褪黑素对海马区神经元的保护作用

为探讨褪黑素对缺血后海马区神经元的保护作用。以 6～ 8月龄沙鼠制成大鼠短暂性脑缺血动物模型 ,腹腔注射褪黑素并以生理盐水作对照 ,用免疫组化法检测术后 2 4h、72h、1 2 0h时海马区bcl-2蛋白的表达。结果 ,注射生理盐水组bcl -2表达在术后 2 4h为 ( 3 .1 6± 0 .1 4 ) %、72h为 ( 1 .78±0 .3 7) %、1 2 0h为 ( 0 .54± 0 .3 6) % ,注射褪黑素组分别为 ( 3 .1 8± 0 .52 ) %、( 2 .95± 0 .2 8) %、( 2 .52±0 .4 3 ) %。术后 72h及 1 2 0h褪黑素组bcl-2显著高于生理盐水组 (P <0 .0 5)。结果提示 ,褪黑素可能有抑制海马神经元凋亡的作用。     

褪黑素对小鼠反复脑缺血再灌注损伤学习记忆的改善作用及机制

目的：研究褪黑素(melatonin，MT)对反复脑缺血再灌注损伤的保护作用及机制。方法：采用清醒小鼠造成反复脑缺血再灌注损伤模型，应用电迷宫法观察小鼠学习记忆情况，比色法、硝酸还原法检测脑组织丙二醛(MDA)、一氧化氮(NO)含量。结果：褪黑素可以明显改善反复脑缺血再灌注小鼠的学习记忆能力，同时可不同程度地抑制脑水肿及由反复脑缺血再灌注引起的脑组织中异常升高的MDA、NO含量。结论：MT对反复脑缺血再灌注损伤有显的保护作用，其机制可能与抑制脑水肿及抑制脑内升高的MDA、NO有关。     

阿司匹林对脑缺血—再灌注时心、肾损伤的保护作用及机制

目的探讨阿司匹林（ASA）对脑缺血－再灌注（CIR）时心、肾损伤的保护作用及机制。方法线拴法制作大鼠局部脑缺血2h、再灌注24h模型,组织病理学观察心、肾损伤程度．生物化学方法测定三磷酸腺苷酶（ATPase）、乳酸脱氢酶（LDH）活性和乳酸（LA）含量,放射免疫法测定血浆前列环素I2（PGI2）和血栓素A2（TXA2）浓度。结果CIR时心肾均呈急性变质性改变,ASA抑制其形态学改变。CIR时,心肾的AT—Pase活性均明显升高,心肌LA含量和LDH下降,肾LDH升高,ASA提高了二器官Ca^2＋ -ATPase活性,维持LDH于正常水平。结论阿司匹林对脑缺血-再灌注时心、肾损伤有明显保护作用。其机制可能与改善心肾组织代谢和维持器官灌流有关。     

紫杉醇对脑缺血-再灌注诱导海马神经元损伤的保护作用

目的研究紫杉醇对脑缺血-再灌注(I-R)后海马神经元损伤的保护作用及分子机制。方法 SD大鼠随机分为假手术对照组(A组)、I-R对照组(B组)、1%DMSO溶剂处理组(C组)、紫杉醇8μg/kg组(D组,缺血前30min脑室注射),每组各10只。采用大鼠四动脉结扎全脑缺血模型,应用免疫印迹法检测紫杉醇对B细胞淋巴瘤-白血病2(Bcl-2)、半胱天冬氨酸蛋白酶3(Caspase-3)表达的影响。结果与A组相比,B、C组Bcl-2及Caspase-3磷酸化表达增加(P<0.05),而D组Bcl-2及Caspase-3磷酸化表达较B组明显减少(P<0.05)。结论紫杉醇可能对脑I-R诱导海马神经元的损伤有保护作用;这种保护作用可能与Bcl-2、Caspase-3蛋白活性密切相关。     

