溶血磷脂酸对血脑屏障及AQP4蛋白表达的影响

目的 研究溶血磷脂酸对大鼠血脑屏障通透性及水孔蛋白-4(aqaporin-4,AQP4)表达的影响.方法 在立体定向仪下向大鼠右侧尾壳核注射50uL溶血磷脂酸,在不同时间点对注射部位邻近脑组织AQP4蛋白进行免疫组化检测;用伊文斯蓝(Evans blue, EB)作为示踪剂定量测定不同时间点血脑屏障(Blood-brain barrier,BBB)通透性.结果 注射溶血磷脂酸后6 h尾壳核AQP4蛋白表达开始增高,在第2 d达到高峰,并维持到第3 d,以后逐渐下降. 表达增高的部位主要为微血管内皮细胞及其周围的胶质细胞.与对照组各时间点相比,均有显著性差异;LPA注射后6 h同侧尾壳核区BBB对EB通透性开始增加,24 h达最大,到48 h逐渐减低,与对照组相同时间点比差异有显著性(p<0.05).结论 溶血磷脂酸可以促进脑微血管内皮细胞及其周围胶质细胞AQP4蛋白表达的增加,引起血脑屏障通透性的增加,参与脑水肿的发生.     

V1a受体拮抗剂对脑出血大鼠水孔蛋白-4表达的影响及血脑屏障通透性的研究

目的研究血管加压素1a受体(V1aR)拮抗剂对脑出血(in tracerebra l hem orrhage,ICH)后水孔蛋白-4(aquaporin-4,AQP 4)表达及血脑屏障(BBB)通透性的影响。方法运用立体定向技术,尾动脉采血制作大鼠脑出血模型。模型制作成功后,治疗组侧脑室注射V1aR拮抗剂,对照组仅注射等量人工脑脊液。采用免疫组化技术对血肿周围组织AQP 4蛋白进行检测。通过检测渗出到脑血管外的伊文斯蓝(Evans B lue,EB)的含量来定量观察BBB的通透性。结果脑出血后6h尾壳核血肿周围组织AQP 4蛋白表达开始增高,在脑出血1d达高峰(P<0.01),持续到3d以后逐渐下降,到7d仍高于正常水平。而用V1aR拮抗剂脑室注射后,AQP 4蛋白表达在各时间点表达明显降低。BBB通透性在脑出血后6h开始升高,1d达高峰(P<0.01),3d后回落,侧脑室注入V1aR拮抗剂后,BBB通透性与对照组比较明显下降(P<0.05)。结论V1aR拮抗剂能抑制AQP 4蛋白的表达,保护BBB,减轻脑出血后脑水肿。     

局部亚低温对脑出血后水肿影响的实验研究

目的探讨局部亚低温对大鼠脑出血后水肿形成的影响及其可能机制。方法雄性Wistar大鼠230只随机分为:对照组;脑出血组;脑出血加局部亚低温组;凝血酶加局部亚低温组。应用Evans-Blue测定血脑屏障(BBB)通透性,应用干湿重法测定脑水含量。结果与对照组相比,大鼠注血后6h开始出现脑组织水含量和BBB通透性的增加,在72h达到高峰,然后逐渐消退。不同时程局部亚低温均可以显著降低脑出血后72h时脑组织水含量及BBB通透性(P<0.01),其中给以4h局部亚低温时,降低最明显。注射凝血酶6h后,脑组织水含量及BBB通透性显著增高(P<0.01),于24~48h达高峰,然后逐渐下降。凝血酶 局部亚低温组在各个时间点与凝血酶组相比,脑组织水含量及BBB通透性明显降低(P<0.01)。结论局部亚低温可能是通过抑制凝血酶的毒性作用来减轻脑出血后水肿的形成及血脑屏障的破坏。     

