吡格列酮对大鼠缺血再灌注诱导的内质网应激相关的心肌保护作用

目的观察吡格列酮对大鼠心肌缺血再灌注损伤（MIRI）时JNK、p-JNK及caspasc-12蛋白表达的影响,探讨吡格列酮通过JNK通路对内质网应激途径的心肌保护作用。方法Wistar大鼠40只随机分为假手术组（sham组）、缺血再灌注组（I／R组）、I／R＋Pio（吡格列酮）组及I／R＋Pi0＋sP600125组各10只。制作大鼠MIRI模型;TUNEL检测心肌细胞凋亡,免疫组织化学检测各组caspase-12表达变化,westernBlot法检测各组JNK、P-JNK的表达。结果吡格列酮预处理组大鼠心肌细胞凋亡、JNK磷酸化率及caspase-12蛋白表达水平明显比I／R组降低（P〈0．05）,加用JNK抑制剂（SP600125）后上述指标进一步下降,与吡格列酮组比较差异有统计学意义（P〈0．05）。结论缺血再灌注损伤可激活JNK通路,诱导过度的ERS,增加ER凋亡信号介导的细胞凋亡。吡格列酮预处理可减少ER凋亡信号介导的细胞凋亡,JNK信号途径在吡格列酮预处理抑制ER凋亡信号分子活化的机制中发挥重要作用。     

吡格列酮通过p-CREB蛋白对大鼠缺血再灌注损伤心肌保护机制的研究

目的通过检测大鼠心肌缺血再灌注p-CREB蛋白表达的变化,探讨吡格列酮对大鼠缺血再灌注损伤心肌保护机制。方法将55只SD大鼠随机分为假手术组、缺血再灌注组、吡格列酮组、吡格列酮+GW9662组,左前降支结扎的方法建立缺血再灌注损伤模型,伊文思蓝染色测定心肌梗死面积,Western blot法测定心肌组织p-CREB蛋白表达。结果吡格列酮组梗死面积与缺血再灌注组比较明显减少(P0.05),与吡格列酮组比较,吡格列酮+GW9662组梗死面积差异有统计学意义(P0.05)。与假手术组和缺血再灌注组相比,吡格列酮组p-CREB蛋白表达明显增加(P0.05),吡格列酮+GW9662组p-CREB蛋白表达无明显变化(P0.05);与吡格列酮组相比,吡格列酮+GW9662组p-CREB蛋白表达减少,差异有统计学意义(P0.05)。结论吡格列酮可能上调p-CREB蛋白表达进而抑制缺血再灌注诱导的心肌细胞损伤,GW9662可逆转吡格列酮对心肌细胞的保护作用。     

吡格列酮对缺血再灌注大鼠心肌细胞内质网应激致凋亡途径的影响

目的 观察吡格列酮对大鼠心肌细胞缺血再灌注(I/R)损伤(MIRI)后GRP78和caspase - 12蛋白表达的影响,探讨吡格列酮内质网应激途径的心肌保护.方法 Wistar大鼠30只随机分为I/R+ Pio组[灌服5 mg/(kg·d)]、I/R组及假手术组,各10只.制作大鼠心肌再灌注损伤模型.TUNEL检测心肌细胞凋亡,免疫组织化学检测GRP78和caspase - 12表达变化.结果 吡格列酮预处理组大鼠心肌细胞凋亡及GRP78、caspase - 12蛋白表达水平明显比I/R组减少(P＜0.05).结论 通过内质网应激途径可能是吡格列酮对心肌再灌注损伤的保护作用机制之一.     

