地西泮对大鼠脑缺血-再灌注损伤的保护作用

目的 观察地西泮对全脑缺血—再灌注损伤的保护作用。方法 采用改良的Pulsinelli四血管法建立大鼠全脑缺血模型，缺血时间为15min。动物随机分为四组：假手术组、缺血—再灌注组、地西泮治疗组和地西洋预注组。于动物存活第6天行Y—型迷宫检测大鼠的学习能力，第7天检测记忆能力并行海马CAl区组织病理学检查。结果 大鼠缺血—再灌注后学习和记忆能力明显下降，海马CAl区神经元细胞损伤，地西泮治疗组与地西泮预注组能不同程度减轻海马CAl区神经元的损伤，改善缺血—再灌注后学习和记忆的降碍。结论 一过性脑缺血能产生神经元损伤。地西泮对全脑缺血—再灌注有一定的保护和治疗作用。     

氨基氧乙酸对大鼠局灶性脑缺血损伤的影响

目的 评价氨基氧乙酸对大鼠局灶性脑缺血损伤的影响.方法 健康雄性SD大鼠80只,体重250～280 g,月龄2.5个月,采用随机数字表法,将其随机分为5组(n＝16):假手术组(S组)、脑缺血组(Ⅰ组)、低、中、高剂量氨基氧乙酸组(AL组、AM组和AH组).Ⅰ组、AL组、AM组和AH组采用线栓法(阻塞大脑中动脉)制备大鼠局灶性脑缺血损伤模型.AL组、AM组和AH组于缺血3h时分别腹腔注射氨基氧乙酸25、50、100 μmol/kg,S组和Ⅰ组给予等容量生理盐水1ml/kg.每组于给予氨基氧乙酸后21 h时取8只大鼠,进行神经功能缺陷评分,然后处死大鼠,取脑组织,分离皮层、海马、纹状体,测定胱硫醚-β合酶( CBS)活性.每组于给予氨基氧乙酸后21 h时处死另外8只大鼠,取脑组织,测定脑梗死体积.结果 与S组比较,Ⅰ组神经功能缺陷评分、皮层和海马CBS活性升高,脑梗死体积扩大(P<0.05),纹状体CBS活性差异无统计学意义(P＞0.05);与Ⅰ组比较,AM组和AH组神经功能缺陷评分、皮层和海马CBS活性降低,脑梗死体积缩小,纹状体CBS活性差异无统计学意义(P＞0.05);AL组上述指标差异无统计学意义(P＞0.05).结论 氨基氧乙酸可减轻大鼠局灶性脑缺血损伤,其机制与抑制CBS活性,减少H2S生成有关.     

大鼠脑缺血损伤后锂盐治疗对海马CA1区的影响

目的探讨大鼠局灶脑缺血损伤后锂盐治疗对海马CA1神经元形态学变化的影响。方法将SD大鼠随机分为假手术组(SH组)、缺血-再灌注组(IR组)和缺血损伤后氯化锂治疗组(LI组),按处死时间不同,将各组再分为三个亚组:SH1d、SH2d、SH3d组;IR1dI、R2dI、R3d组;LI1d、LI2d、LI3d组。线栓法制作大鼠大脑中动脉闭塞(MCAO)局灶脑缺血模型,1.5 h后再灌注。LI组于脑缺血后1 h,氯化锂(3 mmol/kg)腹腔注射,每天一次至处死。SH组和IR组以生理盐水替代。HE染色比较各组缺血损伤后1、2、3 d海马CA1区神经元损伤程度。结果虽然LI组与IR组的CA1区存活锥体细胞数存在类似下降趋势,但LI2d组、LI3d组分别较IR2d组I、R3d组存活锥体细胞数明显增多(P<0.01)。结论大鼠局灶脑缺血后氯化锂的治疗能减轻海马神经元的损伤程度。     

Relationship between blood viscosity and cerebral ischemia after surgical treatment of ruptured intracranial aneurysms

To determine the role of blood viscosity after surgical treatment of ruptured intracranial aneurysms, the relationship between blood viscosity and clinical condition was examined in 17 patients. A total of 213 blood samples were analyzed. An inverse correlation was found between blood viscosity and level of consciousness; in addition, blood viscosity was higher when focal neurologic deficit was observed. Hematocrit was similarly related to clinical condition, although the correlations observed were less strong. Postoperative plasma viscosity was higher in patients with focal neurologic deficit. Regular blood viscosity measurements are of value in patients at risk for developing cerebral ischemia.     

