亚低温对大鼠局灶性脑缺血后细胞凋亡及Caspase-3的影响

目的 探讨亚低温对脑缺血损伤的保护作用。方法 用原位末端标记（TUNEL）和原位杂交技术分别观察亚低温组、常温组脑缺血不同时间点神经细胞凋亡的变化及Caspase-3的表达。结果 （1）常温组脑缺血后凋亡神经细胞主要分布于缺血周围区，随着时间的延长凋亡细胞数逐渐增加，至12h达高峰，24h后开始下降，7d时仍高于假手术组；（2）亚低温组脑缺血后，凋亡神经细胞也主要位于缺血周围区，数量相对较少，其变化规律与常温组相似，同一时间点相比较，亚低温组均显著低于常温组；（3）常温组脑缺血2h后，神经细胞Caspase-3开始表达，并随着时间的延长而增强，24h达高峰，其后逐渐下降，至7d略高于假手术组；（4）亚低温组脑缺血后，神经细胞Caspase-3的表达也主要位于缺血周围区，其变化规律与常温组相似，同一时间点相比较，亚低温组均显著低于常温组。结论 脑缺血后，缺血周围区神经细胞的凋亡是一个动态的渐进过程，Caspase-3基因在介导脑缺血损伤神经元凋亡过程中起关键作用。亚低温对短暂性脑缺血后的神经元凋亡有明显的抑制作用，亚低温可能通过Caspase-3途径抵抗脑缺血损伤。     

脑缺血再灌注后血管内皮细胞凋亡及其与Bcl—2表达的关系

目的 探讨大鼠局灶性脑缺血再灌注损伤后血管内皮细胞凋亡及其与Bcl-2蛋白表达的关系。方法 采用原位末端标记法和免疫组化法分别观察脑缺血再灌注2h、6h、12h、24h、2d、3d、7d、14d和21d等时间 点血管内皮细胞凋亡和Bcl-2蛋白的表达。结果 （1）脑缺血再灌注2h在缺血周围区即有凋亡内皮细胞出现,12－24h达高峰,之后逐渐下降,至21d与假手术组已无显著性差异。（2）脑缺血再灌注后2h在缺血周围区内皮细胞Bcl-2开始表达,12－24h达高峰,之后逐渐下降,至14d接近假手术组水平。（3）Bcl-2蛋白表达时相变化与内皮细胞凋亡基本一致。结论 脑缺血再灌注损伤中凋亡是血管内皮细胞的死亡形式之一,Bcl-2蛋白具有抑制缺血再灌注后血管内皮细胞凋亡的作用。     

人尿激肽原酶对大鼠局灶性脑缺血再灌注损伤的保护作用及对Caspase-3表达的影响

目的 观察人尿激肽原酶(HUK)对局灶性脑缺血再灌注损伤大鼠神经细胞凋亡及Caspase-3表达的影响. 方法 66只SD大鼠按随机数字表法分为假手术组(n=6)、缺血再灌注损伤组和HUK处理组,后两组又按不同观察时间点分为再灌注6h、12h、24 h、72 h、168 h共5个亚组(n=6).缺血再灌注损伤组和HUK处理组采用线栓法建立大鼠大脑中动脉局灶性脑缺血再灌注损伤模型,HUK处理组按浓度17.5×10-3PNAU/mL,1.0 mL/kg,于再灌注后3h尾静脉注射给药,1次/d.采用TUNEL法及免疫组化染色检测各组大鼠脑组织中凋亡细胞及Caspase-3阳性细胞的数量变化. 结果 脑缺血再灌注损伤后6h即有细胞凋亡,于24 h达到高峰,至168 h仍可见凋亡细胞.Caspase-3阳性细胞表达均于再灌注24 h达高峰,至168 h仍有较多表达.除168 h时间点外,其余各时间点HUK处理组大鼠神经细胞凋亡数量、Caspase-3阳性细胞数量均明显低于缺血再灌注损伤组,差异均有统计学意义(P＜0.05). 结论 HUK在大鼠局灶性脑缺血再灌注损伤早期(6～72h)时能抑制细胞凋亡,推测与其减少Caspase-3的表达有关.     

