条件培养液预处理对乳鼠心肌细胞缺氧复氧损伤的影响及其机理探讨

目的观察短暂缺氧条件培养液对乳鼠心肌细胞缺氧复氧损伤的影响，并探讨其作用机理。方法采用乳鼠心肌细胞缺氧／复氧（A／R）损伤模型。用短暂缺氧条件培养液进行预处理。结果条件培养液预处理能够提高A／R损伤后心肌细胞存活率（7638±4．12vsA／R组56．87±3．17％，P＜0．01），减少细胞MDA产生（0．91±0．05VSA／R组1．61±0．06nmol／mg·pr，P＜0．01），减少LDH漏出（35．12±845vsA／R组56．47±9．15U／L，P＜0．01）及细胞内蛋白漏出（0．32±0．04vsA／R组0．43±0．07，P＜0．01）。PKC抑制剂（H_7）完全阻断条件培养液预处理的上述保护作用。结论条件培养液对乳鼠心肌细胞的缺氧复氧损伤具有保护作用，其机理是通过PKC介导的。     

预处理对心肌细胞的保护作用

为探讨缺氧和缺血预处理对心肌细胞的保护作用,分别在培养的乳鼠心肌细胞缺氧／复氧模型、离体大鼠灌注和在体大鼠心肌缺血／再灌注模型中,观察缺血和缺氧预处理对心肌细胞再次长时间缺氧／复氧或缺血／再灌注损伤的保护作用,结果发现,在培养原乳鼠心肌细胞中,缺氧预处理组细胞存活率和超氧化物歧化酶含量较缺氧／复氧组增加（Ｐ〈０．０１）,乳酸脱氢酶的释放和丙二醛含量则减少（Ｐ〈０．０１）。对离体或在体大鼠心脏的缺血     

腺病毒介导HIF-1基因转染对心肌细胞缺血再灌注损伤的保护作用

目的：研究腺病毒介导缺氧诱导因子-1α基因转染对心肌细胞缺血再灌注损伤的保护作用。方法：采用纯化培养的新生大鼠心肌细胞建立缺血再灌注损伤模型,实验分6组：正常细胞培养组,缺氧复氧损伤模型组（I／R组）,基因转染小、大剂量组（AdHIF-1α组,MOI50,100）,转染腺病毒空载体组（AdBlank组）,转染HIF-1α核酶基因组（AtHIF-1α组）。测定各组缺氧复氧后细胞损伤指标乳酸脱氢酶（LDH）、丙二醛（MDA）含量及细胞活性情况。结果：AdHIF-1α组（MOI50,100）较I／R组、AdBlank组、AtHIF-1α组LDH、MDA明显降低,细胞活性高（P〈0．05）。结论：腺病毒介导HIF-1α基因转染心肌细胞具有抗缺血再灌注损伤、保护心肌的作用。     

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。     

缺血预适应后离体鼠心生理功能及形态学改变的实验观察

本实验旨在了解离体鼠心缺血预适应后心肌收缩功能和形态学的改变。方法：通过测定LVDP、dp／dt。RPP等心功能指标，以及形态学评级来评价单纯全心缺血30分钟并再灌注60分钟（B组，n=10）与缺血预适应（C组，n=11）对心肌收缩功能和心肌细胞超微结构的影响。结果：复灌30分钟时缺血预适应组的LVDP、dp／dt、RPP恢复百分率高于对照组（P＜0.05。电镜下心肌细胞的损伤评级缺血预适应组低于对照组（P＜0．05）．结论：缺血预适应能加强离体鼠心全心缺血后心肌收缩功能的恢复，减轻心肌细胞的损伤。     

