Melatonin decreases production of hydroxyl radical during cerebral ischemia-reperfusion

目的：研究褪黑激素（ｍｅｌａｔｏｎｉｎ）对大鼠脑缺血再灌注中羟自由基生成的影响．方法：采用栓线法阻塞左侧ＭＣＡ３０ｍｉｎ再灌注模型．通过水杨酸捕获法与微透析技术结合来观察缺血再灌中羟自由基含量的变化．结果：ＤＨＢＡ水平在缺血１５ｍｉｎ后显著升高，持续到再灌注后３０ｍｉｎ仍维持较高水平．缺血前３０ｍｉｎ给予ｍｅｌａｔｏｎｉｎ（４ｍｇ·ｋｇ－１，ｓｃ）显著降低缺血１６－３０ｍｉｎ及再灌注１－３０ｍｉｎ时ＤＨＢＡ的含量．结论：Ｍｅｌａｔｏｎｉｎ对大鼠缺血再灌中羟自由基的产生有抑制作用．     

Effect of melatonin on production of hydroxyl radical and lactate dehydrogenase during hypoxia in rat cortical slices 1

目的：研究褪黑激素对大鼠大脑皮层脑片在缺氧后羟自由基及乳酸脱氢酶生成的影响．方法：通过水杨酸捕获法来观察缺氧再给氧中羟自由基含量的变化．脑片通以９１６％Ｎ２＋８４％Ｏ２造成缺氧．ＬＤＨ用细胞毒检测盒测定．结果：ＤＨＢＡ水平在缺氧及再给氧后显著升高;缺氧时给予褪黑激素可以浓度依赖性地降低再给氧１５ｍｉｎ时ＤＨＢＡ的含量,但对缺氧３０ｍｉｎ时ＤＨＢＡ的含量没有显著作用．ＬＤＨ的含量在缺氧后１ｈ内持续升高;褪黑激素可以显著降低缺氧后ＬＤＨ的释放．结论：褪黑激素降低大鼠缺氧后的损伤以及羟自由基的产生．     

褪黑激素对大鼠大脑皮层脑片在缺氧后羟自由基及乳酸脱氢酶生 …

目的 研究褪黑激素对大鼠大脑皮层脑片在缺氧后羟自由基及乳酸脱氢酶生成的影响。方法 通过水杨酸捕获法一观察缺氧再给氧中自由基含量的变化,脑片通以９１．６％,Ｎ２＋８．４％Ｏ２造成缺氧。ＬＤＨ用细胞毒检测盒测定。结果：ＤＨＢＡ水平在缺氧及再给氧后显著升高,缺氧时给予褪黑激素可以浓度依赖性地降低再给氧１５ｍｉｎ时ＤＨＢＡ的含量,但对缺氧３０ｍｉｎ时ＤＨＢＡ的含量没有显著作用,ＬＤＨ的含量在缺氧后１ｈ内持     

沙棘总黄酮对大鼠心肌再灌注损伤的保护作用

目的：观察沙棘总黄酮对大鼠心肌再灌注损伤时超微结构及对心肌组织ＳＯＤ活性和ＭＤＡ含量的影响。方法：预先ｉｇ沙棘总黄酮（ＴＦＨ）６ｄ后，用ＳＤ大鼠制作心肌缺血再灌注模型。结果：缺血４０ｍｉｎ，再灌３０ｍｉｎ后ＴＦＨ（７７ｍｇ·ｋｇ－１、２３１ｍｇ·ｋｇ－１）能明显减轻缺血再灌损伤区超微结构的病理改变，显著提高大鼠心肌组织ＳＯＤ活性并减少ＭＤＡ的生成。结论：ＴＦＨ对大鼠心肌缺血再灌损伤的保护作用可能与提高自由基清除酶活性及抑制脂质过氧化反应有关。     

乙酰香茶菜甲素抗心肌缺血再灌注损伤作用

用麻醉大鼠缺血４０ｍｉｎ，再灌注３０ｍｉｎ所致的心肌缺血再灌注损伤模型，观察了乙酰香茶莱甲素（ＤＡＡ－Ａ）对心肌缺血再灌注损伤的保护作用。ＤＡＡ－Ａ能提高缺血及再灌期左室收缩压（ＬｖＳＰ）及±ｄｐ／ｄｔｍａｘ，降低再灌注所致心律失常发生率，降低血浆中磷酸肌酸激酶（ＣＰＫ）、丙二醛（ＭＤＡ）、血栓素Ｂ２（ＴＸＢ２）的水平，缩小心肌梗塞面积。结果提示：ＤＡＡ－Ａ对心肌缺血再灌注损伤有明显保护作用，其机制与抗脂质过氧化损伤有关．     

