参附注射液对糖尿病大鼠心肌缺血／再灌注期间磷脂酰肌醇3激酶表达的影响

目的 探讨参附注射液(SFI)对糖尿病大鼠心肌缺血/再灌注(I/R)损伤的保护作用及其分子机制.方法 采用腹腔注射链脲佐菌素(STZ)法建立糖尿病大鼠模型.取制模成功的SD大鼠30只,喂养8周后随机分成假手术(sham)组、I/R组、SFI组,每组10只.sham组大鼠对冠状动脉(冠脉)只穿线不结扎;其余两组大鼠通过结扎心脏左冠脉前降支30 min、再灌注120 min制备I/R模型.SFI组于开胸前持续泵注SFI 10 ml·kg-1·h-1,开胸后为3 ml·kg-1·h-1;其余两组泵注等量晶胶液.光镜下进行心肌组织病理学观察,测定各组心肌梗死面积;原位末端缺刻标记法(TUNEL)检测心肌细胞凋亡,计算细胞凋亡指数;免疫组化染色检测心肌磷脂酰肌醇3激酶(PI-3K)表达.结果 SFI组心肌梗死面积较I/R组明显减少[(36.32±2.72)%比(47.26±3.48)%,P<0.05].I/R组凋亡细胞显著增多;SFI组凋亡细胞较I/R组显著减少,而多于sham组(P均<0.05).与sham组和I/R组比较,SFI组的心肌PI-3K表达明显升高(P均<0.05).结论 SFI能明显减轻糖尿病时心肌I/R损伤,其机制可能与激活PI-3K/Akt信号通路而发挥心肌保护作用有关.     

乙酰半胱氨酸对糖尿病大鼠心肌缺血/再灌注后低氧诱导因子-1α和血红素加氧酶-1基因表达的影响

目的:观察乙酰半胱氨酸(NAC)对糖尿病大鼠心肌缺血/再灌注(I/R)后低氧诱导因子-1α(HIF-1α)和血红素加氧酶-1(HO-1)mRNA表达变化的影响.方法:用链脲佐菌素(STZ)复制糖尿病大鼠模型,动物分为正常假手术组(Cs组)、正常I/R组(CI/R组)、正常I/R+NAC组(CN组)、糖尿病假手术组(Ds组)、糖尿病I/R组(DI/R组)、糖尿病I/R+NAC组(DN组),每组12只,共72只.检测各组心肌梗死范围(IS/AAR)、HI-1α和HO-1 mRNA表达.结果:Cs组检测不到HIF-1α和HO-1 mRNA表达,Ds组检测到少量HIF-1α和HO-1 mRNA表达;DI/R组HIF-1α和HO-1 mRNA表达低于CI/R组(P＜0.05),IS/AAR大于CI/R组(P＜0.05);DN组HIF-1α和HO-1 mRNA表达高于DI/R组,但低于CN组(P＜0.05);IS/AAR小于DI/RR组,但大于CN组(P＜0.05).结论:NAC可部分恢复糖尿病大鼠心肌I/R后HIF-1α和HO-1 mRNA表达,减小心梗面积,有一定的治疗效果.     

急性脑血管病患者血浆一氧化氮、垂体加压素、泌乳素的变化

目的探讨不同时期、病情、梗死面积和出血量的急性脑血管病患者(ACVD)血浆中一氧化氮(NO)、垂体加压素(AVP)、泌乳素(PRL)的变化及临床意义。方法脑梗死(C I)、脑出血(CH)患者,分别按意识障碍和肌力状况分为轻、重组。C I按梗死面积分为大梗死组、多发梗死组及单发性小梗死组;CH按出血量多少分为小于20 m l组;20~40 m l组;大于40 m l组;据不同病程分为急性期(发病后1小时至3天),恢复期(住院3周后)。对照组:30例同期健康体检者,测定对照组及患者入院时和3周后血浆中NO、AVP、PRL的水平。结果C I、CH患者NO、PRL、AVP均高于正常人,且病情越急,病情越重,脑梗死面积和出血量程度越大者,升高越明显,升高程度与患者愈后密切相关。至恢复期C I、CH患者NO、PRL、AVP已恢复正常。结论急性脑血管疾病患者急性期AVP、NO、PRL升高,可作为判断ACVD的严重程度和愈后的参考指标。     

