛋白1(GLUT1)表达的变化。方法采用线栓法制作大鼠大脑中动脉闭塞模型,用免疫组化方法观察脑缺血后1小时、3小时、6小时、12小时、1天、2天、3天、7天时血脑屏障GLUTl表达的动态变化。结果脑缺血后3小时血脑屏障GLUT1的表达开始增加．以后逐渐升高,1天时达高峰,2天时下降．7天时与假手术组比较无显著差异。结论脑缺血后血脑屏障GLUT1的表达增加;此对缺血脑组织具有保护作用。     

花姜酮对胰腺癌细胞迁移和侵袭的影响及机制的研究

目的:探讨花姜酮(zerumbone)对人胰腺癌细胞株BxPC-3和Panc-1迁移和侵袭的影响及其相关基因的表达。方法:以BxPC-3和Panc-1为研究对象,通过四甲基偶氮唑盐(MTT)实验选择毒性较小的花姜酮浓度,用细胞划痕实验、Transwell小室迁移和侵袭实验检测药物对细胞迁移和侵袭能力的影响,蛋白质印迹(Western blot)检测各细胞组CXC族趋化因子受体4(CXCR4)、促分裂原活化蛋白酶激酶1/2(MEK1/2)、磷酸化MEK 1/2(p-MEK1/2)、细胞外调节激酶1/2(ERK1/2)、磷酸化ERK1/2(p-ERK1/2)蛋白表达变化。结果:花姜酮对BxPC-3和Panc-1细胞的生长均有抑制作用,且随着药物浓度的增高和作用时间的延长而增强(P<0.05)。低浓度药物作用后BxPC-3和Panc-1的划痕迁移率都低于对照组(P<0.05)。与对照组相比,Transwell迁移和侵袭实验中BxPC-3和Panc-1用药组的平均穿膜细胞数均减少(P     

三磷酸腺苷后处理对兔心肌缺血再灌注损伤保护作用的研究

目的观察ATP后处理对再灌注损伤挽救激酶信号通路中的蛋白激酶B(Akt)及细胞外信号调节激酶(ERK1/2)表达的影响,探讨ATP后处理的心血管保护效应及可能机制。方法选择48只健康新西兰白兔,随机分为缺血再灌注组(再灌注组)、ATP后处理组(后处理组)、磷脂酰肌醇3激酶(PI3K)抑制剂Wortmannin+ATP后处理组(Wortmannin+ATP组)、ERK1/2抑制剂PD98059+ATP后处理组(PD98059+ATP组),每组12只。建立兔急性心肌缺血再灌注模型。实验终点检测各组心肌梗死面积、细胞凋亡指数,Western blot法检测心肌p Akt,p ERK1/2蛋白表达。结果后处理组心肌梗死面积、细胞凋亡指数明显低于再灌注组(P<0.01)。Western blot检测显示,后处理组p-Akt、p-ERK1/2表达水平明显高于再灌注组(P<0.05)。结论 ATP后处理可以减轻兔缺血再灌注心肌的梗死面积,降低细胞凋亡指数,同时上调p Akt和p-ERK1/2的表达,提示PI3K/Akt及ERK1/2信号通路参与了ATP后处理对兔缺血再灌注心肌的保护作用。     

Alterations in the fibrinolytic system components during acute myocardial infarction

The purpose of this study was to evaluate the changes in tissue-plasminogen activator (t-PA), plasminogen activator inhibitor - type 1 (PAI-1) and D-dimer (DD) antigen plasma levels in acute myocardial infarction (AMI) patients after thrombolytic therapy with two different thrombolytic agents, rt-PA or acetyl-streptokinase and to find out any correlation between the plasma t-PA, PAI-1 and DD levels with the infarct size as it is estimated from the peak of serum CPK levels. The plasma antigen levels of t-PA, PAI-1 and DD were measured by the enzyme immunoassay method (Stago), in 57 consecutive patients (M = 46, F = 11, mean age 55.6 +/- 8.8 years) and in 25 normal subjects (M = 18, F = 7, mean age 54.0 +/- 5.5 years). In 47 out of the 57 patients who were treated successfully with 100 mg of rt-PA (26 patients) or with 1.5 MU 21 of acetyl-streptokinase, as well as in 10 patients who were not treated, samples were obtained again 4 and 24 hours after the end of thrombolytic therapy or admission, respectively. During the acute phase of myocardial infarction the t-PA, PAI-1 and DD antigen plasma levels were significantly higher than in healthy people. There were no significant changes in the t-PA, PAI-1 and DD plasma levels of the patients who were not treated with a thrombolytic agent. We found a significant elevation of t-PA (p < 0.001), PAI-1 (p < 0.05) and DD (p < 0.001) after 4 hours in comparison with the baseline (at presentation, before therapy). After 24 hours the t-PA and DD plasma levels remained significantly higher (p < 0.001) while the PAI-1 plasma levels returned to the pre-therapy levels. There were no significantly different changes in the t-PA, PAI-1 and DD plasma levels of either group of patients, treated with rt-PA or acetyl-streptokinase while the t-PA and PAI-1 levels were positively correlated with infarct size as estimated from peak serum CPK levels.     