不同七氟醚缺血处理方式对大鼠离体心脏缺血再灌注损伤的作用及其对基因表达谱的影响

目的：比较七氟醚缺血预处理（ SpreC）、七氟醚缺血后处理（ SpostC）及SpreC＋SpostC对大鼠离体心脏缺血再灌注损伤（ MIRI）的保护作用及其对心肌基因表达谱的影响。方法自主跳动的40只大鼠离体心脏经10 min平衡期灌注后,随机分为4组：对照（ CTRL）组、SpreC组、SpostC组和SpreC＋SpostC组。观察各组平衡期、缺血前及复灌15、60、120 min的血流动力学指标变化;各组缺血后复灌15 min,检测左室心肌烟酰胺腺嘌呤二核苷酸（ NAD＋）水平;平衡期和复灌120 min取各组冠状动脉流出液,检测乳酸脱氢酶（ LDH）和磷酸肌酸激酶（ CK-MB）水平;复灌120 min时测定心肌梗死面积及左室心肌取材行全基因芯片表达谱分析。结果与CTRL组比较,SpreC组、SpostC组和SpreC＋SpostC组心脏功能改善、梗死面积减小、LDH及CK-MB水平降低（P均＜0．05）,且SpreC＋SpostC的心肌保护效果优于单纯SpreC或SpostC（ P均＜0．05）。 SpreC组、SpostC组和SpreC＋SpostC组心脏NAD＋水平均高于CTRL组（P均＜0．05）,且SpreC＋SpostC组高于SpreC或SpostC组（P均＜0．05）。基因谱分析显示,仅有少数基因同时受SpreC、SpostC和SpreC＋SpostC同向调节。结论 SpreC和SpostC 能为大鼠离体心脏的MIRI提供程度相近的保护作用,二者联合应用效果更佳。不同七氟醚缺血处理方式对MIRI后心肌基因表达谱的影响不同。     

苯那普利后处理对离体大鼠心肌缺血再灌注损伤的保护作用

目的观察苯那普利后处理对离体大鼠心肌缺血再灌注（I／R）损伤的保护作用，初步探讨其可能的作用机制。方法应用Langendroff离体灌流装置，采用完全停灌复灌方法制作离体大鼠心肌缺血再灌注模型。32只SD大鼠随机等分为4组：对照组、I／R组、缺血预处理组和苯那普利后处理组。测定各组稳灌20min和再灌60min时的冠脉流量，改良亮绿变色酸法（GCA）观察心肌损害程度，免疫组化法检测心肌组织中核因子-κB（NF—κB）和肿瘤坏死因子（TNF—α）的表达。结果与对照组比，I／R组，再灌注60min时的冠脉流量减少（P〈0．01），心肌损害程度增加（P〈0．01），免疫组织化学染色可见NF—κB蛋白表达显著增强且主要表达在心肌细胞核（P〈0．01），TNF—α主要表达在心肌细胞胞质，呈强阳性。与I／R组相比，苯那普利后处理组再灌注60min时的冠脉流量增多[（4．3±0．4）ml／min和（3．5±0．5）ml／min，P〈0．05]，GCA染色心肌变性减轻，阳性率减低（14％±7％和40％±7％，P〈0．01），NF—κB表达减少（34．8％±4．7％和49．3％±9．7％，P〈0．05），TNF—α表达为弱阳性。苯那普利后处理组和预处理组相比较，差异无统计学意义（P〉0．05）。结论苯那普利后处理对缺血再灌注心肌具有保护作用，其机制可能与苯那普利后处理抑制NF—κB活性，减少TNF—α的表达有关。     

茶多酚对大鼠肝脏缺血-再灌注损伤的保护作用

目的探讨茶多酚对大鼠肝脏缺血再灌注损伤的保护作用及其机制。方法健康雄性SD大鼠30只，随机均分为4组：假手术正常对照组6只；肝脏缺血再灌注损伤模型组8只；茶多酚低浓度于预组8只（75mg／kg）；茶多酚高浓度于预组8只（150mg／kg）．缺血30min再灌注60min检测肝组织MDA含量、GSH-PX活性及血浆ALT含量。光镜下比较各组肝组织损伤情况。结果肝缺血再灌注模型组ALT、MDA含量明显高于假手术正常对照组（P〈0．01），GSH-PX活力则降低（P〈0．01）；茶多酚低浓度及高浓度组ALT，MDA含量均明显低于肝缺血再灌注模型组（P〈0．01），而GSH-Px活力均高于肝缺血再灌注模型组（P〈0．01）；光镜观察茶多酚低浓度及高浓度预处理组肝细胞损伤明显小于肝缺血再灌注模型组。结论茶多酚对大鼠肝脏缺血再灌注损伤具有显著的保护作用。     