氨基胍对局灶性脑缺血诱导大鼠脑神经元凋亡的影响

目的观察选择性诱导型一氧化氮合酶抑制剂氨基胍(AG)对局灶性脑缺血诱导大鼠脑神经元凋亡的影响,探讨AG对脑缺血大鼠脑神经元的保护作用及其机制。方法健康雄性SD大鼠54只,体重250-300 g,随机分为3组:假手术组(SH组)、缺血组(IS组)、AG治疗组(AG组),每组18只。每组按给药时机分为3个亚组:缺血2 h组、缺血6 h组、缺血12 h组,每亚组6只。IS、AG组采用插线法制备大鼠大脑中动脉阻断模型。AG组每次腹腔注射AG 100 mg/kg,每日2次,连续3 d。IS 组给予等量的生理盐水。治疗后大鼠断头取脑,采用流式细胞仪测定脑组织神经元凋亡率、Bcl-2蛋白、Bax蛋白表达及Bcl-2蛋白与Bax蛋白比值(Bcl-2/Bax)。结果与SH组比较,IS、AG组各亚组神经元凋亡率及Bax蛋白表达升高,AG组各亚组Bcl-2蛋白表达升高,IS、AG组各亚组Bcl-2/Bax降低(P <0.01);与IS组比较,AG组各亚组神经元凋亡率降低,AG组各亚组Bcl-2蛋白表达及Bcl-2/Bax升高,AG组Bax蛋白表达降低(P<0.05或0.01)。结论AG通过增加Bcl-2蛋白表达,降低Bax蛋白表达,调节Bcl-2/Bax平衡,对脑缺血大鼠脑神经元产生一定程度的保护作用。     

L-精氨酸对局灶性脑缺血大鼠神经元凋亡的影响

目的 评价L-精氨酸(L-arg)对局灶性脑缺血大鼠神经元凋亡的影响.方法 健康雄性SD大鼠56只,体重250～300 g,随机分为7组(n=8):假手术组(SH组)、脑缺血2 h组(Is1组)、脑缺血2 h L-arg治疗组(L-arg1组)、脑缺血6 h组(IS2组)、脑缺血6 h L-arg治疗组(L-arg2组)、脑缺血12h组(IS3组)及脑缺血12 h L-arg治疗组(L-arg3组).采用线栓法制备大鼠大脑中动脉阻塞模型.各L-arg治疗组分别于脑缺血后腹腔注射L-精氨酸500 mg/kg,2次/d,治疗3 d;IS组给予等容量生理盐水.治疗3 d后取脑,测定缺血区域神经元凋亡率、Caspase-3蛋白、Bcl-2蛋白和Bax蛋白的表达水平.结果 与SH组比较,IS1组、IS2组和IS3组神经元凋亡率升高,Caspase-3蛋白和Bax蛋白表达上调,Bcl-2/Bax蛋白比值降低(P＜0.01);与IS1组和IS2组比较,L-arg1组和L-arg2组神经元凋亡率降低,Caspase-3蛋白和Bax蛋白表达下调,Bcl-2蛋白表达上调,Bcl-2/Bax蛋白比值升高(P＜0.01).IS3组与L-arg3组上述指标差异无统计学意义(P＞0.05).结论 L-arg可减少脑缺血早期大鼠神经元凋亡,具有一定的治疗作用,其机制可能与下调Caspase-3蛋白表达、调节Bcl-2/Bax蛋白平衡有关.     