前列腺素E_1、川芎嗪合用对大鼠心肌缺血再灌注损伤的保护作用

目的观察前列腺素Ｅ１（３１２５μｇ·ｋｇ－１）与川芎嗪（２５ｍｇ·ｋｇ－１）合用对大鼠心肌缺血再灌注损伤的影响。方法麻醉大鼠冠脉结扎３０ｍｉｎ后，再灌６０ｍｉｎ诱发心律失常，硫代巴比妥酸法和分光光度法分别测定ＭＤＡ、ＳＯＤ及ＧＳＨ Ｐｘ，原子吸收光度法测定心肌细胞内Ｃａ２＋含量。结果两药小剂量合用的效果优于各药较大剂量单用。联合用药不仅更显著提高缺血再灌心肌ＳＯＤ、ＧＳＨ Ｐｘ活力（Ｐ＜００１），尚可显著降低ＭＤＡ、Ｃａ２＋及血清ＣＫ ＭＢ含量（Ｐ＜００１），防止缺血再灌室性心律失常的发生（Ｐ＜００１）。结论前列腺素Ｅ１与川芎嗪合用对心肌缺血再灌注损伤的保护作用有显著的协同作用。其作用与提高自由基清除酶活性、抑制脂质过氧化反应和防止心肌细胞内“钙超负荷”有关     

二乙基二硫代氨基甲酸钠对沙土鼠脑缺血再灌注损伤的影响

沙土鼠脑缺血６０ｍｉｎ后，脑组织氧自由基和ＭＤＡ含量无明显升高，而Ｍｎ－ＳＯＤ的活性下降，缺血６０ｍｉｎ再灌注５ｍｉｎ时，氧自由基显著升高。再灌注３０ｍｉｎ时，氧自由基显著升高，Ｍｎ－ＳＯＤ和Ｃｕ，Ｚｎ－ＳＯＤ活性显著降低。缺血前１５ｍｉｎ，ｉｖＤＴＣ对缺血再灌注脑组织中氧自由基和ＭＤＡ升高有显著抑制作用，对Ｍｎ－ＳＯＤ活性有显著保护作用。且呈剂量依赖关系。     

二乙基二硫代氨基甲酸钠对沙土鼠脑缺血再灌注损伤的保护作用

蒙古沙土鼠脑缺血６０ｍｉｎ后，脑组织能量物质ＡＴＰ、ＡＤＰ明显下降，且有可检测的次黄嘌呤产生；氧在含量上有趋势。再灌注５ｍｉｎ，氧自由基含量显著增加；灌注３０ｍｉｎ时，ＡＴＰ、ＡＤＰ有所回，ＨＸ降至无法检测ＯＦＲ降于缺血组水平。     

苯海索对大鼠急性前脑缺血再灌注损伤的保护

目的：研究苯海索（ｔｒｉｈｅｘｙｐｈｅｎｉｄｙｌ，ＴＨＰ）对大鼠急性前脑缺血再灌注损伤的保护作用。方法：用阻断四血管法造成急性前脑缺血再灌注损伤。ＴＨＰ１．５ｍｇ·ｋｇ－１或３ｍｇ·ｋｇ－１在缺血前５ｍｉｎ，再灌前和再灌注３０ｍｉｎ分３次静脉注射。结果：ＴＨＰ可剂量依赖性阻止脑组织和红细胞中超氧化物歧化酶活力下降及脑组织中乳酸脱氢酶（ＬＤＨ）活力下降，阻止外周血中ＬＤＨ活力增加和过氧化脂质含量增加，并促进脑电活动恢复和抑制脑水肿形成。结论：ＴＨＰ对大鼠急性前脑缺血再灌注损伤具有保护作用，其机制与抗脂质过氧化有关。     

银杏叶提取物预防离体大鼠心肌缺血再灌注损伤

探讨银杏叶提取物在心肌缺血再灌注损伤中的预防作用。方法取３０只ＳＤ大鼠平均为３组,采用改良Ｌａｎｇｅｎｄｏｒｆｆ法建立离体大鼠心脏缺血再灌注模型,以Ｋｒｅｂｓ－Ｈｅｎｓｅｌｅｉｔ碳酸氢盐酸冲液（ＫＨＢＢ）灌注１０ｍｉｎ后,实验组和对照组分别予以Ｅｇｂ７６１加晶体停搏液或晶体停搏液停搏,停搏６０ｍｉｎ后再以ＫＨＢＢ缓冲灌注６０ｍｉｎ,在复灌１５、３０、６０ｍｉｎ时点测定冠脉量,心率、左心室压力,心收     