心肌远隔缺血预适应通过SDF-1α/CXCR4途径保护兔心肌缺血/再灌注损伤的研究

目的:探讨远隔缺血预适应对心肌缺血/再灌注(I/R)损伤保护作用及潜在机制。方法:成年雄性新西兰大白兔随机分成:(1)心肌缺血再灌注组(I/R组,n=6);(2)假手术组(Sham,n=6);(3)远隔缺血预适应(RIPC+I/R组,n=6);(4)SDF-1α/CXCR4阻断剂AMD3100+I/R组,(n=6);(5)AMD3100+RIPC+I/R组,(n=6)。ELISA检测外周血中SDF-1α;TTC检测心肌梗死面积;TUNEL检测细胞凋亡率;Western Blot检测Bcl-2、Bax蛋白表达。结果:与Sham组相比,I/R组及RIPC+I/R组都可促进外周血中SDF-1α的释放,且后者的作用更显著(P0.05);RIPC+I/R及AMD3100+RIPC+I/R组可以不同程度缩小心肌梗死面积及降低心肌细胞凋亡率(P0.05),AMD3100+RIPC+I/R组与RIPC+I/R组相比,心肌梗死面积及细胞凋亡率均有所增加(P0.05)。结论:远隔缺血预适应可能通过SDF-1α/CXCR4信号通路对心缺血再灌注损伤心肌发挥保护作用。     

左旋精氨酸对急性心肌缺血/再灌注损伤大鼠内皮素-1的影响

目的 探讨内皮素-1(ET-1)在大鼠心肌缺血/再灌注(I/R)损伤过程中的变化规律及左旋精氨酸(L-Arg)的影响.方法 采用结扎冠状动脉前降支0.5h复制Wistar大鼠心肌I/R损伤模型.110只大鼠按随机数字表法分为假手术组(C)、缺血0.5h组(I)、缺血0.5h+再灌注0.5h组(R0.5)、缺血0.5h+再灌注1h组(R1)、缺血0.5h+再灌注2h组(R2)、L-Arg+假手术组(L+C)、L-Arg+缺血0.5h组(L+I)、L-Arg+缺血0.5h+再灌注0.5h组(L+R0.5)、L-Arg+缺血0.5h+再灌注1h组(L+R1)、L-Arg+缺血0.5h+再灌注2h组(L+R2).用酶联免疫吸附法测定各组大鼠血清肌酸激酶(CK)、乳酸脱氢酶(LDH)活性;用放射免疫法测量血清ET-1水平;用逆转录-聚合酶链反应(RT-PCR)、蛋白质免疫印迹法(Western blotting)检测各组心肌组织中ET-1 mRNA和蛋白表达.结果 Ⅰ组和R组血清CK、LDH、ET-1均较C组明显升高,且R组较Ⅰ组升高明显.R组ET-1 mRNA和蛋白表达均较C组明显升高,以R2组最为显著(ET-1mRNA:0.775±0.029比0.310±0.076;ET-1蛋白:0.773±0.055比0.340±0.099,均P＜0.05);而静脉给予L-Arg预处理可明显降低ET-1 mRNA和蛋白表达(ET-1 mRNA:0.340±0.049比0.775±0.029;ET-1蛋白:0.390±0.094比0.773±0.055,均P＜0.05).结论 在心肌I/R损伤的某些阶段可试用L-Arg进行干预,降低ET-1的表达.     