Low-density lipoprotein apheresis: clinical results with different methods

In 40 patients (22 women, 18 men) suffering from familial hypercholesterolemia resistant to diet and lipid lowering drugs, low-density lipoprotein (LDL) apheresis was performed over 84.9 +/- 43.2 months. Four different systems (Liposorber, 28 of 40, Kaneka, Osaka, Japan; Therasorb, 6 of 40, Baxter, Munich, Germany; Lipopak, 2 of 40, Pocard, Moscow, Russia; and Dali, 4 of 40, Fresenius, St. Wendel, Germany) were used. With all methods, average reductions of 50.6% for total cholesterol, 52.2% for LDL, 64.3% for lipoprotein (a) (Lp[a]), and 43.1% for triglycerides, and an average increase of 10.3% for high-density lipoprotein (HDL) were reached. Severe side effects such as shock or allergic reactions were very rare (0.5%) in all methods. In the course of treatment, an improvement in general well being and increased performance were experienced by 39 of 40 patients. Assessing the different apheresis systems used, at the end of the trial, there were no significant differences with respect to the clinical outcome experienced with the patients' total cholesterol, LDL, HDL, and triglyceride concentrations. However, to reduce high Lp(a) levels, the immunoadsorption method with special Lp(a) columns (Lipopak) seems to be most effective: -59% versus -25% (Kaneka) - (Baxter), and -29% (Dali). The present data demonstrate that treatment with LDL apheresis of patients suffering from familial hypercholesterolemia resistant to maximum conservative therapy is very effective and safe even in long-term application.     

探讨脑缺血大鼠骨髓基质细胞移植后减少神经细胞凋亡的作用

目的探讨大鼠局灶性脑缺血后骨髓基质细胞移植对神经细胞凋亡及相关蛋白表达的影响。方法取大鼠股骨髓基质细胞,分化培养为骨髓基质细胞源神经干细胞。将32只健康SD大鼠随机平均分为4组。A组不建立局灶性脑缺血模型,不做任何移植,其余步骤同其他组。B、C、D组均建立局灶性脑缺血再灌注模型。B组将1mlPBS经尾静脉注入大鼠体内;C组将1ml3×106个骨髓基质细胞经尾静脉注入大鼠体内;D组将1ml3×106个骨髓基质细胞源神经干细胞经尾静脉注入大鼠体内。分别在移植后7d和14d行脑灌注固定取材,应用免疫组织化学染色检测脑组织中Bcl2、Bax蛋白表达阳性的细胞,原位末端脱氧核糖核酸转移酶标记法(TUNEL)检测神经细胞凋亡数。结果C组和D组各时点的神经细胞凋亡数均少于B组(P<0.01),C组和D组移植14d时,神经细胞凋亡数显著少于移植7d时(P<0.01),移植14d时D组神经细胞凋亡数显著少于C组(P<0.05)。C组和D组Bcl2表达阳性的细胞数显著高于B组(P<0.01)。C组和D组Bax蛋白表达阳性的细胞数明显低于B组(P<0.01)。结论骨髓基质细胞源神经干细胞可能通过上调Bcl2蛋白,下调Bax蛋白的表达,减少神经细胞凋亡,从而对脑缺血再灌注损伤后的神经细胞起保护作用。     