自由基清除剂预处理对大鼠脑缺血再灌注损伤后脑组织细胞凋亡及其相关蛋白表达的影响

目的探讨自由基清除剂依达拉奉预处理对大鼠脑缺血再灌注损伤后神经细胞凋亡及其相关蛋白Bcl-2、Bax、热休克蛋白70(HSP70)表达的影响。方法将45只雄性SD大鼠随机分为假手术组、对照组、依达拉奉预处理组,每组15只。采用线栓法制作大鼠缺血2h再灌注24h模型。预处理组大鼠建模前12h腹腔注射依达拉奉(3mg/kg),对照组给予等容量生理盐水。再灌注24h后断头取脑,应用免疫组织化学法检测Bcl-2、Bax、HSP70蛋白表达,末端脱氧核糖核酸转移酶介导的原位缺口末端标记法检测凋亡细胞。结果依达拉奉预处理组和对照组大鼠缺血周围脑组织中凋亡细胞和Bcl-2、Bax及HSP70阳性细胞数比假手术组均明显增加(P<0.01);与对照组比较,其凋亡细胞和Bax阳性细胞数均明显减少(P<0.01),而Bcl-2和HSP70阳性细胞数明显增加(P<0.01)。结论细胞凋亡在缺血再灌注损伤中起着重要作用;依达拉奉可能通过上调Bcl-2、HSP70蛋白表达、下调Bax蛋白表达减轻大鼠脑缺血再灌注后的细胞凋亡,增加脑缺血再灌注损伤耐受性,从而起到神经保护作用。     

大鼠全脑缺血再灌注损伤后调控基因Bcl-2、Bax的表达及与细胞凋亡的关系

目的:本研究旨在探讨Bcl-2及Bax蛋白在大鼠全脑缺血再灌注损伤中的变化及与细胞凋亡的关系。方法:雄性Wistar大鼠56只,随机分为假手术组、缺血15分钟再灌注1、6、12、24、48、72小时组。采用大鼠四条血管阻断方法制备大鼠全脑缺血再灌注模型。采用TUNEL法观察不同再灌注时间组海马CAl区细胞凋亡的变化。采用免疫组化法观察Bcl-2及Bax蛋白表达水平的变化。结果:脑缺血损伤后随再灌注时间延长凋亡细胞逐渐增多,至再灌注48小时达到高峰,72小时后减少。Bcl-2表达至再灌注12小时达高峰,再灌注24~72小时组逐渐减弱。Bax表达至48小时达高峰,再灌注72小时减少。结论:Bcl-2于再灌注早期表达增强,Bax于再灌注中期表达增强,Bcl-2/Bax比例失衡可能是大鼠全脑缺血再灌注后神经细胞凋亡的机制之一。     

骨髓基质细胞源神经干细胞对大鼠局灶性脑缺血神经细胞凋亡及相关蛋白表达的动态影响

目的探讨骨髓基质细胞源神经干细胞对大鼠局灶性脑缺血神经细胞凋亡及相关蛋白表达的影响。方法建立大鼠大脑中动脉缺血再灌注模型。32只健康Sprague-Dawley(SD)大鼠分为假手术组、缺血对照组、缺血骨髓基质细胞移植组和缺血骨髓基质细胞源神经干细胞移植组。分别在移植后7d和14d行脑灌注固定取材,应用免疫组化染色及原位细胞凋亡检测脑组织Bcl-2、Bax蛋白表达及凋亡细胞数。结果缺血移植组各时点的凋亡细胞数均少于缺血对照组(P<0.01),缺血移植14d组凋亡细胞数明显少于缺血移植7d组(P<0.01),骨髓基质细胞源神经干细胞移植组凋亡细胞明显少于骨髓基质细胞移植组(P<0.05)。缺血移植组Bcl-2表达显著高于缺血对照组(P<0.01)。缺血移植组Bax蛋白表达明显低于缺血对照组(P<0.01)。结论骨髓基质细胞源神经干细胞可能通过上调Bcl-2蛋白表达,下调Bax蛋白表达,对脑缺血再灌注损伤起保护作用。     

caspase-3基因在脑缺血再灌流损伤中的动态表达

目的 :探讨caspase 3基因在缺血神经细胞死亡机制中的作用。方法 :采用大鼠大脑中动脉阻塞再灌流模型 (MCAO R) ,运用RT PCR和原位杂交技术观察缺血再灌流后caspase 3mRNA表达的时空分布动态变化 ,结合TUNEL技术观察其与凋亡的关系。结果 :脑缺血 3 0min再灌流 6h和缺血 2h再灌流 1h ,caspase 3mRNA在梗死边缘区的内侧诱导表达 ,并随着缺血时间或再灌流时间的延长而增强。caspase 3基因的表达与凋亡细胞的时空动态变化趋势基本一致。结论 :脑缺血损伤诱导caspase 3基因表达增强 ,caspase 3在介导神经细胞凋亡和缺血性脑损害中起关键作用     