吡格列酮对大鼠缺血再灌注心肌p38丝裂原活化蛋白激酶表达的影响

目的观察临床用于降糖治疗的噻唑烷二酮类药物吡格列酮对大鼠缺血再灌注损伤心肌的保护作用及对p38丝裂原活化蛋白激酶表达的影响。方法将24只健康雄性SD大鼠随机分为4组:假手术组(Sham组)、缺血再灌注组(I/R组)、吡格列酮10mg/(kg·d)组(P组)、吡格列酮10mg/(kg·d)+过氧化物酶体增殖物激活受体γ(PPARγ)特异性阻断剂GW9662组(P+G组),每组6只;利用结扎左前降支的方法建立缺血再灌注损伤模型,脱氧核糖核苷酸末端转移酶介导的缺口原位末端标记法检测心肌细胞凋亡,Western blot方法检测心肌组织磷酸化p38(p-p38)蛋白的变化。结果与I/R组比较,Sham组、P组心肌细胞凋亡指数(AI)显著降低[(8.6±4.3)%、(21.4±8.8)%vs(40.1±12.3)%,P0.05];P+G组心肌细胞AI显著高于P组[(37.0±10.5)%vs(21.4±8.8)%,P0.05]。与I/R组比较,Sham组、P组p-p38蛋白表达下调,差异有统计学意义(P0.05),与P组比较,P+G组p-p38蛋白表达上调,差异有统计学意义(P0.05)。结论吡格列酮抑制缺血再灌注损伤诱导的心肌细胞凋亡,可能与下调p-p38表达有关,这2种作用是由PPARγ介导的。     

吡格列酮保护大鼠心肌缺血再灌注损伤机制的研究

目的探讨吡格列酮保护大鼠心肌缺血再灌注损伤的机制,观察细胞外信号调节激酶1/2(ERK1/2)、低氧诱导因子-1α(HIF-1α)表达的变化。方法将SD大鼠30只随机分为5组:假手术组,缺血再灌注组,吡格列酮5mg组,吡格列酮10mg组和吡格列酮20mg组,每组6只,利用体内结扎左前降支的方法建立缺血再灌注损伤模型,Western blot法检测心肌组织ERK1/2、磷酸化ERK1/2的变化,RT-PCR法检测HIF-1α mRNA的变化。结果缺血再灌注组心肌组织ERK1/2表达较假手术组无变化,吡格列酮各组对其表达无影响;缺血再灌注组磷酸化ERK1/2表达上调,吡格列酮各组表达进一步上调,与吡格列酮剂量相关;缺血再灌注组HIF-1α mRNA表达上调,吡格列酮各组促进其进一步上调,与剂量无关。结论心肌缺血再灌注损伤时,机体可调动内源性生存激酶表达上调,应对急性损伤,吡格列酮可进一步促进这些激酶上调,发挥抗心肌缺血再灌注损伤作用。     

非诺贝特对大鼠心肌缺血再灌注损伤的保护作用及其机制研究

目的探讨非诺贝特对大鼠心肌缺血再灌注损伤的保护作用及其机制O方法将64只sD大鼠随机分为假手术组、缺血再灌注组、150mg／kg非诺贝特组及300mg／kg非诺贝特组,每组各16只,术前30min分别给予相应处理。采取体内结扎左前降支的方法建立心肌缺血再灌注损伤模型,予酶联免疫吸附法检测大鼠心肌组织中NF-xBp65及IL-6水平,H·E染色观察左一t7室前壁细胞病理形态学改变,并采用Tunel法检测心肌细胞凋亡率。结果假手术组大鼠一t7肌组织中NF-xBp65及IL-6水平、心肌细胞凋亡率分别为（8．11±0．83）pg／mg、（182．67±0．19）pg／mg、（5．09±0．79）％,与其余四组大鼠相比均显著降低（P〈0．05）;与缺血再灌注组比较,非诺贝特组大鼠心肌组织中NF-xBp65及IL-6水平,心肌细胞凋亡率明显降低（P〈0．05）,且随着用药剂量的增加而降低,两个不同剂量组比较,差异有统计学意义（P〈0．05）。缺血再灌注组与300mg／kg非诺贝特组中NF-xBp65及IL-6含量水平差异有统计学意义（rl=0．93,r2：0．74,P〈0．01）。结论非诺贝特可通过负性调节NF-xBp65含量水平进而减少IL-6的释放,抑制心肌细胞的凋亡,从而在心肌缺血再灌注损伤中发挥保护作用。     