急性心肌梗死急诊介入治疗后血清铁蛋白、超敏C反应蛋白、肌钙蛋白、脑钠肽及低密度脂蛋白的变化及意义

目的 探讨血清铁蛋白(serum ferritin,SF)、超敏C反应蛋白(high sensitive C-reactive protein,hsCRP)、肌钙蛋白T(troponin T,TnT)、脑钠肽(B-type natriuretic peptide,BNP)及低密度脂蛋白(low densith lipoprotein,LDL)与急性心肌缺血/再灌注损伤(myocardial ischemia/reperfusion injury,MURI)的关系. 方法 将急性心肌梗死(acute myocardial infarction,AMI)患者按入院后手术时间分为急诊介入组(60例)和择期手术组(60例),选择同期我院正常体检者作为正常对照组(60例).正常对照组患者于体检当天,急诊介入组、择期手术组分别于入院当天及介入术后24 h收集血样,检测血清中SF、hsCRP、TnT、BNP及LDL水平,并检测ST段回落百分比(ST-segment resolution,sumSTR),进行比较分析. 结果 急诊介入组和择期手术组入院时SF、hsCRP、TnT、BNP均高于正常对照组,LDL水平低于正常对照组,差异有统计学意义(P＜0.05);但急诊介入组与择期手术组比较,差异无统计学意义(P＞0.05).急诊介入组术后24 h SF、hsCRP、TnT、BNP及LDL均高于择期手术组,差异有统计学意义(P＜0.05). 结论 AMI急诊介入术后血清中SF、hsCRP、TnT、BNP及LDL均明显变化,联合这几项指标检测对MI/RI的严重程度评估和预防具有重要的临床意义.     

The effects of nicardipine given after 10-minutes complete global cerebral ischemia on neurologic recovery in dogs

The effect of nicardipine (NC) on neurologic recovery from ischemic insult after 10-minutes complete global cerebral ischemia was evaluated in dogs by examination of neurologic recovery score (NRS: complete recovery = 100, death = 0). Ischemia was achieved by occlusion of ascending aorta, and NC, 10µg·kg^–1 in bolus followed by infusion of 0.33µg·kg^–1·min^–1 for 2 hours, was administered immediately after re-establishment of circulation. The mortality at 7th day was 2/9 in the control © and 1/9 in the NC group (ns). NRS on 2nd day was 52.3 ± 6.8 in the C and 70.6 ± 6.5 in the NC (P 0.05), but that on 7th day did not differ between the two groups. The numbers of dogs recovered to over 80 in NRS on the 2nd day was 1/9 in the C and 5/9 in the NC (P 0.05), but that on the 7th day increased to 3/9 in the C and remained at 5/9 in the NC (ns). These results suggest that NC accelerates the early neurologic recovery from ischemic damage, but influences little the final outcome.(Iwatsuki N, Ono K, Takahashi M et al.: The effects of Nicardipine given after 10-minutes complete global cerebral ischemia on neurologic recovery in dogs. J Anesth 4: 337–342, 1990)     

Oxidation of lipoprotein in injury and repair of obstructive nephropathy

Background. To test the hypothesis that oxidized low density lipoprotein (oLDL) is involved in the renal injury of obstructive nephropathy, male Sprague-Dawley rats weighing 125–150 g were used. Methods. Three days after arrival, the rats were randomly assigned to undergo: (1) sham operation, (2) left unilateral ureteral obstruction (UUO), or (3) reversal of the unilateral ureteral obstruction (R-UUO). Seven days after the reversal operation or 10 days after the sham or UUO procedure, all animals were killed by exsanguination under anesthesia, with blood taken from the abdominal aorta. LDL was prepared by gradient ultracentrifugation and used immedi-ately after isolation. Rat mesangial cells were utilized with an LDL concentration of 100 μg/ml/protein in the media. After 72 h, cell survival was determined by the 3-(4,5-dimethylthiazol-2-yl)-2,5 diphenyltetrazolium bromide (MTT) method. Cell survival was determined by comparing the optical density between the control wells and the experimental wells. In order to investigate the mechanisms of injury and repair of obstructive nephropathy, data for kidney apoptosis, malondialdehyde (MDA), and transforming growth factor β1 (TGFβ1) mRNA were obtained in the sham-operated, UUO, and R-UUO groups. Results. Our results showed that LDL malondialdehyde during UUO was increased 87% over baseline values (P < 0.005). With R-UUO, the oxidized LDL dropped 23% from the peak values during UUO (P < 0.005), but was still different from that of the baseline values (P < 0.025). Rat mesangial cell survival, after 72 h exposure to oLDL, inversely correlated to oLDL cytotoxicity and showed a 14% drop during UUO compared with sham-operated animals (P < 0.01). Cell survival increased 11% after R-UUO (P < 0.02) and was not different from control values (P = NS). The apoptotic counts by the TUNEL (terminal deoxynucleotidyl transferase-mediated deoxyuridine triphosphate nick end-labelling) technique showed significant increases during UUO and a noticeable reduction after R-UUO. Conclusion. Our data support the proposition that UUO stimulates oxidation of LDL. The cytotoxicity of oLDL plays a significant role in the injury of UUO. A decrease in cytotoxicity was associated with the repair in R-UUO. Our observations that apoptosis follows this same pattern, point to the importance of apoptosis in the injury and repair of obstructive nephropathy. Future studies to interrupt these processes of injury may lead to novel treatment modalities in reversing the injury and hastening the repair of obstructive nephropathy. Received: January 26, 1999 / Accepted: April 23, 1999     