亚低温联合升压对大鼠局灶脑缺血再灌注后血脑屏障、脑组织水含量的影响

目的探讨升压联合亚低温治疗局灶性脑缺血再灌注损伤的可行性及效果。方法取64只大鼠制作局灶性脑缺血再灌注模型,随机分为对照组、升压组、亚低温组及升压联合亚低温治疗组(联合组)。对照组不予处理,后三组分别予升压治疗、亚低温治疗及升压加亚低温联合治疗;观察各组治疗后神经功能缺失评分、血脑屏障破坏情况和脑组织水含量。结果升压组、亚低温组及联合组神经功能缺失评分、Even's蓝染色体积均明显低于对照组(P分别<0.05、<0.01);联合组Even's蓝染色体积小于升压组和亚低温组(P均<0.05),升压组、亚低温组和联合组脑组织水含量均明显低于对照组(P均<0.05)。结论升压和亚低温能明显减轻局灶性脑缺血再灌注后大鼠血脑屏障破坏和脑水肿,联合应用作用更强。     

磷酸二酯酶5抑制剂促进大鼠脑缺血再灌注后神经及血管再生的研究

目的探讨磷酸二酯酶5抑制剂西地那非对大鼠脑缺血再灌注后海马神经前体细胞标记物微管相关蛋白增殖及血管内皮细胞生长因子(VEGF)表达的影响。方法雄性SD大鼠75只,随机分为假手术组5只,局灶性脑缺血再灌注组(单纯缺血组)35只及局灶性脑缺血+西地那非组(西地那非组)35只。西地那非组在大脑中动脉局灶缺血模型再灌注后2 h喂服西地那非3 d。单纯缺血组和西地那非组在术后2 h、1 d、3 d、5 d、7 d、10 d和14 d检测神经功能缺损评分。免疫组织化学方法检测各时间点海马神经前体细胞标记物微管相关蛋白阳性细胞及梗死灶周围VEGF的吸光度值。结果假手术组几乎无微管相关蛋白表达。与单纯缺血组比较,西地那非组7 d、10 d、14 d神经功能缺损评分明显升高,差异有统计学意义(P<0.05);西地那非组5 d、7 d、10 d、14 d微管相关蛋白明显高于单纯缺血组,差异有统计学意义(P<0.05,P<0.01);西地那非组3 d、5 d、7 d、10 d VEGF明显高于单纯缺血组,差异有统计学意义(P<0.05,P<0.01)。结论西地那非能够促进大鼠脑缺血再灌注后急性期神经及血管再生,改善神经功能。     

局部亚低温对大鼠局灶脑缺血再灌注后β淀粉样蛋白表达及梗死体积的影响

目的观察病变侧缺血至再灌注期亚低温（32～33℃）对大鼠局灶性脑缺血再灌注后梗死体积和β淀粉样蛋白（β—amyloid protein,Aβ）表达的影响。方法采用改良线栓法建立大鼠大脑中动脉缺血再灌注模型,随机分为假手术组、常温缺血组和亚低温缺血组,两个缺血组各分为5个亚组：分别于缺血后2、3、6、8、12h进行再灌注4h后处死,其中亚低温组于缺血后30min实施病灶侧脑部亚低温并持续至再灌注期。处死大鼠前进行神经功能缺陷评分,TTC染色及运用计算机图像分析技术观察各组大鼠脑梗死体积,采用免疫组织化学法检测Aβ表达,末端脱核苷酸转移酶介导的dUTP缺口末端标记技术（TUNEL）观察神经细胞凋亡情况。结果与常温缺血组比较,亚低温缺血组大鼠脑梗死体积明显减少,Aβ阳性细胞数量明显减少（P〈0．05）,凋亡的神经细胞明显减少（P〈0．05）。神经功能缺陷评分亚低温缺血组明显低于相应时间点常温缺血组（P〈0．05或P〈0．01）。结论病变侧亚低温对脑缺血有保护作用,其机制可能为亚低温抑制Aβ表达,进而抑制神经元凋亡,减少脑梗死体积,促进脑缺血后神经功能恢复。     

Fructose 1,6-diphosphate alleviates myocardial ischemia reperfusion injury in rats through JAK2/STAT3 pathway