17-β雌二醇对大鼠脑缺血再灌注损伤细胞凋亡影响的实验研究

目的观察雌二醇对大鼠脑缺血再灌注损伤脑细胞凋亡的影响。方法72只大鼠随机分为假手术组（n=8）、实验对照组及雌二醇治疗组,后两组又进一步分为3h、6h、12h、24h4个时间点,每时间点8只。线栓法建立大鼠局灶性脑缺血再灌注损伤模型,石蜡切片HE染色及免疫组化染色检测脑组织的细胞凋亡情况及凋亡调控基因Bcl-2、Caspase-3的表达。结果雌二醇治疗组的脑组织缺血半暗带区细胞凋亡较实验对照组明显减少;随着再灌注时间的延长,治疗组半暗带区Bcl一2的表达上调而Caspase-3的表达上调减弱。结论17-β雌二醇具有减少脑缺血再灌注损伤细胞凋亡的作用,而凋亡抑制基因Bcl-2的表达升高及凋亡执行蛋白Caspase-3的表达减弱可能其是重要机制之一。     

人脂肪组织来源的神经干细胞移植对大鼠局灶性脑缺血再灌注后细胞凋亡及Bcl-2、Bax蛋白表达的影响

目的 探讨人脂肪组织来源的神经干细胞移植对大鼠局灶性脑缺血再灌注后细胞凋亡及Bcl-2、Bax蛋白表达的影响.方法 线栓法制作大鼠大脑中动脉缺血2 h再灌注模型.60只健康雄性SD大鼠随机分为4组:正常对照组(6只),假手术组(6只),缺血对照组(24只)和移植治疗组(24只);后2组又分为再灌注7 d、14 d、21 d、28 d组(各6只).体外培养脂肪基质细胞,诱导分化为神经干细胞.造模成功后24h,移植治疗组经尾静脉移植人脂肪组织来源的神经干细胞悬液(细胞浓度为2×106/ml),缺血对照组经尾静脉注射生理盐水,假手术组不做任何处理.TUNEL法检测细胞凋亡,免疫组化SABC法检测Bcl-2、Bax表达.结果 与缺血对照组比较,移植治疗组各时间点的细胞凋亡数均明显减少(均P＜0.01),Bcl-2阳性细胞数明显增高(均P＜0.01),Bax阳性细胞数明显减少(P＜0.05～0.01).结论 人脂肪组织来源的神经干细胞可能通过上调Bcl-2蛋白表达、下调Bax蛋白表达,减少局灶性脑缺血细胞凋亡;对脑缺血再灌注损伤后的神经细胞起保护作用.     

高血压大鼠局灶性脑缺血再灌注后Survivin及Bcl-2表达

目的:研究肾性高血压大鼠局灶性脑缺血再灌注后脑组织Survivin、Bcl- 2表达和细胞凋亡,探讨其意义。方法:体重2 90～3 10g肾性高血压Wistar大鼠5 0只随机分成2组:A组(缺血再灌注组)及B组(假手术组)。采用线栓法制作局灶性脑缺血2h再灌注模型,假手术组不造成缺血。用免疫组化法和TUNEL法分别观察再灌注6、12、2 4、48和72h脑组织Survivin、Bcl- 2表达和凋亡细胞。结果:在缺血再灌注组中:①再灌注6h时较多Survivin表达,到72h仍见强烈表达;②再灌注6h即可见Bcl -2表达较多,2 4h达高峰,此后逐渐下降;③再灌注6h后已出现较多凋亡细胞,在72h达高峰。假手术组及再灌注组的非缺血侧未见Survivin、Bcl- 2阳性细胞,但见0～2个凋亡细胞。结论:局灶性脑缺血再灌注后Survivin、Bcl- 2表达显著增高,细胞凋亡参与了脑缺血再灌注过程。     

Neurovascular Coupling and Cerebral Autoregulation in Patients with Stenosis of the Posterior Cerebral Artery

Neurovascular coupling and cerebral autoregulation are two brain intrinsic vasoregulative mechanisms that rapidly adjust local cerebral blood flow. This study examined if stenotic disease affects both mechanisms in the posterior cerebral artery. Ten patients with altogether 13 stenosed (≥50%) posterior cerebral artery (PCA) sides were studied. In addition, 6 control persons without a PCA stenosis were examined. Cerebral blood flow velocity was assessed from both PCAs with transcranial Doppler sonography; blood pressure was measured noninvasively via fingerplethysmography. Neurovascular coupling was assessed by a control system approach using a standard visual stimulation paradigm. Cerebral autoregulation dynamics were measured from spontaneous oscillations of blood pressure and cerebral blood flow velocity by transfer function analysis (phase and gain). The parameters of neurovascular coupling and cerebral autoregulation did not show relevant differences between controls, nonstenosed sides, and stenosed sides. The 3 severely stenosed PCA sides showed a trend to a minor functional flow velocity change and attenuation of the neurovascular coupling mechanism in relation to sides with moderate stenosis. Phase and gain were not altered on sides with PCA stenosis. We conclude that in a group of patients with mainly moderate stenosis of the PCA neurovascular coupling and dynamic autoregulation dynamics seem to be unaltered.     