Characteristics of low‐density and high‐density lipoprotein subclasses in pediatric renal transplant recipients

Renal transplant recipients often suffer from dyslipidemia which is one of the principal risk factors for cardiovascular disease. This study sought to determine characteristics of high‐density lipoprotein (HDL) and low‐density lipoprotein (LDL) particles and their associations with carotid intima‐media thickness (cIMT) in a group of pediatric renal transplant recipients. We also examined the influence of immunosuppressive therapy on measured LDL and HDL particle characteristics. HDL size and subclass distribution were determined using gradient gel electrophoresis, while concentrations of small, dense LDL (sdLDL)‐cholesterol (sdLDL‐C) and sdLDL‐apolipoprotein B (sdLDL‐apoB) using heparin‐magnesium precipitation method in 21 renal transplant recipients and 32 controls. Renal transplant recipients had less HDL 2b (P < 0.001), but more HDL 3a (P < 0.01) and 3b (P < 0.001) subclasses. They also had increased sdLDL‐C (P < 0.01) and sdLDL‐apoB (P < 0.05) levels. The proportion of the HDL 3b subclasses was a significant predictor of increased cIMT (P < 0.05). Patients treated with cyclosporine had significantly higher sdLDL‐C and sdLDL‐apoB concentrations (P < 0.05) when compared with those on tacrolimus therapy. Pediatric renal transplant recipients have impaired distribution of HDL and LDL particles. Changes in the proportion of small‐sized HDL particles are significantly associated with cIMT. Advanced lipid testing might be useful in evaluating the effects of immunosuppressive therapy.     

脐血间充质干细胞移植对大鼠局灶性脑缺血的影响

目的　从人脐血中分离纯化间充质干细胞(MSC) ,观察其移植对大鼠大脑中动脉栓塞后神经功能恢复的影响及细胞的存活、迁移向神经细胞分化的情况。方法　雄性SD大鼠45只,用线栓法建立大鼠大脑中动脉栓塞(MCAO)模型,大鼠随机分为3组:MSC移植组、单核细胞组和生理盐水组。移植后1、7、14、2 1、2 8d采用改良神经功能损害评分(mNSS)观察大鼠神经功能恢复情况,应用免疫组织化学和免疫荧光双标记技术检测5溴 2脱氧尿核苷(BrdU )标记的MSC细胞的存活、迁移及其胶质纤维酸性蛋白(GFAP)和神经元特异性核蛋白(NeuN)的表达。结果　人脐血MSC细胞移植可显著提高大鼠局灶性脑缺血后神经功能的恢复(P <0 .0 5 )。移植的MSC细胞可在大鼠脑组织中存活,并向缺血区域迁移,11.67%MSC细胞表达GFAP ,3 .72 %MSC细胞表达NeuN。结论　人脐血中含有MSC细胞并可促进局灶性脑缺血大鼠的神经功能恢复,移植细胞可在大鼠脑缺血区域中存活、迁移并向星形胶质细胞或神经元分化     