参附注射液对犬心肌缺血/再灌注损伤的保护作用

目的探讨参附注射液（SFI）预处理对犬心肌缺血／再灌注损伤的保护作用及机制。方法21只犬随机分为3组。假手术组（Sham组）、缺血/再灌注组（I／R组）和参附注射液（SFI）预处理组（SFI纽）。观察血清乳酸脱氢酶（LDH）、肌酸磷酸激酶同工酶（CK-MB）和心肌钙蛋白（cTn-I）含量,测定心肌梗死范围、心肌组织丙二醛（MDA）含量和超氧化物歧化酶（SOD）活性等指标。结果与Sham组比较,I／R组和SFI组LDH、CK-MB和cTn-I值均明显升高,心肌组织SOD活性显著下降,MDA含量显著升高,心肌梗死范围明显增大（P〈0．01）。与I／R组比较,SFI纽能显著降低血清LDH、CK-MB、cTn-I值和心肌组织MDA含量（P〈0．01）,显著缩小心肌梗死范围（P〈0．05）,升高心肌SOD活性（P〈0．05）。结论SFI预处理对心肌缺血／4g灌注损伤心肌有保护作用,机制可能与减轻脂质过氧化反应有关。     

缺血预处理对糖尿病大鼠心肌梗死和细胞因子的影响

目的 观察大鼠心肌梗死面积和细胞相关因子的变化,探讨缺血预处理（IP）对缺血－再灌注（I／R）糖尿病大鼠心肌的保护作用。方法 向健康SD大鼠腹腔内注射链脲佐菌素（每只60mg/kg）制造糖尿病大鼠模型。2d后测定血糖,将血糖≥11．1mmol/L定为糖尿病鼠,共39只。2周后,麻醉大鼠。开胸结扎冠状动脉左前降支（LADCA）复制IP和I／R模型。将39只糖尿病大鼠分为IP组、非缺血预处理（NIP）组、对照组,每组13只。记录Ⅱ导联心电图,测定心腔血清肌酸激酶同工酶（CK－MB）、白细胞介素－8（IL－8）、肿瘤坏死因子α（TNFα）、心肌组织丙二醛（MDA）、超氧化物歧化酶（SOD）含量。取心脏切片染色,计算心肌缺血范围和心肌坏死范围。结果 IP组和NIP组间心肌缺血范围分别为46．6％和48．6％,无显著性差异,心肌坏死范围分别为64．8％和32．6％9P＜0．01）。IP组再灌注期室性心律失常减少,尤其是室颤较NIP组显著减少52．9％（P＜0．01）。IP组CK－MB和TNFα及MDA显著低于NIP组（P＜0．05）。结论 缺血预处理可通过减少TNFα和抗氧化作用,减少心肌坏死范围和降低糖尿病大鼠室颤的发生,从而减轻糖尿病大鼠心肌I／R的严重损害。     