Aniracetam,a Pyrrolidinone-type Cognition Enhancer,Attenuates the Hydroxyl Free Radical Formation in the Brain of Mice with Brain Ischaemia

We demonstrate here that aniracetam has the ability to block the formation of cytotoxic hydroxyl radicals (· OH) during ischaemia-reperfusion of mouse brain. The fact that brain ischaemia for 40 min followed by reperfusion increased ·OH was evidenced by detection of a peaked increase at 20 min after an ischaemic insult in the formation of 2,3-dihydroxy-benzoate (DHBA) from salicylate in cerebroventricular perfusate, a means of monitoring ·OH formation. A clearcut increase in dopamine was also observed during and after brain ischaemia. The ischaemia-reperfusion mice given aniracetam at an intraperitoneal dose of 30 or 100 mg kg^?1 showed a smaller increase in the formation of DHBA than those given the vehicle only. Aniracetam at 100 mg kg^?1 significantly suppressed the formation of DHBA by approximately 80%, becoming evident at 20 min after reperfusion and thereafter. Protection against death in mice insulted with a 40-min brain ischaemia (3/13 vs 13/25) was observed following 100 mg kg^?1 aniracetam. The increase in the dopamine levels was substantially reduced following aniracetam treatment and the reduction became significant at 20 min after reperfusion and thereafter in parallel with attenuation by aniracetam of DHBA formation. This finding suggests that the inhibitory activity of aniracetam in attenuating the hydroxyl free-radical formation in ischaemic mice is probably due, at least in part, to its palliative action on the dopaminergic neurons.     

巴曲酶对脑缺血后沙土鼠海马锥体细胞延迟性坏死的影响

目的研究巴曲酶减轻沙土鼠前脑缺血再灌注损伤的作用及对·ＯＨ产生的影响。方法沙土鼠前脑缺血再灌注损伤模型，观察巴曲酶对脑缺血后沙土鼠脑电各波比率、开阔法行为、残存的海马锥体细胞数目和·ＯＨ含量的变化。结果巴曲酶能减低脑缺血后脑电δ波比率的增高程度，减轻脑缺血后沙土鼠行为受损程度，减少海马ＣＡ１区锥体细胞的死亡数目。巴曲酶还减少脑缺血再灌注后海马·ＯＨ的产生。结论巴曲酶能减轻脑缺血再灌注损伤，其作用可能与其减少氧自由基的产生有关。     

AM-36, a novel neuroprotective agent,profoundly reduces reactive oxygen species formation and dopamine release in the striatum of conscious rats after endothelin-1-induced middle cerebral artery occlusion

Elevated generation of reactive oxygen species (ROS) has been demonstrated during ischemia and reperfusion. Dopamine (DA) autooxidation may contribute to increased ROS generation. The novel neuroprotective agent AM-36 has antioxidant and Na(+) channel blocking activity and reduces neuronal damage in both cortex and striatum after middle cerebral artery (MCA) occlusion. Here we sought in vivo evidence of the ability of AM-36 to inhibit intrastriatal ROS generation and DA release after ischemia. Salicylate hydroxylation coupled with in vivo microdialysis in the striatum of conscious Long Evans rats was performed during MCA occlusion by perivascular microinjection of endothelin-1 (ET-1). AM-36 (6 mg/kg) was administered intraperitoneally 30 min after MCA occlusion. Dialysates were analysed using high performance liquid chromatography with electrochemical detection for the salicylate hydroxylation product, 2,3-dihydroxybenzoic acid (2,3 DHBA) and for DA and metabolites. MCA occlusion resulted in a marked increase in 2,3 DHBA and a secondary increase in all analytes, 180-300 min later. Increased DA release coincided with 2,3 DHBA formation. AM-36 significantly reduced ischemia induced increases in 2,3 DHBA and DA, and infarct volume in the striatum. Significant improvements in a battery of behavioural tests was also found in AM-36 treated rats. This study has demonstrated profound inhibition of ROS generation by a novel compound with antioxidant activity, administered post-ischemia in conscious rats.     