Selective hemapheresis, an effective new approach in the therapeutic management of disorders associated with rheological impairment: mode of action and possible clinical indications

The in vitro measurement of whole-blood viscosity, plasma viscosity, and erythrocyte aggregability is easy to perform, but they only allow a partial insight into the complexity of blood flow characteristics; however, they permit definition of the rheological properties of new hemorheological therapeutic modalities such as extracorporeal plasma therapy as described in this paper. Under more theoretical aspects, it becomes obvious that such hemorheological approaches should either improve the vasomotoric properties of blood vessels, reduce the circulating red blood cell concentration, or improve the viscosity by reducing the concentration of hemorheologically relevant plasma proteins. In this review, the rheological effect of a single apheresis treatment with different devices was compared. Due to their differences in selectivity, the extracorporeal methods have different effects on the rheologically relevant plasma proteins, and, therefore, their rheological effectiveness differs remarkably. Today, the classical blood letting and plasma exchange treatment have been replaced by erythrapheresis and selective devices for extracorporeal plasma treatment, respectively. For more than 10 years, the following 5 more-or-less selective apheresis procedures are commercially available: immunoadsorption, differential filtration, polyanion adsorption by dextrane sulfate as well as by polyacrylate, and polyanion precipitation by heparin as polyanion. The last three procedures are semiselective and, therefore, relatively unspecific whereas immunoadsorption only affects the plasma lipoprotein concentration. Several studies have shown the effective use of extracorporeal hemorheotherapy for the treatment of various diseases including macro- and cryoglobulinemia, Raynaud's disease, hyperlipoproteinemia (often characterized by premature atherosclerosis and coronary heart disease and peripheral arterial occlusive disease), cerebral multi-infarct demention and acute ischemic stroke, sudden hearing loss, and acute occlusion of the central retinal artery.     

转基因骨髓间充质干细胞移植对大鼠缺血脑组织转换生长因子-β1表达的影响

目的探讨碱性成纤维细胞生长因子(bFGF)转染间充质干细胞(MSC)对大鼠缺血皮层脑组织转换生长因子-β1(TGF-β1)mRNA表达的影响。方法电穿孔法将bFGF基因转染MSCs,免疫组织化学及双标记法鉴定bFGF表达;逆转录-聚合酶链反应(RT-PCR)检测缺血脑组织TGF-β1mRNA的表达。结果移植7、14d发现转基因MSCs缺血脑组织表达bFGF。MSCs移植组和转基因MSCs移植组比较,移植后7、14d的TGF-β1mRNA表达系数分别为(0.42±0.04、0.52±0.06)和(0.33±0.05、0.36±0.04),后者更显著的降低其表达,两组比较差异有统计学意义(P<0.01)。结论转染bFGF的MSCs移植后表达bFGF,并显著下调缺血脑组织TGF-β1mRNA的表达。     

电刺激对脑缺血/再灌注大鼠脊髓背角细胞凋亡的影响

目的 观察穴位电刺激对脑缺血/再灌注大鼠脊髓背角细胞凋亡的影响. 方法 采用Longa线栓法建立大鼠左侧大脑中动脉缺血/再灌注模型,将80只大鼠按随机数字表法分为对照组(C组)和电刺激组(E组)(每组40只).E组予针刺患侧曲池、足三里穴位,C组不予干预.两组于造模后l d(T1)、3 d(T2)、7 d(T3)、14 d(T4)4个时间点随机选取10只大鼠,应用TUNEL法检测脊髓背角细胞凋亡,免疫组织化学检测caspase-3蛋白表达. 结果 两组组内比较,脊髓背角细胞凋亡率及caspase-3蛋白表达阳性细胞率,T2、T3和T4时都比T1时高(P＜0.05或P＜0.01);组间比较,E组T2、T3、T4时细胞凋亡率及caspase-3蛋白表达阳性细胞率均比C组降低,差异有统计学意义(P＜0.05),T1时两组细胞凋亡率及caspase-3蛋白表达阳性细胞率差异无统计学意义(P＞0.05). 结论 穴位电刺激可以降低脊髓背角细胞凋亡.     