褪黑素对沙土鼠脑缺血再灌注损伤的保护作用

目的研究褪黑素(melatonin,MT)对沙土鼠脑缺血再灌注损伤的神经保护作用。方法用沙土鼠双侧颈总动脉结扎法建立全脑缺血再灌注损伤模型。用开场迷宫测试沙土鼠的定向运动活性的变化。用T迷宫测试沙土鼠的学习及工作记忆能力。光镜下观察缺血后d 7海马CA1区神经元组织形态学变化。结果缺血模型组沙土鼠定向运动活性较假手术组显著增高,学习及工作记忆能力降低。MT可降低沙土鼠的定向运动活性,提高沙土鼠的工作记忆能力;还可显著减轻海马CA1区锥体神经元的病理改变,且作用呈剂量依赖性。结论MT对沙土鼠全脑缺血再灌注损伤有保护作用。     

川芎、冰片配伍对脑缺血大鼠海马和下丘脑神经元的保护作用

目的研究川芎、冰片配伍对全脑缺血大鼠海马和下丘脑神经元的保护机制。方法将全脑缺血大鼠分为假手术组、模型组、川芎组(1.0 g·kg~(-1))、冰片组(0.16 g·kg~(-1))、川芎+冰片组。利用GC-MS方法检测海马/下丘脑的透析液中谷氨酸(glutamate,Glu)、甘氨酸(glycine,Gly)和γ-氨基丁酸(γ-aminobutyric acid,GABA)含量;激光共聚焦技术检测脑片中钙离子含量;TUNEL和电镜技术检测这两个脑区凋亡百分率和超微结构。结果川芎和冰片单用均可减少钙超载,缓解超微结构的改变,联合应用效果更佳。另外,川芎单用可减少两脑区的神经元凋亡指数、升高GABA。冰片仅降低两脑区的Glu,而它们的配伍还可进一步升高下丘脑Gly含量,也表现较好的协同关系。结论川芎和冰片配伍在缓解神经元兴奋毒、钙超载和超微结构异常方面具有较好的协同效应,但抗凋亡方面未见明显协同。     

褪黑素保护肝脏缺血再灌注损伤的实验研究

目的应用大鼠肝缺血再灌注模型,通过分组对照研究,探讨褪黑素(MT)对肝脏缺血再灌注损伤(IRI)的保护作用及相关机理.方法建立SD大鼠肝缺血再灌注模型,64只大鼠随机分为2组:对照组n=32只:缺血前1h经尾静脉注入生理盐水1ml;MT用药组,n=32只:缺血前70min、缺血前35min、再灌注初期、再灌注1h以及再灌注2h分别向腹腔注射MT10mg/kg.测定两组缺血前、缺血35min末、再灌注2h和再灌注4h血清丙氨酸基转氨酶(ALT)、乳酸脱氢酶(LDH)、肿瘤坏死因子-α(TNF-α)、肝组织匀浆丙二醛(MDA)、超氧化物歧化酶(SOD)、一氧化氮(NO)、内皮素-1(ET-1);免疫组化测定缺血前、再灌注4h肝组织诱导型一氧化氮合成酶(iNOs)的表达.结果①血清学检查:MT组再灌注2h、4h血清ALT、LDH与对照组相比显著降低(P＜0.01),MT组再灌注2h、4h TNF-α与对照组相比显著降低(P＜0.01).②肝组织匀浆:MT组缺血35min末MDA与缺血前相比显著降低(P＜0.01),MT组再灌注2h、4h MDA与对照组相比显著降低(P＜0.01);MT组再灌注2h、4h与对照组相比NO显著降低(P＜0.01);MT组缺血35min末、再灌注2h、再灌注4h与对照组相比ET-1显著降低(P＜0.01);③免疫组化:MT组iNOs蛋白表达显著低于对照组.结论 MT能够明显减轻急性期肝脏IRI,其作用机理可能通过减少氧自由基和TNF-α的释放,抑制iNOs表达,从而减少NO和ET-1的产生.     