黄体酮对脑缺血再灌注大鼠紧密连接蛋白ZO-1和occludin表达的影响

目的探讨黄体酮对大鼠局灶性脑缺血再灌注后血脑屏障紧密连接蛋白ZO-1、occludin表达及血脑屏障通透性的影响。 方法将42只健康雄性SD大鼠按随机数字表法分为假手术组（6只）和缺血再灌注组,后者再按再灌注时间分为缺血2h再灌注3h、6h、12h、24 h、48 h及72h组（各6只）。缺血再灌注组用线栓法制备成大鼠大脑中动脉缺血再灌注模型。采用荧光分光光度法测定缺血侧脑组织中伊文氏蓝(EB)含量来评价血脑屏障的通透性,Western blotting法检测脑组织ZO-1和occludin的表达。取EB漏出最多组的时间点,增设黄体酮干预组和溶剂对照组（各6只）,与相同时间点的缺血再灌注组比较,观察黄体酮对ZO-1、occludin表达及血脑屏障通透性的影响。 结果 缺血2h再灌注3h时脑组织EB含量开始增加,再灌注24 h时达高峰;ZO-1、occludin的表达在缺血2h再灌注3h时开始下降,再灌注24 h时达最低。黄体酮干预组EB含量明显低于缺血2h再灌注24 h组,差异有统计学意义(P＜0.05)。黄体酮干预组ZO-1和occludin的表达水平均明显高于缺血2h再灌注24 h组,差异有统计学意义(P＜0.05)。 结论 黄体酮町抑制缺血再灌注大鼠紧密连接蛋白ZO-1和occludin表达的降低,从而起到保护血脑屏障的作用。     

急性创伤性脑损伤大鼠血脑屏障通透性变化与Claudin-5的相关性研究

目的 研究大鼠急性创伤性颅脑损伤(TBI)后血脑屏障(BBB)通透性的变化和机制.方法 雄性Wistar大鼠96只按随机数字表法分为假手术组和TBI组,TBI模型参照Feeney自由落体致伤法制作,假手术组仅行开颅术不行打击致伤.每组按伤后处死时间的不同分为3h、6h、12h 、24 h、48 h、72h6个亚组,每亚组4只.采用干湿重比法测定脑组织含水量,Western blotting检测脑皮质紧密连接蛋白Claudin-5的表达,伊文思蓝(EB)法检测脑组织BBB通透性变化. 结果 与假手术组比较,TBI组大鼠创伤后不同时间点脑组织含水量、EB含量均增多.组内比较显示二者创伤后3h开始增多,24 h达高峰,随后下降,差异有统计学意义(P＜0 05);与假手术组比较,TBI组大鼠创伤后6h、12h、24 h、48 h、72 h紧密连接蛋白Claudin-5表达降低.组内比较显示其创伤后6h表达降低,24 h达最低值,随后回升,差异有统计学意义(P＜0.05);大鼠脑Claudin-5蛋白的相对表达水平和脑组织水含量、脑组织EB含量呈负相关关系(r=-0.994,P=0.000;r=-0.846,P=0.036).脑组织含水量和EB含量呈正相关关系(=0.863,P=0.027). 结论 TBI后大鼠BBB通透性变化和脑损伤程度具时间依赖性,紧密连接蛋白Claudin-5与BBB变化具有一定程度的相关性.     

腺苷预处理对缺血性脑卒中大鼠血脑屏障通透性及AQP4表达的影响

目的通过观察腺苷预处理对缺血性脑卒中大鼠梗死区周边脑组织血脑屏障(blood brain barrier,BBB)通透性和AQP4表达的影响,从血脑屏障的角度探讨腺苷预处理对脑组织的作用及其可能的机制。方法将SD(Sprague-Dew ley)大鼠随机分为对照组(F组)、模型组(IR组)、腺苷预处理组(AP组),依术后处死动物时间的不同,每组再分为4个亚组:6 h、24 h、48 h和72 h组。采用干湿重法测定脑水含量;伊文思蓝(evans blue,EB)渗透法分析血脑屏障通透性变化;免疫组织化学法检测不同时间点梗死灶周围AQP4蛋白的表达。结果①AP组脑水含量显著低于IR组,差异具有统计学意义(P 0.05)。②IR组和AP组EB渗出量较F组均明显增多,差异具有统计学意义(P 0.05); AP组EB渗出量显著低于IR组,但高于F组,有显著差异(P 0.05)。③IR组和AP组AQP4表达均高于F组,有显著差异(P 0.05); AP组较IR组,AQP4表达明显下降,差异具有统计学意义(P 0.05)。④IR组和AP组两组组内比较,EB渗出量48 h时达高峰后开始下降但仍高于正常水平,AQP4表达在48 h也达高峰;大鼠脑缺血再灌注损伤后各时间点梗死区周围脑组织血脑屏障通透性变化与AQP4表达变化呈显著正相关(r=0.898,P 0.001)。结论腺苷预处理具有改善血脑屏障通透性起到脑保护的作用,其作用可能是通过降低AQP4蛋白的表达来实现的。     