不同缺血预处理对未成熟心肌细胞功能的影响

目的比较不同方法的缺血预处理对未成熟心肌细胞功能的影响。方法采用Langendorff离体心脏灌注模型。分为4组:缺血/再灌注(I/R)组,离体心脏灌注15min转为工作心15min后停灌45min,恢复灌注15min改为工作心30min;心脏缺血预处理(MIP)组:离体心脏灌注15min转为工作心15min后反复2次缺血5min/再灌注5min,然后重复I/R组缺血/再灌注方法;肾缺血预处理(RIP)组:反复三次阻断左肾动脉5min,放开5min,切取心脏,重复I/R组方法;双下肢缺血预处理(DLIP)组:反复3次捆扎双下肢5min,松开5min,切取心脏,重复I/R组方法。以血清肌酸激酶(CK)和乳酸脱氢酶(LDH)漏出率、心肌组织三磷腺苷(ATP)和丙二醛(MDA)含量、超氧化物歧化酶(SOD)活性、心肌细胞内Ca2+含量、心肌线粒体Ca2+-ATPase活性及其Ca2+含量、心肌线粒体合成三磷腺苷能力[ATP]m作为观察指标。结果MIP、RIP及DLIP组ATP含量、SOD活性、心肌线粒体Ca2+-ATPase活性、[ATP]m均高于I/R组(P<0.01),MDA含量、CK、LDH漏出率、心肌细胞内Ca2+含量、心肌线粒体Ca2+含量均低于I/R组(P<0.01)。结论肾缺血预处理、双下肢缺血预处理与心脏缺血预处理有同等的心肌细胞保护作用。     

Remote preconditioning by infrarenal aortic occlusion is operative via delta1-opioid receptors and free radicals in vivo in the rat heart

BACKGROUND: Ischemic preconditioning (PC) is a powerful mechanism in reducing infarct size of the heart. Protection can be performed either by an ischemic stimulus of the heart itself or by ischemia of an organ distant to the heart (remote PC). We have previously shown that remote PC by infrarenal occlusion of the aorta [IOA] in the rat is as powerful as classical ischemic PC. This protection may be transmitted by humoral factors, and protein kinase C is a mediator in the signal transduction mechanism. Focus of the present study was to address the question whether remote preconditioning is dependent on the activation of the delta1-opioid receptor and/or free radicals, the infarct size was determined after either inhibition of the delta1-opioid receptor or scavenging free radicals. METHODS AND RESULTS: IOA was performed in rats by occlusion of the infrarenal aorta for 15 min followed by a 10-min reperfusion period. Infarction of the heart was induced by 30 min regional ischemia followed by 30 min of reperfusion. The area of infarct was determined by propidium iodide and the risk zone was demarcated by zinc cadmium sulfide fluorescent particles. Control hearts (30 min regional ischemia of the heart followed by 30 min of reperfusion; no IOA) had an infarct size of 54 +/- 3%, whereas classical preconditioning by three ischemia/reperfusion [I/R] cycles, 5 min each, reduced it to 12 +/- 1% of the risk zone (p<0.05). Fifteen minutes IOA with 10 min of reperfusion was highly protective and reduced the infarct size to 20 +/- 5% (p<0.05 vs. control). Inhibition of the delta1-opioid receptors by 7-benzylidenenaltrexone [BNTX] blocked the protection obtained by PC and IOA (41 +/- 4% and 44 +/- 2%, respectively; p<0.05 vs. the group without BNTX). BNTX in control hearts had no influence on infarct size (52 +/- 2%). Inhibition of endogenously released radicals by N-2-mercaptopropionyl glycine [MPG] blocked the infarct size reduction of IOA (46 +/- 3%; p<0.05 vs. IOA), but had no influence on the protection in classically preconditioned hearts protected by three cycles I/R (13 +/- 4%). Only if the number of the preconditioning stimuli was reduced to one was MPG able to overcome the protection (43 +/- 4%, p<0.05 vs. PC with one I/R cycle (21 +/- 4%)). CONCLUSION: Remote preconditioning using IOA protects the rat heart from infarction. Classical and remote PC share both the delta1-opioid-receptor and free radicals as common elements in their signal transduction pathways. MPG can block protection from IOA and from one, but not from three, classical preconditioning cycles. This indicates that the protection by remote preconditioning is comparable to classical PC with one I/R cycle.     