Cerebral Vasospasm and Delayed Cerebral Ischemia in Intraventricular Hemorrhage

Background

Intracerebral hemorrhage (ICH) with intraventricular extension (IVH) is a devastating disease with a particular high mortality. In some aspects, IVH may resemble subarachnoid hemorrhage. The incidence and role of cerebral vasospasm in ICH with IVH are poorly understood. Here, we aimed to analyze the incidence and relationship of cerebral vasospasm to clinical characteristics, in-hospital mortality, and functional outcome at 3 months in patients suffering ICH with IVH.

Methods

Patients with ICH and IVH treated on a neurological intensive care unit were prospectively enrolled in a single-center observational study. Vasospasm was defined using established ultrasound criteria. Delayed cerebral ischemia (DCI) was defined as a new hypodensity on follow-up cranial CT. Functional outcome at 3 months was assessed using the modified Rankin Scale.

Results

129 patients with ICH and IVH were screened for the study. 62 patients entered the final analysis. The incidence of significant vasospasm was 37 %. A strong trend was found for the association between all cerebral vasospasm and DCI (P = 0.046). Early (up to 48 h) vasospasm was significantly associated with a DCI (P = 0.033). Overall mortality and outcome after 3 months did not differ between the groups.

Conclusion

Cerebral vasospasm seems to be a frequent complication after ICH with IVH and might be associated with DCI. Larger studies are warranted to confirm this hypothesis.     

Cerebral infarcts and seizures in the neonate

A retrospective analysis was performed on 54 infants who suffered perinatal hypoxic-ischemic insults and came to autopsy, in an attempt to assess the association of cerebral infarcts with seizures. Fifty infants had several types of cerebrovascular lesions, including intraventricular hemorrhage (32 cases), periventricular leukomalacia (24), ischemic neuronal necrosis (18), pontosubicular necrosis (12), cerebral infarct (9), and cerebellar hemorrhage (7). Of these infants, nine had electroencephalographic seizures. Among a variety of cerebrovascular lesions, cerebral infarcts represented the single lesion most highly correlated with seizures. The incidence of seizures in infants with cerebral infarcts (44%) was significantly higher than with other types of vascular lesions.     

Cerebral haemodynamics and depression in the elderly

BACKGROUND: Evidence from epidemiological and neuroimaging studies suggests that cerebrovascular disease is associated with depressive disorders in the elderly, but the extent to which it contributes to the pathogenesis of late life depression is unclear. OBJECTIVE: To investigate the relation between cerebral haemodynamics and depression in a population based study, using transcranial Doppler ultrasonography. METHODS: Cerebral blood flow velocity and CO2 induced vasomotor reactivity in the middle cerebral artery were measured in 2093 men and women who participated in the Rotterdam study. All subjects were screened for depressive symptoms using the Center of Epidemiological Studies Depression scale, and those with a score of 16 or over had a psychiatric work up. In a semistructured interview, diagnoses of depressive disorders according to the DSM-IV and subthreshold depressive disorder were established. Analyses of covariance controlled for age, sex, stroke, cognitive score, and cardiovascular risk factors were used to compare means of haemodynamic variables. RESULTS: Subjects with depressive symptoms had reduced blood flow velocities (mean difference, -2.9 cm/s; 95% confidence interval (CI), -5.0 to -0.8; p = 0.008) and lower vasomotor reactivity (mean difference -0.5%/kPa; 95% CI, -1.0 to -0.05; p = 0.03). Blood flow velocity was reduced most in subjects suffering from a DSM-IV depressive disorder (mean difference, -4.9 cm/s; 95% CI, -8.5 to -1.4; p = 0.006). The overall reduction in vasomotor reactivity was accounted for by subjects with subthreshold depressive disorder. CONCLUSIONS: Depression in late life is associated with cerebral haemodynamic changes that can be assessed by transcranial Doppler ultrasonography. The observed reduction in cerebral blood flow velocity could be a result of reduced demand in more seriously depressed cases with a DSM-IV disorder, whereas reduced CO2 induced cerebral vasomotor reactivity is a possible causal factor for subthreshold depressive disorder.     