三羟基异黄酮对兔缺血心肌的保护作用

目的 探讨三羟基异黄酮(GST)对缺血/再灌注(I/R)心肌的保护效果及可能机制.方法 结扎雄兔冠脉左前降支建立心肌I/R模型:心肌缺血40min,然后再灌注2 h.分4组:Sham组:冠脉不结扎;I/R组;GST+I/R组:心肌缺血前5 min静脉注入1.0 mg/kg GST;Vehicle+I/R组:心肌缺血前5 min静脉注入1 mL二甲基亚砜.检测血清乳酸脱氢酶及肌酸激酶活性,再灌注结束后通过Evans蓝-TTC染色判断心肌梗死范围,TUNEL法检测心肌细胞凋亡.结果 与I/R组及Vehide+I/R组相比,GST+I/R组心肌梗死范围、心肌酶活性及细胞凋亡指数均显著降低(P<0.01),而前两组之间无显著差异.结论 心肌缺血前给予GST能有效地减轻心肌I/R损伤,抗凋亡和减少心肌细胞坏死是其发挥效应的两条途径.     

地塞米松诱导金属硫蛋白表达对大鼠缺血/再灌注损伤心肌的保护作用研究

目的 探讨地塞米松诱导金属硫蛋白(MT)表达对大鼠缺血/再灌注(I/R)损伤心肌的延迟保护作用.方法 将32只SD大鼠随机分成地塞米松组和对照组,分别予腹腔注射地塞米松和蒸馏水预处理.预处理24 h后构建Langendorff离体心脏I/R动物模型,缺血30 min后再灌注60 min.用蛋白质免疫印迹法(Western blotting)检测MT表达;动态观测缺血前及再灌注期间血流动力学指标[左心室发展压(LVDP)、左室内压上升和下降最大速率(±dp/dt max)、冠状动脉循环流出量(CF)]、心律失常的变化;测定心肌梗死面积、冠状动脉流出液肌酸激酶同工酶(CK-MB)漏出率、心肌丙二醛(MDA)、总超氧化物歧化酶(T-SOD)、铜锌-SOD(CuZn-SOD)、过氧化氢酶(CAT)、谷胱甘肽过氧化酶(GSH-Px)水平及心肌细胞膜Na+-K+-ATP酶、Ca2+-Mg2+-ATP酶活性.结果 与对照组比较,地塞米松组MT的表达水平显著增加(3.085±1.065比1.028±0.016,P＜0.05);再灌注期间LVDP、±dp/dt max及CF均得到明显改善(P均＜0.05);再灌注性室性心律失常评分明显减少[(2.00±1.41)分比(6.63±4.24)分,P＜0.05];心肌梗死面积明显缩小[(28.38±11.22)%比(47.39±8.30)%,P＜0.01];冠状动脉流出液CK-MB的漏出率明显降低[(8.69±4.16)U/g比(18.15±5.59)U/g,P＜0.01];心肌组织MDA含量降低(P＜0.05),T-SOD、CuZn-SOD、CAT、GSH-Px均明显升高(P＜0.05或P＜0.01);心肌细胞膜的Na+-K+-ATP酶、Ca2+-Mg2+-ATP酶活性增加(P＜0.01和P＜0.05).结论 地塞米松可能通过上调MT的表达,对大鼠I/R损伤心肌起到延迟保护作用.     

转录因子NF-E2相关因子在间歇性低氧大鼠心肌缺血/再灌注损伤中的保护机制

目的研究转录因子NF-E2相关因子(Nrf2)在间歇性低氧(IH)对大鼠心肌缺血再灌注(I/R)损伤的影响。方法制作成年SD大鼠心肌I/R模型,48只大鼠分为随机3组:假手术组(n=16)、I/R组(n=16)、IH+I/R组(n=16)。假手术组将生理盐水注进尾静脉,低氧处理(先给予2 min 6%~8%低氧,再进行3 min氧和处理,每次循环5次)制作IH动物模型,垫扎球囊法制作心肌I/R动物模型。术后检测心肌丙二醛(MDA)、谷胱甘肽(GSH)、肌酸激酶同工酶(CK-MB)含量。术后48 h处死,通过Western blot法检测Nrf2蛋白表达。结果 I/R组及IH+I/R组的心肌细胞MDA含量分别为16.82±6.26 nmol/L、7.53±4.18 nmol/L,GSH含量分别为132.17±3.54 mg/L、172.15±5.63 mg/L,CK-MB含量分别为2 601±3.75 U/L、1 538±2.87 U/L。I/R组及IH+I/R组Nrf2蛋白表达分别为0.217±1.326、0.872±4.538(P0.05)。与假手术组比较,I/R组CK-MB、MDA升高,GSH含量、Nrf2蛋白表达降低,差异均具有统计学意义(P0.05);与I/R组比较,IH+I/R组MDA、CK-MB含量降低,GSH含量、Nfr2蛋白表达升高,差异均具有统计学意义(P0.05)。结论间歇性低氧在大鼠心肌缺血损伤中具有心脏保护作用,其保护机制与Nrf2表达升高有关。     