牛磺酸对大鼠心肌缺血再灌注损伤细胞凋亡的影响

目的观察牛磺酸对大鼠心肌缺血再灌注损伤后细胞凋亡的影响。方法实验大鼠40只,随机分为5组：假手术组（8只）,再灌注模型组（8只）,牛磺酸低、中、高剂量（30mg／kg、100mg／kg、300mg／kg）组（各8只）。再灌注后观察各组血清SOD、LDH、MDA含量,TUNEL法检测心肌细胞凋亡。结果①牛磺酸对大鼠心肌缺血再灌注后血清SOD、LDH、MDA含量的影响：与假手术组比较,其余各组大鼠血清SOD活性明显降低,LDH、MDA含量明显增高（P〈0．05,P〈0．01）;与模型组比较,牛磺酸中、高剂量组大鼠血清SOD活性明显升高（P〈0．01）,LDH、MDA含量明显降低（P〈0．05,P〈0．01）。②牛磺酸对大鼠心肌缺血再灌注（I／R）损伤后细胞凋亡的影响：I／R后心肌细胞凋亡指数（AI）为（45．6±4．6）,明显高于假手术组的（8．50±1．13）（P〈0．01）,牛磺酸低、中、高组分别为（37．03±3．52）、（30．32±8．23）和（25．62±6．12）,均明显低于I／R（P〈0．01）。结论牛磺酸可降低再灌注损伤大鼠氧自由基值,抑制心肌细胞凋亡。     

匹格列酮对大鼠肝脏缺血再灌注损伤的保护作用

目的探讨过氧化物酶体增生物激活受体γ激动剂匹格列酮对大鼠肝脏缺血再灌注损伤的作用及作用机制。方法成年Wistar大鼠50只,制作肝脏缺血再灌注模型,随机分为两组。对照组缺血前1h腹膜内注射5％土温-80（10ml／kg）,实验组缺血前1h腹膜内注射匹格列酮（10mg／kg）。两组分别在缺血前、再灌注1、3、6、12h取血测丙氨酸转氨酶（ALT）、天冬氨酸转氨酶（AST）和乳酸脱氢酶（LDH）,取肝脏标本作组织病理学检查。结果实验组与对照组比较,再灌注1、3、6、12h的ALT浓度降低,差异有统计学意义（P均〈0．01）。肝脏组织形态学检查显示实验组较对照组肝脏细胞损伤明显减轻。结论匹格列酮可以减轻大鼠肝脏缺血再灌注后肝组织损伤,并有助于缺血再灌注损伤后肝功能的恢复。     

磺脲类药物对兔心肌缺血再灌注损伤后适应影响的研究

目的观察磺脲类药物对兔心肌缺血再灌注损伤后适应影响及其机制。方法将30只新西兰大白兔随机分为5组：（1）假手术组,仅穿线不作冠状动脉结扎;（2）缺血-再灌注组,缺血45分钟,再灌注2小时;（3）后适应组,缺血45分钟,然后行短暂灌注30秒,缺血30秒,共3次,再行全面的2小时再灌注;（4）格列美脲组,实验开始时外周静脉注射格列美脲0.2mg/kg ,其余操作同后适应组;（5）格列本脲组,实验开始时外周注射格列本脲0.5mg/kg ,其余操作同后适应组。实验结束时测各组血清肌钙蛋白含量及心肌梗死面积。结果肌钙蛋白含量假手术组明显低于各手术组,后适应组与格列美脲组显著低于缺血再灌注组与格列本脲组,差异均有统计学意义（ P＜0.01）,而后适应组与格列美脲组及缺血再灌注组与格列本脲组差异均无统计学意义（ P＞0.05）。心肌梗死面积后适应组、格列美脲组明显低于缺血再灌注组及格列本脲组,差异有统计学意义（ P＜0.01）;后适应组与格列美脲组、缺血再灌注组与格列本脲组之间差异无统计学意义（ P＞0.05）。结论格列本脲可消除后适应兔心肌缺血再灌注损伤的保护作用,而格列美脲却对后适应保护作用无影响。     