脑小血管病和脑微循环研究进展

脑小血管病（cerebral s mall v essel d isease, C SVD）指由脑微循环（包括脑小血管或微血管） 的病理变化而引起的急性卒中、认知功能障碍等多种临床表现。脑微循环的动脉粥样硬化与栓塞、 内皮功能障碍与血脑屏障破坏、淀粉样蛋白沉积、血流低灌注及静脉胶原性疾病与其发病机制密切 相关,并为其治疗提供了新的策略。脑小血管病的明确诊断依赖组织活检,但此时常常是疾病的终末 期,且组织病理难以获得,故临床上主要依靠神经影像学来获得诊断。本文就脑小血管病的临床表 现、分类、微循环相关性病理生理机制及临床微循环检查方法进行阐述,以期寻找脑小血管病新的 诊断与治疗策略。     

经颅多普勒超声评价脑血管反应性和脑血流自动调节

经颅多普勒超声（transcranial Doppler,TCD）能无创、快速地对脑血流动力学进行检查和监 测,被称为脑血管的“听诊器”。目前,TCD不仅用于脑血管痉挛或狭窄等的检查,还被用于脑血管反 应性（cerebral vasoreactivity,CVR）和脑血流自动调节（cerebral autoregulation,CA）的研究,从而预测 卒中发生风险和预后,评估自主神经功能障碍。本文就TCD评价CVR和CA的临床应用价值进行综述, 旨在扩大其应用范围。     

脑淀粉样血管病变与脑微出血

脑淀粉样血管病（CAA）是造成血压正常的老年人自发性皮质．皮质下脑内出血的重要原因。由于很多病例无症状,对共诊断及预防受到很大限制。研究显示,脑微出血（CMB）和CAA的发生与预后密切相关,本研究仅对CAA与CMB的相关性做一综述。     

无症状性脑梗塞患者脑血流灌注的相关研究

目的:探讨无症状性脑梗塞(Slient Cerebral lnfarction,SCl)患者的脑血流灌注状况,确定监测病情变化的有效手段。方法:采用Diamox药物负荷,99mTc-ECD SPECT核素显像技术,对20例SCI患者及15例正常对照组进行静态时及负荷后脑血流定量测定。结果:1、静态显像时,SCI组大脑平均脑血流量、额、颞、顶叶皮质及基底节区局部脑血流较对照组轻度降低(P<0.05),负荷后与对照组相比血流降低更加明显(P<0.01);2、危险因素种类个数与SCI患者平均脑血流变化呈有意义的负相关(r=-0.5648,P<0.05)。结论:SCI患者脑血流灌注处于低下状态,脑血管代偿能力降低;2、危险因素的累积作用进一步降低SCI患者的血流灌注;负荷脑血流定量检测技术能客观地反映SCI的脑循环动态情况,可作为有效的病情监测手段。     

Diffuse Cerebral Intravascular Coagulation and Cerebral Infarction in Pneumococcal Meningitis

Background

There is a widely held belief that cerebral infarction after bacterial meningitis is always caused by vasculitis; however, evidence is weak. We hypothesized that diffuse cerebral intravascular coagulation is an additional explanation of cerebral infarction in patients with pneumococcal meningitis.

Methods

Sixteen brains of adults who died from pneumococcal meningitis were investigated. Clinical data were collected, and brain sections were scored for signs of inflammation and activation of coagulation. Patients with and without cerebral infarction on autopsy were compared.

Results

In total, 38% of patients had focal neurological deficits. Patients died at a median of 7 days (range, 0–32 days) after admission. On autopsy, the nine patients (56%) with cerebral infarctions more often had arterial thrombosis (p = 0.04) than patients without infarction. Patients with infarction tended to have more inflammatory infiltrations of brain parenchyma, microvascular proliferation, small vessel vasculitis/endarteritis obliterans, blood clotting/vessel clogging, and venous thrombosis. None of the patients had large vessel vasculitis. Five patients had cerebral infarctions without vasculitis or endarteritis obliterans. Although four patients with cerebral infarctions had small vessel vasculitis or endarteritis obliterans, areas of infarction could not be localized to the blood flow distribution of these vessels. Blood clotting/vessel clogging was seen in all four patients with vasculitis or endarteritis obliterans, but this was also observed in 10 patients without vasculitis or endarteritis obliterans. None of the patients developed disseminated intravascular coagulation.

Conclusions

Our results suggest that diffuse cerebral intravascular coagulation is an additional explanation of cerebral infarction complicating pneumococcal meningitis.