参附注射液对糖尿病大鼠心肌缺血／再灌注损期间PTEN表达的影响

目的 观察参附注射液(SFI)对心肌缺血/再灌注期间糖尿病大鼠PTEN表达的影响,探讨其对糖尿病心肌缺血/再灌注损伤保护作用分子机制.方法 健康雄性SD大鼠,腹腔注射链尿佐菌素60 mg/kg制备糖尿病模型.造模成功的30只大鼠再喂养8周,随机分为三组(n=10):假手术组(S组)、缺血/再灌注组(I/R组)、SFI防治组(SFI组).S组只穿线包绕冠状动脉左前降支,I/R组结扎冠状动脉左前降支30 min后松开制备心肌缺血/再灌注模型,SFI组开胸前持续泵注SFI 10 mL·kg-1·h-1,开胸后以3 mL·kg-1·h-1持续输注至手术结束,S组和I/R组开胸前持续泵注晶胶液(晶胶比为3∶ 1)10 mL·kg-1·h-1,开胸后以3 mL·kg-1·h-1持续输注至手术结束.再灌注120 min时处死大鼠计算左心室心肌梗死面积、检测心肌凋亡百分比和PTEN表达,并观察心肌组织病理变化.结果 与S组比较,I/R组、SFI组心肌梗死面积,心肌细胞凋亡百分比均增加,PTEN表达增强(P＜0.05或0.01);与I/R组比较,SFI组心肌梗死面积,心肌细胞凋亡百分比和PTEN表达均降低(P＜0.05或0.01).SFI组心肌组织病理损伤程度明显轻于I/R组.结论 SFI能减轻糖尿病心肌缺血/再灌注损伤,其机制与其抑制心肌细胞PTEN的表达、减少心肌细胞凋亡有关.     

栀子苷预处理对大鼠心肌缺血再灌注后PI3K/Akt信号通路的研究

目的探索栀子苷(GEN)对大鼠心肌缺血再灌注(I/R)后心肌细胞氧化应激水平及心肌凋亡的影响极其与PI3K/Akt信号通路的关系。方法60只SD大鼠随机分为3组:缺血再灌注组(I/R),栀子苷预处理+缺血再灌注组(GEN+I/R),栀子苷+缺血再灌注组+PI3K/Akt信号通路抑制剂(LY294002)组(GEN+I/R+LY),GEN+I/R组在I/R造模前给予50 mg/kg GEN预处理,GEN+I/R+LY组在GEN预处理前给予0.3 mg/kg LY294002。ELISA法检测大鼠血清乳酸脱氢酶(LDH)、心肌组织丙二醛(MDA)和超氧化物歧化酶(SOD)以及钙泵(Ca~(2+)-ATPase)水平;Western blot检测心肌组织p-e NOS,p-Akt,Akt以及Bcl-2、Bax蛋白表达;免疫组织化学染色检测p-e NOS,p-Akt蛋白表达。结果与I/R组比较,GEN+I/R组LDH、MDA含量显著降低,SOD、Ca~(2+)-ATPase显著升高(P0.05);与GEN+I/R组比较,GEN+I/R+LY组LDH、MDA含量显著升高,SOD、Ca~(2+)-ATPase显著降低(P0.05)。并且,与I/R组比较,GEN+I/R组p-eNOS、p-Akt、Akt、Bcl-2表达量以及p-e NOS,p-Akt免疫荧光强度显著提高(P0.05),Bax蛋白表达显著降低(P0.05);与GEN+I/R组比较,GEN+I/R+LY组p-eNOS、p-Akt、Akt、Bcl-2表达量以及pe NOS、p-Akt免疫荧光强度显著降低,Bax蛋白表达量显著升高(P0.05)。结论栀子苷可通过激活PI3K/Akt信号通路抑制心肌缺血再灌注后氧化应激及细胞凋亡从而发挥保护作用。     