Objective: To study the effect of fructose 1,6-diphosphate(FDP) on myocardial ischemia reperfusion injury in rats and its molecular mechanism.Methods: Male SPF SD rats were selected as experimental animals and randomly divided into four groups.Sham group received sham operation, I/R group were made into myocardial ischemia reperfusion injury models, FDP group were made into myocardial ischemia reperfusion injury models and then were given FDP intervention, and FDP+AG490 group were made into myocardial ischemia reperfusion injury models and then were given FDP and JAK2 inhibitor AG490 intervention.Results: CK, CK-MB, c Tn I and LDH contents in serum as well as Bax and Caspase-3 protein expression in myocardial tissue of I/R group were significantly higher than those of Sham group whereas Bcl-2, p-JAK2 and p-STAT3 protein expression in myocardial tissues were significantly lower than those of Sham group; CK, CK-MB, c Tn I and LDH contents in serum as well as Bax and Caspase-3 protein expression in myocardial tissue of FDP group were significantly lower than those of I/R group whereas Bcl-2, p-JAK2 and p-STAT3 protein expression in myocardial tissue were significantly higher than those of I/R group; CK, CK-MB, c Tn I and LDH contents in serum as well as Bax and Caspase-3 protein expression in myocardial tissue of FDP+AG490 group were significantly higher than those of FDP group whereas Bcl-2 protein expression in myocardial tissue was significantly lower than that of FDP group.Conclusion: FDP could reduce the myocardial ischemia reperfusion injury in rats by activating the JAK2/STAT3 pathway.     

厄贝沙坦对大鼠心肌缺血再灌注细胞凋亡与细胞外信号调节激酶通路的影响

目的观察厄贝沙坦对大鼠缺血再灌注心肌细胞凋亡的影响,并探讨其与细胞外信号调节激酶(ERK)通路的关系。方法健康雄性SD大鼠72只,随机分为假手术组、缺血再灌注组、缺血预处理组、厄贝沙坦组、厄贝沙坦+PD-98059组(PD组)。厄贝沙坦灌胃1周后制作大鼠心肌缺血再灌注模型,PD-98059于缺血前15 min尾静脉注射。实验结束后用TTC染色测定心肌梗死面积;免疫组织化学法检测心肌组织BcI-2、Bax表达;Western blot法测定磷酸化ERK的活性;TUNEL检测凋亡细胞指数。结果与假手术组比较,缺血再灌注组、缺血预处理组、厄贝沙坦组、PD组心肌细胞凋亡指数、磷酸化ERK活性及Bcl-2、Bax表达明显增加(P<0.01);与缺血再灌注组比较,缺血预处理组、厄贝沙坦组心肌梗死面积、心肌细胞凋亡指数和Bax表达明显降低,磷酸化ERK活性及Bcl-2表达明显增加(P<0.01);与厄贝沙坦组比较,缺血再灌注组、PD组心肌梗死面积、心肌细胞凋亡指数和Bax表达明显增加,磷酸化ERK活性及Bcl-2表达明显降低,差异有统计学意义(P<0.01)。结论厄贝沙坦能够激活ERK通路,进一步调控Bcl-2、Bax蛋白的表达,抑制再灌注心肌细胞的凋亡。     

Heparin enhances active site-dependent binding of tissue-type plasminogen activator to endothelial cells.

Human umbilical vein endothelial cells (HUVEC) in culture express two classes of binding sites for tissue-type plasminogen activator (t-PA). The high-affinity binding site has been identified as PA inhibitor type 1 (PAI-1), which binds to the catalytic portion of the molecule, while the second site binds t-PA through an active-site independent domain. Because recombinant t-PA (rt-PA) is often administered concomitantly with heparin, we investigated the effects of heparin on rt-PA binding to HUVEC. Preincubation of HUVEC with heparin at 4 degrees C increased the binding of radiolabeled rt-PA in a time- and dose-dependent manner. One-half maximal increase in binding was observed within 10 minutes of heparin addition. When HUVEC were preincubated with optimal concentrations (5 U/mL) of heparin for 4 hours at 4 degrees C, a 2.5- +/- 0.2-fold increase in specific binding was observed (mean +/- SEM, n = 12, P less than .01). Other highly sulfated glycosaminoglycans and fucoidan (a sulfated polymer of fucose) stimulated rt-PA binding as well, whereas glycosaminoglycans with lower sulfate content than heparin did not. Several results suggested that heparin increased the binding of rt-PA to "cell-associated" PAI-1. First, only active-site-dependent binding was enhanced by heparin, whereas binding of active-site blocked rt-PA was not affected. Second, extracts from HUVEC preincubated with heparin contained increased amounts of rt-PA-PAI-1 complexes as shown by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. Third, antibodies to PAI-1 blocked the increased binding entirely. HUVEC preincubated with heparin also bound increased amounts of enzymatically active radiolabeled urokinase-type PAs. However, HUVEC preincubated with heparin did not express increased amounts of immunoreactive PAI-1. Therefore, heparin, at therapeutic concentrations, may enhance or stabilize the association of PAs with endothelial cell-associated PAI-1.