吡格列酮预处理对大鼠缺血再灌注心肌细胞凋亡和线粒体超微结构的影响

目的:观察PPARγ激动剂吡格列酮对在体大鼠心肌缺血/再灌注(I/R)心肌细胞凋亡和线粒体超微结构的影响以及其可能机制。方法:将42只SD大鼠随机分为假手术组(对照组)、I/R组、吡咯列酮预处理组(预处理组)。I/R组、预处理组于I/R前24 h分别由尾静脉注射相应溶媒(0.9%氯化钠溶液)及吡格列酮(3 mg/kg)。对照组不结扎前降支,4 h后取出心脏;余2组结扎前降支30 min,再灌注4 h后取出心脏。每组取8只,用透射电镜观察心肌线粒体的超微结构改变,采用TUNEL法和免疫组化法检测各组缺血心肌细胞凋亡和Bcl-2、Bax、caspase-3蛋白的表达,RT-PCR法测p38 MAPK和JNK的mRNA表达;Western blot法测核转录因子-κBp65(NFκB p65)蛋白水平的表达;每组取6只,行心肌梗死面积测定。结果:①与I/R组相比,预处理组线粒体损伤程度明显减轻,梗死面积明显减少;②与I/R组相比,预处理组能明显增加Bcl-2蛋白的阳性细胞指数(P<0.05),降低心肌细胞凋亡率(P<0.05)及Bax、caspase-3蛋白的阳性细胞指数(P<0.05);③与对照组相比,I/R组p38 MAPK和JNK的mRNA表达水平及NFκB p65蛋白表达水平明显增加(P<0.05);与I/R组相比,预处理组能抑制以上水平的过度表达(P<0.05)。结论:吡格列酮预处理可通过保护心肌线粒体结构,减少心肌细胞凋亡起到抗I/R损伤作用,该保护作用机制可能与下调p38 MAPK和JNK的mRNA表达及NFκB p65蛋白表达活性有关。     

Pioglitazone,a specific ligand of the peroxisome proliferator-activated receptor gamma reduces gastric mucosal injury induced by ischaemia/ reperfusion in rat

BACKGROUND: The peroxisome proliferator-activated receptor gamma (PPARgamma) is a ligand-dependent nuclear receptor that has been implicated in the control of metabolism and numerous cellular processes, including cell cycle control, carcinogenesis, and inflammation. The present study was designed to investigate the effect of the specific PPARgamma ligand, pioglitazone, on the mucosal lesions induced by ischaemia and reperfusion (I/R) in rats. METHODS: I/R lesions were induced in Wistar rats by applying a small clamp to the coeliac artery for 30 min (ischaemic phase), followed by the removal of the clamp for 3 h (reperfusion phase). Vehicle (saline) or increasing doses of pioglitazone (2.5, 10, and 30 mg/kg i.g.) were given 30 min before exposure to I/R. The animals were killed immediately after the end of the reperfusion phase (time 0) and at 12 and 24h after I/R. The area of gastric lesions was measured by planimetry, and the gastric blood flow was determined by the H2 gas clearance method. The gastric mucosal gene expressions of PPARgamma, interleukin-1beta (IL-1beta), tumour necrosis factor alpha (TNF-alpha), leptin, cyclooxygenase-1 (COX-1) and cyclooxygenase-2 (COX-2) were examined by RT-PCR. In addition, protein expression of COX-2 and leptin was assessed by Western blot. RESULTS: The pretreatment with pioglitazone reduced in a dose-dependent manner the mean lesion area induced by I/R, and this effect was accompanied by a significant increase in the gastric blood flow. The decrease in gastric ulcerations by pioglitazone was also observed 12 and 24 h after the I/R. The PPARgamma mRNA was weakly expressed in the intact gastric mucosa but significantly up-regulated after exposure to I/R at each time interval studied. The expression of IL-1beta was not changed significantly after pioglitazone applied i.g. at doses 2.5 and 10 mg/kg, but it was down-regulated at the dose 30mg/kg. TNFalpha mRNA was strongly increased after the exposure to I/R, but it was down-regulated after pioglitazone pretreatment. In contrast, both leptin and COX-2 mRNA and protein expression were increased in the gastric mucosa after exposure to I/R. The pretreatment with pioglitazone caused a significant up-regulation of mRNA and protein expression of leptin, reaching its peak at the dose 30 mg/kg i.g. In contrast, COX-2 expression did not change significantly after the 2.5 and 10 mg/kg of pioglitazone, but it significantly decreased after pioglitazone at dose 30 mg/kg given to rats before exposure to I/R. CONCLUSIONS: Pioglitazone reduces the acute erosions and deeper gastric lesions induced by I/R. The beneficial effect of this PPARgamma ligand on I/R-induced gastric damage may be due to its anti-inflammatory properties, especially to the reduction in TNF-alpha expression and to up-regulation of leptin mRNA in the gastric mucosa. The inhibition of COX-2 expression by pioglitazone may reflect the anti-inflammatory properties of this compound.     