细胞膜钠钙交换蛋白在大鼠心肌缺血预适应及腺苷诱导预适应中的作用及其信号转导

目的 探讨细胞膜钠钙交换蛋白（NCX）在心肌缺血预适应及药物诱导预适应中的作用及可能的信号转导途径.方法 培养乳鼠心肌细胞随机分为缺血/再灌注组、缺血预适应组、腺苷预处理组、钙调素依赖蛋白激酶Ⅱ（CaMKⅡ）抑制剂KN-93＋缺血预适应组、KN-93＋腺苷预处理组及对照组.各组乳酸脱氢酶（LDH）漏出量用生化法测定（n=5）,钠钙交换蛋白mRNA表达以半定量RT-PCR检测（n=5）,NCX活性以液闪仪测定Na^＋依赖的^45Ca^2＋摄取率表示（n=5）.结果 （1）缺血/再灌注组LDH漏出量显著增加（P＜0.05）,缺血预适应及腺苷预处理组LDH漏出量均显著降低 （P＜0.05）;KN-93预作用后,缺血预适应及腺苷预处理组LDH漏出量均显著增加（P＜0.05）. （2）缺血/再灌注组NCX ^45Ca^2＋摄取率比对照组高（P＜0.005）.缺血预适应及腺苷预处理组较缺血/再灌注时NCX ^45Ca^2＋摄取率显著低（P＜0.05）,且腺苷预处理组NCX ^45Ca^2＋摄取率较缺血预适应组更低（P＜0.05）. KN-93＋缺血预适应组与缺血/再灌注组NCX ^45Ca^2＋摄取率差异无统计学意义, KN-93＋腺苷预处理组较缺血/再灌注组NCX ^45Ca^2＋摄取率低（P＜0.05）.（3） 缺血/再灌注组NCX mRNA的表达比对照组显著高（P＜0.05）;缺血预适应及腺苷预处理组NCX mRNA的表达均显著低（P＜0.05）;KN-93处理后缺血预适应组及腺苷预处理组NCX mRNA的表达水平显著高（P＜0.05）,且腺苷预处理组NCX mRNA的表达较缺血预适应组更高（P＜0.05）.结论 缺血预适应及腺苷预处理对心肌的保护作用与细胞膜NCX有关,缺血预适应中NCX对心肌损伤保护作用经CaMKⅡ介导,而在腺苷预处理中NCX对心肌损伤保护作用仅部分经CaMKⅡ介导.     

Activation of mitochondrial K(ATP) channel elicits late preconditioning against myocardial infarction via protein kinase C signaling pathway

Activation of mitochondrial K(ATP) (mitoK(ATP)) channel induces acute ischemic preconditioning (PC) against ischemic injury. The ability of this channel to elicit late PC remains unknown. The present study tests the hypothesis that stimulation of mitoK(ATP) channel induces late PC via the protein kinase C (PKC) signaling pathway. Rats were subjected to 30 minutes of regional ischemia and 120 minutes of reperfusion (I/R). In other groups, rats were pretreated with diazoxide, a specific opener of the mitoK(ATP) channel (7 mg/kg, IV), 12, 24, 48, and 72 hours before they were subjected to I/R. A maximum reduction in infarct size was observed after 24 hours (33.3+/-2.2% versus I/R group, 62.1 +/-2.4%). Pretreatment with diazoxide did not reduce the infarct size significantly after 12, 48, and 72 hours (50.2+/-4.3%, 50.5+/-4.6%, and 58.2+/-4.9%) compared with the I/R group. The protection was blocked with 5-hydroxydecanoic acid (5-HD, 5 mg/kg IV), a relatively selective mitoK(ATP) channel blocker (56.5+/-2.7%), and chelerythrine (5 mg/kg IV), an effective PKC inhibitor (57.1+/-3.4%) administered either on the first day before diazoxide pretreatment or 10 minutes before I/R on the second day. Cell necrosis was decreased by approximately 50% in the diazoxide preconditioned hearts compared with control I/R hearts. Cell death by apoptosis was also significantly decreased in diazoxide pretreated hearts (3.2%) as compared with I/R (11.3%). In conclusion, activation of mitoK(ATP) channel with diazoxide produces late PC against reperfusion injury. The effect of mitoK(ATP) channel appears to be dependent on the PKC-mediated signal pathway.     