Elevation of the extracellular glutamate concentration in the hippocampus after total cerebral ischemia related to the deterioration of the recovery in EEG and evoked potentials in dogs

The concentrations of extracellular glutamate (Glu), aspartate (Asp) and glycine (Gly) were measured by microdialysis method in the cortex and hippocampus before, during and after 15min of total cerebral ischemia in dogs. The correlations between the concentrations of amino acids and the changes in EEG and evoked potentials (EP) after ischemia were evaluated. Total cerebral ischemia was achieved by occluding the ascending aorta and the caval veins. The concentrations of Glu in the hippocampus significantly increased from 1.73 ± 0.59 (mean ± SEM) nmol·ml^–1 at pre-ischemia to 5.46 ± 1.34 (P 0.05) during ischemia and 14.37 ± 3.70 (P 0.01) 0–15min after ischemia, and returned to the pre-ischemic level 30min after ischemia. The concentration of hippocampal Glu 0–15min after ischemia had significant negative correlations with the EEG-EP scores (0 = serious deterioration of electrical function and 6 = normal electrical function) 30min, 3hr and 5hr after ischemia (r = –0.69, P 0.05:r = –0.67, P 0.05:r = –0.70, P 0.05, respectively). The increase of the extracellular Glu concentration in the hippocampus immediately after ischemia may aggravate the neurological outcome after total cerebral ischemia.(Ono K, Iwatsuki N, Tajima T, et al.: Elevation of the extracellular glutamate concentration in the hippocampus after total cerebral ischemia related to the deterioration of the recovery in EEG and evoked potentials in dogs. J Anesth 7: 334–340, 1993)     

Long-term effects of hypothermia on neuronal cell death and the concentration of apoptotic proteins after incomplete cerebral ischemia and reperfusion in rats

BACKGROUND: The present study investigates the long-term effects of postischemic hypothermia on neuronal cell damage and concentration changes of apoptotic proteins after cerebral ischemia. METHODS: Sixty-four Sprague-Dawley rats were anesthetized, intubated and ventilated with 2.0 Vol% isoflurane and 70% N2O/O2. After preparation the animals were randomly assigned to the following groups: group 1 (n = 32, fentanyl-N2O/normothermia 37.5 degrees C), and group 2 (n = 32, fentanyl-N2O/hypothermia 34.0 degrees C. Ischemia (45 min) was induced by common carotid artery occlusion plus hemorrhagic hypotension (MAP = 40 mmHg). Arterial blood gases and pH were maintained constant. After 1, 3, 7, or 28 days (each n = 8) the brains were removed, frozen and cut. Neuronal damage was assessed by analyzing Bax, Bcl-2, p53, and Mdm-2 proteins, activated caspases-3-positive and eosinophilic cells. A third group (n = 8) of untreated animals served as naive controls. RESULTS: In hypothermic animals, Bax concentration was decreased by 50-70% over time compared to normothermia. On days 1 and 3, Bcl-2 was increased by 50% with hypothermia. The amount of activated caspase-3-positive cells in the ischemic hemisphere was 0.5% in the hypothermic and 1-2% in the normothermic animals. Of the hippocampal cells, 10-25% were eosinophilic in both groups over time. CONCLUSION: The present data show that hypothermia prevents an ischemia-induced increase of the pro-apoptotic protein Bax for as long as 28 days and increases the concentration of the antiapoptotic protein Bcl-2 up to 3 days compared to normothermic animals. Therefore, after cerebral ischemia, hypothermia has the sustained neuroprotective potential to shift apoptosis-related proteins towards neuronal cell survival.     

Effect of dexamethasone by local treatment on cerebral edema and serum myelin basic protein after brain injury in rabbits

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