蛋白酶激活受体-2对缺血再灌注大鼠心肌细胞凋亡的影响

目的 探讨蛋白酶激活受体2(PAR-2)对缺血再灌注大鼠心肌细胞凋亡的影响.方法 40只雄性SD大鼠随机分为5组:假手术组(sham组),缺血再灌注组(I/R组)和丝-亮-异亮-甘-精-亮-酰胺(SLIGRL-NH2)低剂量组(0.5 mg/kg)、中剂量组(1 mg/kg)、高剂茸组(3 mg/kg),每组8只,建立大鼠在体心肌缺血再灌注模型.采用末端标记法(TUNEL)和DNA琼脂糖凝胶电泳的方法检测心肌细胞凋亡,免疫组织化学法检测凋亡相关蛋白Bcl-2、Bax的表达,实时荧光定量PCR检测心肌细胞PAR-2mRNA的表达情况.结果 (1)SLIGRL-NH2中、高剂量组凋亡指数明显低于I/R组(SLIGRL-NH2中、高剂量组分别为23.36%±3.77%、15.56%±1.24%比I/R组35.19%±4.50%,P<0.05～0.01);凋亡相关蛋白Bcl-2高于I/R组(SLIGRL-NH2中、高剂量组分别为0.983±0.103、1.197±0.119比I/R组0.761±0.043,P<0.05～0.01);凋亡相关蛋白Bax的表达显著低于I/R组(SLIGRL-NH2中、高剂量组分别为0.646±0.041,0.578±0.029比I/R组0.759±0.035,P均<0.01);PAR-2mRNA的表达明显高于I/R组(SLIGRL-NH2中、高剂量组分别为3.73±0.45,7.62±0.81比I/R组1.42±0.41,P均<0.01).(2)DNA凝胶电泳结果显示,I/R组、SLIGRL-NH2低剂量组可见到DNA梯带,假手术组和SLIGRL-NH2中、高剂量组则无明显DNA梯带.结论 PAR-2激动剂SLIGRL-NH2可上调并激活PAR-2,并通过增加Bcl-2/Bax的比值抑制大鼠缺血再灌注心肌细胞的凋亡而发挥心肌保护效应,且该作用具有一定的剂量依赖效应.     

缺血后处理对高血脂大鼠缺血/再灌注心肌Caspase-3活性的影响

目的：观察缺血后处理对高血脂大鼠缺血再灌注心肌Caspase（半胱氨酸天冬氨酸酶）-3活性的影响。方法：选择高血脂SD大鼠48只,随机分为3组：假手术组（开胸后穿线做套环,但不收紧结扎线）、缺血再灌注组（收紧结扎线缺血40min,放松结扎线再灌注240min）、缺血后处理组（缺血40min后,再灌注10s,缺血10s,连续3个循环,然后再灌注240min）,每组16只。再灌注结束后自右颈动脉采血,测定血清肌酸激酶（CK）活性,再灌注心肌凋亡程度,及Caspase-3活性,并进行比较分析。结果：再灌注结束后,①缺血后处理组和缺血再灌注组CK活性明显高于假手术组[（745.26±62.18）U/L比（926.38±76.49）U/L比（237.67±21.82）U/L],缺血后处理组明显低于缺血再灌注组（P均〈0.05）;②心肌凋亡细胞计数：假手术组未见明显细胞凋亡（〈5%）,缺血后处理组心肌细胞凋亡率明显低于缺血再灌注组[（11.7±2.6）%比（20.8±3.4）%,P〈0.05];③缺血后处理组缺血区心肌组织Caspase-3活性明显低于缺血再灌注组[（545.79±98.25）μmol PNA/mg比（739.83±113.57）μmol PNA/mg,P〈0.01]。结论：缺血后处理可以减轻高血脂大鼠缺血再灌注损伤,其心肌保护作用可能与降低Caspase-3活性有关。     