葡萄糖酸镁对离体大鼠心肌缺血再灌注细胞凋亡和Fas及FasL的影响

目的观察葡萄糖酸镁对离体大鼠心肌缺血再灌注细胞凋亡和Fas/FasL水平是否存在影响及其可能机制。方法48只雄性SD大鼠随机分为3组:对照组,缺血再灌注组(I/R组),葡萄糖酸镁组。实验1:每组取8只大鼠,对照组用改良的K-H液持续灌注110 min;I/R组用改良的K-H液灌流20 min后,停灌30 min,再灌注60 min;葡萄糖酸镁组改良的K-H液中加入葡萄糖酸镁2.4 mmol/L,余同I/R组。检测心肌灌流液中肌酸激酶(CK),乳酸脱氢酶(LDH)含量,心肌组织中总超氧化物歧化酶(T-SOD)、丙二醛(MDA)含量。实验2:取每组其余8只大鼠,实验过程类似实验1,不同点是其再灌注时间改为120 min。实验结束检测心肌Fas和FasL蛋白表达及心肌细胞凋亡指数。观察实验1、2再灌注20min内心律失常发生情况。结果与I/R组比较,葡萄糖酸镁组心律失常发生率显著下降(P<0.01);再灌流出液中CK、LDH含量明显降低(P<0.01);心肌组织T-SOD活性显著升高(P<0.01),MDA含量、Fas/FasL蛋白表达及细胞凋亡指数明显降低(P<0.01)。结论葡萄糖酸镁可清除氧自由基,干预Fas/FasL的表达从而减少心肌细胞凋亡。     

No loss of cardioprotection by postconditioning in connexin 43-deficient mice

In situ hearts and isolated cardiomyocytes from heterozygous connexin 43-deficient (Cx43+/-) mice cannot be protected by ischemic preconditioning or diazoxide. We have now addressed the role of connexin 43 in ischemic postconditioning (PC). Wild type (WT) and Cx43+/- mice were subjected to 30 min coronary occlusion and 120 min reperfusion, with and without a PC protocol of three cycles of 10 s coronary occlusion/10 s reperfusion. Infarct size (TTC staining) was reduced by PC from 54+/-5 to 37+/-3% of area at risk in WT. Likewise, infarct size was reduced by PC from 53+/-4 to 34+/-3% of area at risk in Cx43+/-. We conclude that connexin 43 is no prerequisite for PC's protection. To this end, the signal transduction of ischemic preconditioning and postconditioning differs.     

Effect of Chronic CPT-1 Inhibition on Myocardial Ischemia-Reperfusion Injury (I/R) in a Model of Diet-Induced Obesity

Purpose

By increasing circulating free fatty acids and the rate of fatty acid oxidation, obesity decreases glucose oxidation and myocardial tolerance to ischemia. Partial inhibition of fatty acid oxidation may improve myocardial tolerance to ischemia/reperfusion (I/R) in obesity. We assessed the effects of oxfenicine treatment on post ischemic cardiac function and myocardial infarct size in obese rats.

Methods

Male Wistar rats were fed a control diet or a high calorie diet which resulted in diet induced obesity (DIO) for 16?weeks. Oxfenicine (200?mg/kg/day) was administered to control and DIO rats for the last 8?weeks. Isolated hearts were perfused and infarct size and post ischemic cardiac function was assessed after regional or global ischemia and reperfusion. Cardiac mitochondrial function was assessed and myocardial expression and activity of CPT-1 (carnitine palmitoyl transferase-1) and IRS-1 (insulin receptor substrate-1) was assessed using Western blot analysis.

Results

In the DIO rats, chronic oxfenicine treatment improved post ischemic cardiac function and reduced myocardial infarct size after I/R but had no effect on the cardiac mitochondrial respiration. Chronic oxfenicine treatment worsened post ischemic cardiac function, myocardial infarct size and basal mitochondrial respiration in control rat hearts. Basal respiratory control index (RCI) values, state 2 and state 4 respiration rates and ADP phosphorylation rates were compromised by oxfenicine treatment.