Gender differences in cardioprotection against ischemia/reperfusion injury in adult rat hearts: focus on Akt and protein kinase C signaling

Previous studies have reported the sex differences in heart susceptibility to ischemia/reperfusion (I/R) injury, but the mechanisms are not understood. The present study tested the hypothesis that Akt and protein kinase C (PKC)epsilon play an important role in the sexual dimorphism of heart susceptibility to I/R injury. Isolated hearts from 2-month-old male and female rats were subjected to I/R in the Langendorff preparation. The postischemic recovery of left ventricular function was significantly better, and infarct size was significantly smaller in female (37.1 +/- 1.9%) than in male (48.3 +/- 2.3%) hearts after 25-min ischemia followed by 2-h reperfusion. Inhibition of phosphatidylinositol 3-kinase/Akt pathway by wortmannin or PKC by chelerythrine chloride before ischemia significantly reduced postischemic recovery and increased infarct size in female but not male hearts. There were no differences in myocardial protein levels of heat shock protein 70, Akt, and PKCepsilon, respectively, between male and female rats. However, the ratio of phosphorylated (p)-Akt/Akt (0.58 +/- 0.05 versus 0.22 +/- 0.04; P < 0.05) and p-PKCepsilon/PKCepsilon (0.35 +/- 0.03 versus 0.22 +/- 0.02; P < 0.05) was significantly higher in female than in male hearts. In addition, there were significant increases in p-Akt and p-PKCepsilon levels during reperfusion in female but not in male hearts. The results suggest that increased p-Akt and p-PKCepsilon levels in female hearts contribute to the gender-related differences in heart susceptibility to I/R and play an important role in cardioprotection against I/R injury in females.     

钙拮抗剂硝苯吡啶对大鼠心肌缺血再灌注损伤的作用

目的研究钙拮抗剂(Calcium antagonists)硝苯吡啶(Nifedipine)对离体大鼠心肌缺血再灌注损伤的作用。方法 30只体重在260-300g的Wistar雄性大鼠随机分为三组:对照组、模型组、Nifedipine组(1μmmol/L)。大鼠麻醉后取出心脏,悬挂于Langendorff灌流装置上行主动脉逆行灌流,制备大鼠离体心脏缺血30min、再灌注120min模型;对照组行150min正常灌流。测定心肌梗死面积,检测SOD(Superoxidedismutas超氧化物歧化酶)及MDA(mal-onaldehyde丙二醛)的含量,免疫组化方法行PKCδ(The protein kinase C蛋白激酶C)的测定,用RT-PCR法测定NCX(Na+/Ca2+exchanger钠钙交换体)及SERCA2α(Sareoplasmie reticulum calcium adenodine triphosphatase肌浆网钙泵)的表达。结果硝苯吡啶组心肌梗死面积较模型组明显缩小(P<0.01);冠脉灌流液中SOD活性明显升高(P<0.01);MDA含量显著下降(P<0.01);药物组的PKC含量水平较模型组增多(P<0.05),药物组NCX mRNA的表达水平较模型组降低,存在显著差异(P<0.05)。结论钙拮抗剂Nifedipine对大鼠心肌缺血再灌注损伤有保护作用。     

Cardioprotection by sulfaphenazole, a cytochrome p450 inhibitor: mitigation of ischemia-reperfusion injury by scavenging of reactive oxygen species