促红细胞生成素衍生肽抑制缺血/再灌注损伤诱导的大鼠心肌细胞凋亡

目的:探讨促红细胞生成素(erythropoietin,EPO)衍生肽又称螺旋B表面肽(helix B surface peptide,HBSP)在大鼠心肌缺血/再灌注损伤(I/RI)中的拮抗作用及其机制。方法:82只200~250 g雄性SD大鼠随机分为假手术(Sham)组(n=18)、缺血/再灌注(I/R)组(n=18)、EPO组(n=18)、HBSP组(n=18)及HBSP+LY294002(PI3k特异性抑制剂)组(n=10)。于灌注前5 min,于EPO组及HBSP组大鼠的尾静脉分别注射生理盐水重组人EPO(rhEPO;3 000 U/kg,4 ml/kg)及生理盐水HBSP(60μg/kg,4 ml/kg)。颈动脉插管检测血流动力学指标,采用小动物超声分别检测24 h、1周后大鼠心功能。用TTC-EB双染测定梗死面积,Western blot法检测心肌组织蛋白激酶B(Akt)和磷酸化Akt的表达。用TUNEL法检测心肌细胞凋亡。结果:与I/R组相比,EPO组和HBSP组再灌注后大鼠心脏左室收缩压(LVSP)、左室内压最大上升速率(+dp/dtmax)以及最大下降速率(-dp/dtmax)明显改善(P<0.05),左室射血分数[LVEF(%)]、室间隔厚度(IVSS)及左室短轴缩短率[FS(%)]显著增加(P<0.05),同时心肌梗死面积明显缩小(P<0.05),心肌细胞凋亡显著减少(P<0.05);HBSP组Akt磷酸化水平显著提高(P<0.05)。HBSP+LY294002组与HBSP组相比,Akt磷酸化水平明显降低,心肌细胞凋亡指数显著增高(P<0.05)。HBSP组与EPO组间各项指标均无显著差别。结论:HBSP能够显著抑制I/RI诱导的大鼠心肌细胞凋亡,减少梗死面积,明显改善心功能,其保护作用可能与激活PI3K-Akt通路有关。     

Cardioprotective Effects of Angiotensin II Type 1 Receptor Blockade with Olmesartan on Reperfusion Injury in a Rat Myocardial Ischemia‐Reperfusion Model

We determined the effects of olmesartan on infarct size and cardiac function in a rat ischemia/reperfusion model. Rats underwent 30 min of left coronary artery (CA) occlusion followed by 2 h of reperfusion. In protocol 1, the rats received (by i.v.) 1 mL of vehicle at 10 min after CA occlusion (Group 1, n = 15); olmesartan (0.3 mg/kg) at 10 min after CA occlusion (Group 2, n = 15); 1 mL of vehicle at 5 min before CA reperfusion (Group 3, n = 15); or olmesartan (0.3 mg/kg) 5 min before CA reperfusion (Group 4, n = 15). In protocol 2, the rats received (by i.v.) 1 mL of vehicle at 5 min before CA reperfusion (Group 5, n = 21); or olmesartan (3 mg/kg) at 5 min before CA reperfusion (Group 6, n = 21). Systemic hemodynamics, left ventricular (LV) function, LV ischemic risk zone, no‐reflow zone, and infarct size were determined. In protocol 1, olmesartan (0.3 mg/kg) did not affect blood pressure (BP), heart rate, LV ± dp/dt or LV fractional shortening during the experimental procedure, and did not alter no‐reflow or infarct size. In protocol 2, olmesartan (3 mg/kg) significantly reduced infarct size to 21.7 ± 4.1% from 34.3 ± 4.1% of risk zone in the vehicle group (P= 0.035), but did not alter the no‐reflow size. Prior to CA reperfusion, olmesartan (3 mg/kg) significantly reduced mean BP by 22% and LV ±dp/dt, but did not affect heart rate. At 2 h after reperfusion, olmesartan significantly decreased heart rate by 21%, mean BP by 14%, and significantly increased LV fractional shortening from 54.1 ± 1.4% to 61.3 ± 1.6% (P= 0.0018). Olmesartan significantly reduced myocardial infarct size and improved LV contractility at a dose (3 mg/kg) with systemic vasodilating effects but not at a lower dose (0.3 mg/kg) without hemodynamic effects.     