L-精氨酸对心肌缺血再灌注的影响

目的 :寻找一种临床心脏外科手术中更好的心肌保护方法。方法 :中国长耳白兔 2 4只 ,随机分为 3组 :对照组、含血停跳液组、L 精氨酸组。采用Langendorff离体兔心灌注模型 ,操作模拟临床心脏手术过程。检测指标 :冠脉流出液中肌酸激酶同工酶 (CK MB)和乳酸脱氢酶 (LDH)漏出速率、心肌含水量、心肌丙二醛含量、心肌超氧化物歧化酶 (SOD)活性、心肌髓过氧化物酶 (MPO)活性、心肌组织超微结构。结果 :与含血停跳液组相比 ,L 精氨酸组乳酸脱氢酶漏出速率、肌酸激酶同功酶漏出速率、心肌含水量、心肌MDA含量、MPO活性明显降低 ,SOD活性偏高(P <0 0 1)。L 精氨酸组心肌超微结构损害明显减轻。结论 :心停跳液中加入NO前体L 精氨酸明显减轻心肌缺血再灌注损伤 ,有利于心肌保护     

褪黑素对神经元和胶质细胞低糖低氧损伤不同时期的影响

目的　通过观察褪黑素对神经元和胶质细胞低糖低氧损伤不同时期的影响 ,进一步探讨分析褪黑素对神经细胞低糖低氧损伤保护作用的机制。方法　体外培养神经细胞和胶质细胞 ,建立低糖低氧急性损伤模型和低糖低氧再灌注后慢性损伤模型 ,通过MTT比色 ,测定培养液中LDH活性和NO、MDA的含量 ,观察褪黑素对神经细胞和胶质细胞的保护作用。结果　 10 -6、10 -7、10 -8mol·L-1的褪黑素均能降低低糖低氧损伤所致的神经细胞培养液中MDA含量的升高 ,但 10 -6、10 -7mol·L-1的褪黑素却升高其NO水平。10 -6、10 -7、10 -8mol·L-1的褪黑素能够使在低糖低氧损伤急性期混合培养的神经细胞和胶质细胞LDH释放增多 ,MTT比色分析的A570 值下降增多 ;而在低糖低氧再灌注后慢性损伤期 ,褪黑素可抑制LDH的释放 ,提高MTT比色分析的A570 值。结论　①褪黑素降低神经细胞培养液中的MDA含量 ,升高NO的含量 ,这可能是褪黑素保护神经元所受低糖低氧损伤众多机制之一。②在低糖低氧急性损伤期 ,褪黑素不利于神经元和胶质细胞的存活 ,而在低糖低氧再灌注后慢性损伤期 ,褪黑素可对神经元和胶质细胞产生明显保护作用。     

Effect of melatonin on altered expression of vasoregulatory genes during hepatic ischemia/reperfusion

The production of reactive oxygen species during hepatic ischemia/reperfusion (I/R) can help create disturbances in microcirculation. This study examined the effect of melatonin, a pineal secretory product and a potent antioxidant, on the expression of vascular stress genes during hepatic I/R. Rats were subjected to 60 min of hepatic warm ischemia followed by 5 h reperfusion. Melatonin (10 mg/kg) was administered intraperitoneally 15 min before ischemia and immediately before reperfusion. The serum alanine aminotransferase and hepatic malondialdehyde levels increased markedly after I/R. These increases were significantly inhibited by melatonin. The levels of endothelin-1 (ET-1) and its receptor, ET(B) mRNA, were elevated by I/R but attenuated by melatonin. The mRNA levels of endothelial nitric oxide synthase (eNOS), inducible nitric oxide synthase (iNOS), and heme oxygenase-1 were significantly higher after I/ R. Melatonin augmented the increase in the eNOS mRNA level, whereas it reduced the increase in the iNOS mRNA level. The expression of tumor necrosis factor-alpha was increased markedly by I/R. This increase was also attenuated by melatonin. These results suggest that melatonin ameliorates the imbalanced expression of the vascular stress genes during hepatic I/R through its antioxidant property.     