Cytochrome P450 (P450) enzymes play a significant role in promoting myocardial ischemia-reperfusion (I/R) injury. CYP2C9, an isoform of P450, is known to generate superoxide radicals in the reperfused heart. Sulfaphenazole (SPZ), a CYP2C9 inhibitor, has been shown to decrease I/R injury; however, the mechanism of cardioprotection by SPZ is not well elucidated. The objective of this study was to test whether SPZ mitigates myocardial I/R injury by scavenging reactive oxygen species (ROS). Isolated rat hearts were subjected to 30 min of global ischemia followed by 45 min of reperfusion. Hearts were perfused with SPZ and/or N(omega)-nitro-L-arginine methylester (L-NAME). Coronary flow (CF), left-ventricular developed pressure (LVDP), and rate-pressure product (RPP) were monitored. Superoxide and nitric oxide (NO) generation in the reperfused tissue was determined using fluorescence methods. Myocardial infarct size was measured using triphenyltetrazolium chloride staining. The SPZ-treated group showed a significant recovery of cardiac function compared with the untreated I/R group (CF, 53 versus 45%; LVDP, 48 versus 22%; RPP, 51 versus 20%). The infarct size was significantly reduced in the SPZ-treated group (15%) compared with the I/R control (42%). Coadministration of L-NAME with SPZ significantly attenuated the beneficial effects of SPZ. In addition, SPZ treatment showed significantly decreased superoxide levels and enhanced NO bioavailability in the reperfused heart. In conclusion, the protective effect of SPZ against I/R-mediated myocardial damage appears to be due to a reduction in the superoxide level caused by its inhibition of CYP2C9, as well as scavenging of oxygen free radicals generated in the reperfused heart.     

The infarct size-limiting effect of ischemic postconditioning (IPOC) is suppressed in isolated hyperhomocysteinemic (Hhcy) rat hearts: The reasonable role of PKC-δ

Background

Recently we have demonstrated that the cardioprotective potential of ischemic postconditioning (IPOC) against ischemia and reperfusion (I/R)-induced myocardial injury was markedly suppressed in hyperhomocysteinemic (Hhcy) rat hearts. The present study investigated the possible role of PKC-δ in Hhcy-induced suppression of myocardial infarct size-limiting effect of IPOC.

Methods

Isolated Langendorff's perfused normal and Hhcy rat hearts were subjected to 30-min global ischemia (I), followed by 120-min reperfusion (R). The myocardial damage was assessed by measuring the infarct size, and analyzing the release of LDH and CK-MB in coronary effluent. The oxidative stress in the heart was assessed by measuring lipid peroxidation and superoxide anion generation.

Results

The I/R produced myocardial injury in normal and Hhcy rat hearts by increasing myocardial infarct size, LDH and CK in coronary effluent and oxidative stress. Hhcy rat hearts exhibited enhanced I/R-induced myocardial injury and high oxidative stress as compared to normal rat hearts subjected to I/R. The IPOC (six brief episodes of I/R, 10 s each) afforded cardioprotection against I/R-induced myocardial injury in normal rat hearts; but IPOC-mediated cardioprotection was abolished in Hhcy rat hearts. Treatment with rottlerin (10 μM), a selective inhibitor of PKC-δ, did not affect the cardioprotective effect of IPOC in normal rat hearts; but its treatment significantly restored the myocardial infarct size-limiting effect of IPOC in Hhcy rat hearts.

Conclusion

The high oxidative stress produced in Hhcy rat hearts during reperfusion may activate PKC-δ, which may be responsible for impairing the infarct size-limiting potential of IPOC in Hhcy rat hearts.     

Role of myocardial nitric oxide in diabetic ischemia-reperfusion dysfunction: studies in mice with myocyte-specific overexpression of endothelial nitric-oxide synthase