Conclusion

Chronic oxfenicine treatment improved myocardial tolerance to I/R in the obese rat hearts but decreased myocardial tolerance to I/R in control rat hearts. This decreased tolerance to ischemia of oxfenicine treated controls was associated with adverse changes in basal and reoxygenation mitochondrial function. These changes were absent in oxfenicine treated hearts from obese rats.     

脂质胞壁酸诱导的预适应对自发性高血压大鼠心肌缺血再灌注损伤的保护作用

目的:探讨脂质胞壁酸(LTA)诱导的延迟预适应对自发性高血压大鼠(SHR)心脏缺血/再灌注(I/R)损伤的保护作用及诱导型一氧化氮合酶(iNOS)是否参与其作用。方法:采用结扎左冠状动脉前降支30min,再灌注复制大鼠心肌I/R模型,结扎前24h注射LTA,检测心肌再灌注60min后血清心肌型肌酸激酶同工酶(CK-MB)、乳酸脱氢酶(LDH),并用dUTP缺口末端标记法检测心肌细胞凋亡,用Western Blot方法检测凋亡蛋白Bcl-2和Bax的蛋白表达。同时采用实时RT-PCR技术和Western Blot方法分别检测心肌再灌注末iNOS mRNA和蛋白的表达。结果:与I/R组比较,LTA预适应组能显著减少室性心律失常(VA)评分值(P<0.01);LTA预适应还能明显减少I/R后血清CK-MB和LDH的漏出(P<0.01,P<0.05),减少心肌细胞凋亡(P<0.01),凋亡相关蛋白Bcl-2表达明显上调(P<0.01),而Bax蛋白表达则下调(P<0.01)。再灌注末,预适应组iNOS mRNA的平均相对表达量较I/R组增加了0.71倍(P<0.01),LTA预适应组iNOS蛋白的表达量较I/R组增加了0.96倍(P<0.05)。不论在LTA预适应前或缺血前期给予iNOS抑制剂氨基胍或是单独给予氨基胍,上述观测指标均与I/R组比较差异无统计学意义。结论:LTA预适应能显著减轻SHRI/R导致肥厚心肌的坏死和细胞凋亡,iNOS/NO作为触发和效应环节在介导LTA预适应中发挥关键作用。     

牛膝多肽通过抑制氧化应激减轻大鼠心肌缺血/再灌注损伤

目的 探讨牛膝多肽（ABPP）预处理对心肌缺血/再灌注（MI/R）损伤的影响及其机制。方法 建立大鼠MI/R模型,将成年SD大鼠随机分为 Sham（假手术）组、MI/R组、药物预处理（ABPP＋MI/R）组。检测血流动力学、用氯化三苯基四氮唑和伊文思蓝双染法检测心肌梗死(MI)面积、以血浆肌酸激酶（CK）和乳酸脱氢酶（LDH）活性检测心肌损伤情况、以超氧化物、丙二醛（MAD）和超氧化物歧化酶（SOD）含量检测心肌氧化应激以及Western blot方法测定心肌组织中gp91phox的表达。用TUNEL法检测心肌细胞的凋亡指数(AI),荧光分析法检测caspase 3活性。结果 与MI/R组比较,ABPP预处理使左心室上升、下降最大速率（±LVdP/dtmax）升高（P<0.05）,MI面积显著减少〔MI/R组为（36.0±3.0）%,ABPP组为（26.5±3.5）%,P<0.05〕,血浆CK和LDH水平分别降低到（1251±72）U/L和（1961±122）U/L（P<0.05）,TUNEL阳性染色显著降低（P<0.05）,caspase-3的活性增加（P<0.05）,超氧化物蓄积减少（P<0.05）,显着降低了gp91phox的表达（P<0.05）,MDA的含量显著减少（P<0.05）,SOD活性增加（P<0.05）。结论 ABPP降低氧化应激和对MI/R损伤的心肌具有保护作用。