The effects of melatonin on electrical field stimulation-evoked biphasic twitch responses in the ipsilateral and contralateral rat vasa deferentia after unilateral testicular torsion/detorsion

It is not known whether there is an impairment in vas deferens motility after unilateral testicular torsion/detorsion. Therefore, we aimed to determine whether the electrical field stimulation (EFS)-evoked biphasic contractions are altered in ipsilateral and contralateral rat vasa deferentia obtained from animals exposed to the unilateral testicular torsion/detorsion procedure. We also evaluated the effects of melatonin (MLT), which is a strong antioxidant, on these contractile responses. Rats were subjected to torsion of the left testis for 2 h and then detorsion was performed. Contractility studies were carried out 2 h or 24 h after detorsion. Vas deferens strips were prepared from both the ipsilateral and the contralateral site 2 h or 24 h after the detorsion procedure to record EFS-evoked biphasic twitch responses. The same experimental protocol was repeated for the MLT-treated rats. Both phases of EFS-evoked contractions were decreased after torsion/detorsion in the ipsilateral vas deferens. MLT treatment increased torsion/detorsion-induced reduction of both phases of contractions after 2 h and 24 h. In the contralateral vas deferens, the first phase of EFS-evoked contractions was not changed, while the second phase of contractions was diminished 2 h and 24 h after detorsion. Although MLT decreased the second phase of contractions 2 h and 24 h after detorsion, it reduced the first phase of contractions only 2 h after detorsion. These results suggest that MLT produces an inhibition on EFS-evoked biphasic twitch responses in the ipsilateral and contralateral rat vasa deferentia following unilateral testicular torsion/detorsion in the rat.     

非拉尼特对大鼠缺血-再灌注心肌的保护作用

目的 探讨阿魏酸硝酸酯类药物非拉尼特（FLNT）对大鼠缺血-再灌注心肌的保护作用及其机制。方法采用大鼠在体缺血-再灌注模型，将动物随机分为6组。假手术组（对冠脉只穿线不结扎）；模型对照组（给予等剂量的0.5%羧甲基纤维素钠溶液）；FLNT低、中、高剂量药物组（分别给予FLNT 2，4，8 mg·kg^-1）；阳性对照组（给予硝酸甘油 2 mg·kg^-1）。大鼠进行缺血40 min，再灌注3 h后测定心肌梗死范围、心肌组织及血清学指标，并定时记录心电图。结果FLNT组心肌梗死面积、血清肌酸激酶和乳酸脱氢酶活性明显减少（P＜0.05），心肌组织中一氧化氮（NO）含量和超氧化物歧化酶（SOD）活性显著增加, 丙二醛含量显著下降（P＜0.05）。能显著地阻止T波的升高（P＜0.05）和R波的降低（P＜0.05），降低病理性Q波的产生。结论FLNT对大鼠缺血 再灌注心肌有保护作用，其机制与NO升高以及机体的抗氧化能力增强有关.     

Protective effect of nitric oxide on ischemia/reperfusion-induced renal injury and endothelin-1 overproduction

To elucidate the role of nitric oxide (NO) in the pathogenesis of ischemic acute renal failure, we examined the effects of (+/-)-(E)-4-ethyl-2-[(E)-hydroxyimino]-5-nitro-3-hexenamide (FK409) and N(G)-nitro-L-arginine methyl ester (L-NAME) as a NO donor and a non-selective NO synthase inhibitor on ischemia/reperfusion-induced renal injury and renal endothelin-1 content. Ischemic acute renal failure was induced by occlusion of the left renal artery and vein for 45 min followed by reperfusion, 2 weeks after contralateral nephrectomy. At 24 h after reperfusion, renal function in untreated acute renal failure rats markedly decreased and histological examination revealed severe renal damage. In addition, increases in renal endothelin-1 contents were evident in the acute renal failure rats at 2, 6, and 24 h after reperfusion, respectively. Pretreatment with FK409 (1 or 3 mg/kg, i.v.) attenuated ischemia/reperfusion-induced renal dysfunction, histological damage, and endothelin-1 overproduction after reperfusion. In contrast, pretreatment with L-NAME (1 or 10 mg/kg, i.v.) aggravated renal injuries of acute renal failure rats at 24 h after reperfusion, and the effect is accompanied by further increases in the renal endothelin-1 content at 2 and 6 h, but not at 24 h, after reperfusion. These results suggest that suppressive effects of NO on the renal endothelin-1 overproduction induced by ischemia/reperfusion in an early phase are probably responsible for the protective effect of NO against ischemic acute renal failure.     