We investigated the role of nitric oxide (NO) in myocardial ischemia-reperfusion injury of diabetic mice with myocyte-specific overexpression of endothelial NO synthase (NOS). Four weeks after diabetes induction with streptozotocin (blood glucose approximately 29 mM), isolated isovolumic heart function and cellular NO metabolites in response to brief normothermic ischemia-reperfusion were determined. Under normoxic conditions transgenic (TG) hearts from nondiabetic and diabetic animals generated less left-ventricular developed pressure compared with wild-type (WT) control hearts, and this abnormality was unaffected by NOS inhibition. During ischemia, the rise in end-diastolic pressure was less in the TG than WT group of nondiabetic hearts, whereas the transgene had no effect in the diabetic group. Similarly, the transgene also improved reperfusion systolic and diastolic function in nondiabetic but not in diabetic hearts. NOS inhibition worsened reperfusion function in diabetic hearts. Postischemic nitrite and cGMP formation were higher in nondiabetic TG than WT hearts, but in diabetic hearts cGMP was no longer elevated. The formation of reactive oxygen species (superoxide and peroxynitrite) during early reperfusion, measured by electron spin resonance spectroscopy, was similar in nondiabetic WT and TG hearts, but it was significantly higher in diabetic TG hearts. Stimulating endogenous NO production with 10 microM bradykinin more strongly reduced myocardial O(2) consumption in diabetic TG than diabetic WT hearts perfused in normoxia, whereas there was no difference after ischemia-reperfusion. Thus, providing additional endogenous NO is sufficient to protect nondiabetic hearts against ischemia-induced injury, but for a similar protection in diabetic hearts, effective scavenging of reactive oxygen species is also important.     

Effects of melatonin and caffeic acid phenethyl ester on testicular injury induced by myocardial ischemia/reperfusion in rats

Experimental studies indicate that ischemia/reperfusion (I/R) causes remote organ injury although the molecular mechanism has not been clearly defined. In this report, the role of oxidative injury on testicular damage following myocardial I/R injury and the effects of antioxidant agents, melatonin and caffeic acid phenethyl ester (CAPE), on testicular injury were investigated. As far as we know, this is the first report demonstrating that myocardial I/R induces damage to the testes. Thirty-two male Wistar rats were randomly divided into four groups: sham operation (SO), I/R + vehicle, I/R + melatonin, and I/R + caffeic acid phenethyl ester. To produce cardiac damage, the left main coronary artery was occluded for 30 min, followed by 120 min reperfusion, in anesthetized rats. Serum nitric oxide (NO) and malondialdehyde (MDA) levels and morphological changes were examined. I/R was accompanied by a significant increase in serum MDA and NO levels, whereas, melatonin and CAPE administration significantly reduced these values. Melatonin was more efficient in reducing MDA levels than CAPE (P < 0.05). I/R induced myocardial damage, manifested as the histopathological evidence of intracellular vacuolization, interstitial edema, neutrophil infiltration and coagulative necrosis. I/R + vehicle group showed many histological alterations such as focal tubular atrophy, and degeneration and disorganization of the seminiferous epithelium in testes. The number of atrophic tubules and degenerating cells was significantly higher in I/R + vehicle group than that of SO group. Melatonin and CAPE significantly reduced the number of degenerating cells; additionally, melatonin reduced the number of atrophic tubules (P < 0.05). Our results indicate that myocardial I/R induces severe testicular damage and antioxidant agents, especially melatonin, have protective effects on testicular injury after myocardial I/R. Our data emphasize that oxygen-based reactants may play a central role in remote organ injury.     

Possible involvement of PKC-δ in the abrogated cardioprotective potential of ischemic preconditioning in hyperhomocysteinemic rat hearts