心肌细胞凋亡在老年性心衰发生中的作用

目的探讨心肌细胞凋亡在老年心衰发生中的作用。方法制备大鼠心肌缺血／再灌注（MI／R）模型。雄性SD大鼠被分为4个实验组：青年假手术组（2个月,16只）、老年假手术组（24个月,16只）、青年手术组（2个月,16只）和老年手术组（24个月,16只）。心肌缺血／再灌注组大鼠的左冠状动脉近中段被阻断30rain后恢复血流再灌注3h和24h。通过MillarMikro—Tip导管压力换能器对大鼠左心室（LV）功能指标进行检测,从而对sD大鼠心脏功能进行评价。采用原位末端标记检测（TUNEL）法和Caspase-3活性检测评价心肌细胞凋亡水平,同时测定大鼠血浆中凋亡标志物sFas、TNF—α和IL-6水平。对大鼠心肌组织使用伊文氏蓝-TTC染色并测定血浆cTnI水平以确定心肌坏死程度。结果与青年大鼠相比,老年大鼠在心肌缺血／再灌注后心功能明显降低,同’时心肌细胞凋亡水平及心肌细胞坏死程度显著增加。血浆凋亡标志物的检测结果也表现出相同的趋势。结论年龄导致了缺血／再灌注后心功能的显著降低,心肌细胞凋亡水平的增加可能是引发上述现象的主要原因。     

有氧运动训练对大鼠心肌缺血/再灌注损伤致心肌细胞凋亡的作用

目的 应用大鼠在体心脏缺血/再灌注损伤（ischemia/reperfusion injury,I/RI）动物模型,观察缺血/再灌注(I/R)后运动训练（exercise training）对心肌细胞凋亡的作用以及与磷脂酸肌醇3激酶蛋白激酶B（PI3K/Akt）信号通路可能存在的相互作用,探讨运动训练对心脏保护作用的可能机制。方法 60只SD大鼠建模后随机分成3组:假手术组,I/R组,I/RI+运动训练组。LTTC染色检测心肌梗死范围;采用TUNEL荧光标记法检测心肌凋亡;Caspase-3试剂盒检测caspase-3活性;免疫印迹法检测p-Akt水平。结果 与I/R组比较,运动训练可以减少心肌梗死范围（n=9,P<0.01）,可以明显抑制心肌细胞凋亡（n＝10,P<0.01）,降低caspase-3活性（n=8,P<0.01）,有效提高I/R后心肌p-Akt水平（n=7,P<0.01）。结论 运动训练对I/RI的心肌具有保护作用,其可能是通过PI3K/Akt信号通路实现的。     

Cardioprotection mediated by rosiglitazone, a peroxisome proliferatoractivated receptor gamma ligand, in relation to nitric oxide

Activation of peroxisome proliferator-activated receptor (PPAR) gamma protects from myocardial ischemia/reperfusion injury. The aim of the study was to investigate whether the cardioprotective effect of PPARgamma is related to nitric oxide (NO). Methods Wild type (WT) and endothelial NO synthase (eNOS) knockout (KO) mice received 3 mg/kg of the PPARgamma agonist rosiglitazone or vehicle (n = 6–9 in each group) i. p. 45 min before anesthesia. The hearts were isolated, perfused in a Langendorff mode and subjected to global ischemia and 30 min reperfusion. The hearts of another two groups ofWT mice received the NOS inhibitor L-NNA (100 ìmol/l) or vehicle in addition to pre-treatment with vehicle or rosiglitazone. Results In the WT heart, rosiglitazone increased the recovery of left ventricular function and coronary flow following ischemia in comparison with the vehicle group.L-NNA did not affect recovery per se but significantly blunted the improvement in the recovery of left ventricular function induced by rosiglitazone. In the KO group rosiglitazone suppressed the recovery of myocardial function following ischemia. Expression of eNOS was not affected, but phosphorylated eNOS was significantly increased by rosiglitazone in the WT hearts (P < 0.05). Conclusion These results suggest that the cardioprotective effect of the PPARgamma agonist rosiglitazone is mediated via NO by phosphorylation of eNOS.