人参皂苷Rg1对脑缺血再灌注大鼠nNOS，iNOS表达的影响

【摘要】 目的 探讨人参皂苷Rg1对脑缺血再灌注大鼠脑组织一氧化氮合酶（NOS）表达的影响。方法 将大鼠随机分成假手术组,模型组（脑缺血再灌注损伤组）,人参皂苷Rg1 10,20,40mg/kg组,尼莫地平组（阳性药物对照组）,每组10只。采用大鼠中动脉栓塞法制作大鼠脑缺血再灌注模型,观察大鼠再灌注后神经功能缺损情况,采用比色法检测大鼠nNOS,iNOS和一氧化氮（NO）的含量,应用免疫组化和免疫印迹法检测脑组织缺血再灌注后nNOS,iNOS的表达。结果 （1）人参皂苷Rg1各组大鼠脑缺血后神经功能评分明显低于模型组（p<0.05）;（2）与模型组相比,人参皂苷Rg1各组随浓度增高nNOS含量及表达增高（p<0.05）,iNOS含量及表达明显降低（p<0.05）;（3）免疫组化和免疫印迹的结果也证明这一趋势。结论 人参皂苷Rg1防治大鼠脑缺血再灌注损伤的机制可能与激活nNOS,抑制iNOS有关,且以高剂量效果较好。     

三七皂苷对氧化低密度脂蛋白损伤血管内皮细胞保护作用的研究

目的:研究三七皂苷(PNS)对氧化低密度脂蛋白(Ox-LDL)损伤血管内皮细胞的保护作用。方法:体外培养人脐静脉内皮细胞(HUVEC),加入100mg·L-1Ox-LDL造成细胞损伤,同时加入不同浓度PNS进行干预。观察形态学变化;采用MTT法测定细胞活性;比色法检测细胞上清液中乳酸脱氢酶(LDH)的释放量;硝酸还原法和放射免疫法分别测定HUVEC培养上清液中一氧化氮(NO)、内皮素(ET)含量。结果:各剂量PNS可使作用Ox-LDL的HUVEC形态趋于正常。与正常对照组比较,HU-VEC经Ox-LDL作用后,细胞活性显著下降,LDH的释放量显著升高;300、100、30mg·L-1PNS显著升高细胞活性,抑制LDH释放。HUVEC经Ox-LDL作用后,与正常对照组比较,培养上清液中NO含量显著降低,ET含量显著升高;300、100mg·L-1PNS显著升高NO含量,300mg·L-1PNS显著降低ET含量。结论:PNS对Ox-LDL损伤的血管内皮细胞具有一定的保护作用,可调节内皮细胞活性物质NO、ET的分泌。     