The present study has been designed to investigate the possible role of protein kinase C-delta (PKC-δ) in hyperhomocysteinemia-induced attenuation of cardioprotective potential of ischemic preconditioning (IPC). Rats were administered l-methionine (1.7 g/kg/day, p.o.) for 4 weeks to produce hyperhomocysteinemia. Isolated Langendorff perfused normal and hyperhomocysteinemic rat hearts were subjected to global ischemia for 30 min followed by reperfusion for 120 min. Myocardial infarct size was assessed macroscopically using triphenyltetrazolium chloride (TTC) staining. Coronary effluent was analyzed for lactate dehydrogenase (LDH) and creatine kinase (CK) release to assess the degree of cardiac injury. Moreover, the oxidative stress in heart was assessed by measuring lipid peroxidation and superoxide anion generation. The ischemia-reperfusion (I/R) was noted to produce myocardial injury as assessed in terms of increase in myocardial infarct size, LDH and CK in coronary effluent and oxidative stress in normal and hyperhomocysteinemic rat hearts. In addition, the hyperhomocysteinemic rat hearts showed enhanced I/R-induced myocardial injury with high degree of oxidative stress as compared with normal rat hearts subjected to I/R. Four episodes of IPC (5 min each) afforded cardioprotection against I/R-induced myocardial injury in normal rat hearts as assessed in terms of reduction in myocardial infarct size, LDH, CK and oxidative stress. On the other hand, IPC mediated myocardial protection against I/R-injury was abolished in hyperhomocysteinemic rat hearts. Treatment with rottlerin (10 μM), a selective inhibitor of PKC-δ did not affect the cardioprotective effects of IPC in normal rat hearts; but its treatment significantly restored the cardioprotective potentials of IPC in hyperhomocysteinemic rat hearts. The high degree of oxidative stress produced in hyperhomocysteinemic rat hearts during reperfusion may activate PKC-δ, which may be implicated in the observed paradoxically abrogated cardioprotective potentials of IPC in hyperhomocysteinemic rat hearts.     

缓激肽在苯那普利抗大鼠心肌缺血再灌注损伤中的作用

目的：探讨缓激肽在苯那普利抗大鼠心肌缺血再灌注损伤中的作用。方法：应用Langendorff离体装置，采用完全停灌复灌的方法制作心肌缺血再灌注模型，将24只SD大鼠随机平均分对照组（A），苯那普利组（B），苯那普利加缓激肽受体拮抗剂（Hoe140）组（C）。观察心律失常，冠脉流出量，心肌丙二醛（MDA），超氧化物歧化酶（SOD），一氧化氮（NO）含量和心肌超微结构。结果：（1）心律失常：再灌注60rain内，B组室速（VT）和室颤（VF）发生率均明显低于A组，C组上述指标均明显高于B组；（2）冠脉流出量（CF）：B组均明显高于A组，C组均明显低于B组；（3）MDA、SOD、NO含量：B组MDA明显低于A组，SOD和NO均明显高于A组。C组MDA明显高于B组，SOD和NO均明显低于B组；（4）心肌超微结构：B组心肌损伤明显轻于A组，C组损伤重于B组。结论：苯那普利抗心肌缺血再灌注损伤作用和抑制缓激肽降解有关。     

Emulsified isoflurane protects rat heart in situ after regional ischemia and reperfusion

Volatile anesthetic postconditioning reduces myocardial infarct size against ischemia/reperfusion (I/R) injury. We tested the hypothesis that emulsified isoflurane (EIso) administrated after ischemia exerts cardioprotection in a rat model of myocardial I/R. Male SD rats underwent 30‐min coronary occlusion followed by 3‐h reperfusion except for sham rats. All vehicles were administrated intravenously at reperfusion onset for 30 min. In the first study, 56 rats were given saline (CON), 30% intralipid (IL) and 1, 2, 4, 8 or 16 mL/kg EIso for infarct size measurement. In a second study, 32 rats were randomized to four groups and administrated saline in sham (sham) and control (CON) groups, 30% intralipid in IL group and 2 mL/kg emulsified isoflurane in EIso group. Cardiomyocytic enzyme activity was determined. Myocardial mitochondria and cytosol were isolated to determine mitochondrial energy metabolism, cytochrome c release, mitochondrial membrane potential (ΔΨm) and opening of the mitochondrial permeability transition pore (mPTP). Morphologic changes in mitochondria were observed by transmission electron microscopy. Compared with CON and IL, 2, 4 and 8 mL/kg EIso limited infarct size (P < 0.01). Serum levels of cardiac enzyme leakage were reduced in EIso‐treated hearts compared with CON (P < 0.01 or P < 0.05). EIso preserved the ultrastructure of mitochondria, protected against mPTP opening, decreased cytochrome c release and preserved ATP production and ΔΨ_m. In conclusion, EIso is effective in reducing infarct size and in preserving mitochondrial function after ischemia and reperfusion injury.