巴曲酶对沙土鼠脑缺血再灌注损伤的影响

研究巴曲酶对脑缺血再灌注所致延迟性神经元死亡的影响以及与ＯＨ·产生的关系． 沙土鼠前脑缺血１０ ｍ ｉｎ 再灌注６０ ｍ ｉｎ． 应用高效液相色谱法测定纹状体多巴胺,海马ＡＴＰ和２,３－二羟基苯甲酸（２,３－ＤＨＢＡ, 反映ＯＨ·含量）的含量． 应用病理方法检查海马ＣＡ１ 区锥体细胞延迟性死亡情况．结果显示, 在再灌注开始时ｉｐ 巴曲酶８ ＢＵ·ｋｇ－ １明显促进海马ＡＴＰ含量的恢复,减少ＯＨ·的产生和纹状体多巴胺的释放． 脑缺血再灌注后ｄ ７ 巴曲酶组（８ ＢＵ·ｋｇ－ １ ｉｐ,每日１ 次,共３ ｄ）海马ＣＡ１ 区存活的锥体细胞数目也明显多于对照组（每１００ 平方微米０．２７±０．１１ ｖｓ ０．０４±０．０３）． 以上结果提示, 巴曲酶可减轻脑缺血再灌注所致的延迟性神经元死亡, 其机理可能与其减少脑缺血再灌注期间ＯＨ·的产生有关．     

Edaravone reduces myocardial infarct size and improves cardiac function and remodelling in rabbits

1. In the present study, we investigated the effect of 3-methyl-1-phenyl-2-pyrazolin-5-one (edaravone), a free radical scavenger, on myocardial infarct (MI) size and cardiac function in an in vivo model of MI in rabbits. We further investigated the contribution of hydroxyl radicals, superoxide and nitric oxide (NO) to its effects. 2. Anaesthetized open-chest Japanese white male rabbits were subjected to 30 min coronary occlusion and 48 h reperfusion. The control group (n = 10) was injected with saline 10 min before reperfusion. The edaravone group (n = 10) was injected with a bolus of 3 mg/kg edaravone 10 min before reperfusion. The edaravone + N(G)-nitro-L-arginine methyl ester (L-NAME) group (n = 5) was given 10 mg/kg, i.v., L-NAME 10 min before the administration of 3 mg/kg edaravone. The L-NAME group (n = 5) was given 10 mg/kg, i.v., L-NAME 20 min before reperfusion. Infarct size was measured using the triphenyl tetrazolium chloride method and is expressed as a percentage of area at risk. Cardiac function was assessed by echocardiography 14 days after infarction. 3. In another series of experiments, rabbits were subjected to 30 min coronary occlusion and 30 min reperfusion and myocardial interstitial 2,3-dihydroxybenzoic acid (DHBA) and 2,5-DHBA levels, indicators of hydroxyl radical, were measured using a microdialysis technique. 4. Infarct size in the edaravone group was significantly reduced compared with that in the control group (27.4 +/- 6.8 vs 43.4 +/- 6.8%, respectively; P < 0.05). The edaravone-induced reduction of infarct size was abolished by pretreatment with L-NAME. Myocardial interstitial levels of 2,3-DHBA and 2,5-DHBA increased 20 and 30 min after ischaemia and peaked at 10 min reperfusion in the control group. Edaravone significantly inhibited the increase in 2,3-DHBA and 2,5-DHBA levels seen during reperfusion. Dihydroethidium staining showing in situ detection of superoxide was less intense in ischaemic myocardium in the edaravone-treated group compared with the control group. Edaravone improved cardiac function and left ventricular remodelling 14 days after infarction. 5. In conclusion, edaravone significantly reduces MI size and improves cardiac function and LV remodelling by decreasing hydroxyl radicals and superoxide in the myocardium and increasing the production of NO during reperfusion in rabbits.     