葱白提取物对心肌缺血-再灌注损伤大鼠的保护作用及其机制

目的探讨葱白提取物(FOB)预处理对大鼠心肌缺血-再灌注(I/R)损伤的保护作用及其机制。方法SD成年大鼠随机分为假手术组,I/R组,FOB(小、中、大剂量)(300,600,1200 mg·kg^-1)+I/R组和硝酸甘油+I/R组,每组10只;结扎左冠状动脉前降支30 min再灌注24 h建立在体心肌I/R损伤模型。多导生理记录仪记录和分析左心室功能变化;酶联免疫吸附测定(ELISA)法检测大鼠血清肌酸激酶(CK)、乳酸脱氢酶(LDH)和肌酸激酶同工酶(CK-MB)水平;Western blotting和实时-聚合酶链反应(RT-PCR)检测心肌Bax和Bcl-2蛋白及mRNA表达水平;免疫荧光检测细胞色素C(Cyt-C)和凋亡酶激活因子1(Apaf-1)的表达。结果与I/R组比较,FOB(小、中、大剂量)+I/R组大鼠心功能均明显改善;CK、LDH和CK-MB浓度降低;Bax蛋白及mRNA表达水平下调,同时Bcl-2蛋白及mRNA表达水平升高;Cyt-C及Apaf-1蛋白表达下降(P<0.05),并存在一定量效关系。结论FOB具有显著改善大鼠心肌I/R损伤及拮抗心肌细胞凋亡的作用,其机制与调节心肌Bax、Bcl-2、Cyt-C和Apaf-1的表达密切相关。     

川芎嗪对大鼠肾缺血-再灌注后核因子-kB表达与一氧化氮合酶活性的影响

目的 研究川芎嗪对肾脏缺血-再灌注后肾功能、核因子-κB(NFκB)的表达及一氧化氮合酶(NOS)活性的影响.方法 将30只SD大鼠随机分为假手术组、缺血-再灌注模型组和川芎嗪处理组,化学法检测血清肌酐(Cr)和尿素氮(BUN)浓度以及左肾组织中一氧化氮合酶活性,HE染色后镜下观察肾脏病理变化,免疫组化测定肾组织NF-KB的表达水平.结果 川芎嗪15,30,45 mg·kg-1剂量于缺血前静脉注射均能降低再灌注时肾脏组织中NF-κB的表达.抑制诱生型NOS(iNOS)活性、降低尿素氮和肌酐水平,其中以15 mg·kg-1作用最为显著.结论 川芎嗪15,30,45mg·kg-1剂量均能减轻肾缺血损伤,其机制可能与抑制NF-κB的表达、降低iNOS活性有关,且该作用与川芎嗪的剂量相关,以15 mg·kg-1剂量的效果最好.     

The Effects of Ischemic Postconditioning on Myocardial Function and Nitric Oxide Metabolites Following Ischemia-Reperfusion in Hyperthyroid Rats

Ischemic postconditioning (IPost) could decrease ischemia-reperfusion (IR) injury. It has not yet reported whether IPost is useful when ischemic heart disease is accompanied with co-morbidities like hyperthyroidism. The aim of this study was to examine the effect of IPost on myocardial IR injury in hyperthyroid male rats. Hyperthyroidism was induced with administration of thyroxine in drinking water (12 mg/L) over a period of 21 days. After thoracotomy, the hearts of control and hyperthyroid rats were perfused in the Langendorff apparatus and subjected to 30 minutes global ischemia, followed by 120 minutes reperfusion; IPost, intermittent early reperfusion, was induced instantly following ischemia. In control rats, IPost significantly improved the left ventricular developed pressure (LVDP) and ±dp/dt during reperfusion (p<0.05); however it had no effect in hyperthyroid rats. In addition, hyperthyroidism significantly increased basal NO_x (nitrate+nitrite) content in serum (125.5±5.4 µmol/L vs. 102.8±3.7 µmol/L; p< 0.05) and heart (34.9±4.1 µmol/L vs. 19.9±1.94 µmol/L; p<0.05). In hyperthyroid groups, heart NO_x concentration significantly increased after IR and IPost, whereas in the control groups, heart NO_x were significantly higher after IR and lower after IPost (p< 0.05). IPost reduced infarct size (p<0.05) only in control groups. In hyperthyroid group subjected to IPost, aminoguanidine, an inducible nitric oxide (NO) inhibitor, significantly reduced both the infarct size and heart NO_x concentrations. In conclusion, unlike normal rats, IPost cycles following reperfusion does not provide cardioprotection against IR injury in hyperthyroid rats; an effect that may be due to NO overproduction because it is restored by iNOS inhibition.