黄蜀葵总黄酮对全脑缺血损伤的保护作用

目的　研究黄蜀葵总黄酮 (TFA)对脑缺血及再灌注损伤的保护作用。方法　结扎双侧颈总动脉建立小鼠脑缺血模型 ,观察小鼠 6h存活率 ,测定缺血脑组织中丙二醛(MDA)含量 ;采用小鼠氮气缺氧模型 ,观察小鼠存活时间 ;采用结扎双侧颈总动脉合并血压下降法建立兔脑缺血再灌注模型 ,兔脑缺血 60min后再灌注 3 0min ,记录脑缺血和再灌注的脑电图 (EEG) ,测定缺血脑组织的丙二醛 (MDA)、乳酸脱氢酶 (LDH)。结果　TFA(3 0、60、12 0mg·kg-1)延长小鼠缺氧后的存活时间和提高脑缺血后小鼠的存活率及能抑制脑组织中MDA的增高。TFA(12、2 4、48mg·kg-1)抑制兔脑缺血再灌注损伤所致的EEG、MDA、LDH变化。结论　TFA对脑缺血及再灌注损伤有保护作用 ,其机制可能与抗自由基和脂质过氧化有关     

宫内急性缺血及再灌注对胎鼠肾SOD和MDA的影响

目的利用大鼠宫内急性缺血及再灌注模型检测胎龄21d鼠肾损伤后超氧化物歧化酶(SOD)、丙二醛(MDA)的变化,以探讨宫内缺血/再灌注时肾损伤的发病机制。方法选取孕21dWistar大鼠,腹腔麻醉后,暴露双角子宫及供应子宫和卵巢的动静脉血管,钳夹其双角子宫一侧动静脉血管,钳夹时间分别为10、30min,达要求时间后取下动脉夹行再灌注,再灌注时间分别为0.5、2、6、24h,对侧未钳夹宫角内的胎鼠为对照组,每个时间点留取7份标本。分别检测各个时间点胎鼠肾SOD、MDA的含量。结果①SOD活性:缺血10min时SOD活性开始降低(P>0.05),缺血30min时SOD活性下降明显(P<0.05),随再灌注时间的延长,SOD活性逐渐降低,于再灌注6h时达最低(P<0.01),而后SOD活性开始升高,再灌注24h时虽未恢复正常,但与假手术组无差异(P>0.05);缺血10min组与缺血30min组相比,后组明显低于前组,尤为再灌注0.5h和再灌注6h(P<0.01);②MDA含量:缺血10minMDA含量即开始升高(P>0.05),缺血30min时MDA含量升高明显(P<0.05);随再灌注时间的延长,MDA含量逐渐升高,尤为再灌注2、6、24h(P<0.01);缺血10min组与缺血30min组相比,后组明显高于前组,尤为再灌注6h(P<0.01)。结论宫内缺血无再灌注时即有自由基损伤的存在;自由基损伤可能是宫内缺血再灌注肾损伤的发病机制之一。     

Benidipine reduces myocardial infarct size involving reduction of hydroxyl radicals and production of protein kinase C-dependent nitric oxide in rabbits

Japanese white rabbits underwent 30 minutes of ischemia and 48 hours of reperfusion. Benidipine (3 or 10 microg/kg, i.v.) was administered 10 minutes before ischemia with and without pretreatment with L-NAME (10 mg/kg, i.v., a NOS inhibitor), chelerythrine (5 mg/kg, i.v., a PKC blocker) or 5-HD (5 mg/kg, i.v. a mitochondrial KATP channel blocker), genistein (5 mg/kg, i.v. a protein tyrosin kinase blocker). SNAP (2.5 mg/kg/min x 70 minutes, i.v., an NO donor) was also administered 10 minutes before ischemia. Benidipine significantly reduced the infarct size in a dose-dependent manner (3 microg/kg: 29.0 +/- 2.7%, n = 8, 10 microg/kg: 23.0 +/- 2.4%, n = 10) compared with the control (41.6 +/- 3.3%, n = 10). This effect was completely blocked by L-NAME (39.9 +/- 3.6%, n = 8) and chelerythrine (35.5 +/- 2.4%, n = 8) but not by 5-HD (23.0 +/- 2.4%, n = 10) or genistein (24.6 +/- 3.1%, n = 10). SNAP also reduced the infarct size (24.6 +/- 3.1%, n = 8). Benidipine significantly increased the expression of eNOS mRNA at 30 minutes after reperfusion and significantly increased the expression of eNOS protein at 3 hours after reperfusion in the ischemic area of the left ventricle. Benidipine and SNAP significantly decreased myocardial interstitial 2,5-DHBA levels, an indicator of hydroxyl radicals, during ischemia and reperfusion. Benidipine increased myocardial interstitial NOx levels, which effect was blocked by chelerythrine, during 0 to 30 minutes and 150 to 180 minutes after reperfusion. Benidipine reduces the infarct size through PKC-dependent production of nitric oxide and decreasing hydroxyl radicals but not through involving protein tyrosine kinase or mitochondrial KATP channels in rabbits.