溶血磷脂酸对大鼠小胶质细胞TLR4表达的影响

目的探讨溶血磷脂酸(LPA)在大鼠体内对海马小胶质细胞Toll-样受体4(Toll-like receptor4,TLR4)表达的影响和机制。方法向SD大鼠右侧海马区立体定向注射LPA、LPA+苏拉明(L+S),免疫组化检测不同时间点注射部位临近脑组织TLR4表达。结果 LPA脑内注射后6h同侧海马区TLR4表达开始增高,24h达高峰,48h以后逐渐下降,与对照组相同时间点比较差异有显著性(P<0.05),L+S脑内注射组各时间点与LPA组相应时间点相比表达明显下降(P<0.01)。结论 LPA激活小胶质细胞可能是通过TLR4信号途径介导的,TLR4可能在脑出血炎症损伤中具有一定作用。     

大鼠脑出血周边组织MMP-9、TIMP-1表达对脑水肿的影响

目的:研究大鼠脑出血周边组织基质金属蛋白酶系(MMPs)的成员明胶酶-9(MMP-9)和内源性基质金属蛋白酶抑制物(TIMP-1)表达对脑水肿的影响。方法:Wister大鼠50只随机分为对照组、出血组,各组又分为6、24、48、72、120h等5个时间点。测定脑组织含水量、脑组织示踪剂伊文思蓝(EB)含量和MMP-9、TIMP-1表达。结果:出血后脑组织含水量在72h、EB含量在48h、MMP-9和TIMP-1表达在48h达到高峰,血脑屏障(BBB)在各时间点均有破坏。结论:出血后MMP-9表达可导致BBB通透性增加,TIMP-1通过抑制MMP-9的表达减轻脑水肿。     

乌司他丁对脑缺血再灌注损伤大鼠血脑屏障通透性和MMP-9活性的影响

目的 观察乌司他丁对大鼠局灶脑缺血再灌注损伤后血脑屏障(BBB)通透性和基质金属蛋白酶-9(MMP-9)活性的影响.方法 采用栓线法制备大鼠局灶性脑缺血再灌注损伤模型,腹腔注射乌司他丁,于脑缺血再灌注后6h、24h、48h、72h处死大鼠.通过测定损伤侧脑组织中伊文思蓝(EB)含鼍来观察BBB通透性的改变,用明胶酶谱法检测同侧脑部MMP-9活性变化.结果 脑缺血再灌注损伤后,大鼠EB含量增加,24h最明显;MMP-9活性明显升高,48h达高峰.乌司他丁处理组EB含量及MMP-9活性水平明显低于脑缺血再灌注组(P<0.05).结论 乌司他丁可抑制脑缺血再灌注后大鼠MMP-9的活性,减轻BBB通透性的破坏.     

Mg对单纯疱疹病毒性脑炎小鼠水孔蛋白-4表达的影响及血脑屏障通透性的研究

目的 研究镁剂对单纯疱疹病毒性脑炎(Herpes simplex encephalitis,HSE)后水孔蛋白-4(aquaporin-4,AQP4)表达、血脑屏障(BBB)通透性及神经功能的影响.方法 小鼠脑内接种HSV-1病毒,治疗组静脉注射硫酸镁,对照组仅注射等量生理盐水.采用免疫组化技术对感染侧脑组织AQP4蛋白进行检测.通过检测渗出到脑血管外的伊文斯蓝(Evans Blue,EB)的含量来定量观察BBB的通透性.HSV-1病毒感染后5d对小鼠进行神经功能评分.结果 造模后第3天,脑组织AQP4的表达增加,第5天时更加明显(P<0.01),与血脑屏障通透性增高相一致,给与硫酸镁治疗后,血脑屏障通透性及AQP4的表达均明显降低(P<0.01),伴随着神经功能的改善.结论 镁剂能抑制AQP4蛋白的表达,保护BBB,改善脑炎后神经功能.     

Denervation study of synapses of organ of corti of old world monkeys

Fine structural characteristics of synapses in the spiral organ of Corti were examined, with reference to differences between inner and outer haircell systems, and to location of neurons of origin of efferent axons. Surgical interruption of crossed olivocochlear bundle, of vestibular nerve, of facial nerve, and excision of superior cervical ganglia were used to determine the pathways of efferent axons. Interruption of the vestibular nerve near the brainstem results in degeneration of all efferent terminals on outer hair cells. Mid-line lesions at, and caudal to, the facial colliculus result in degeneration of about half of these efferent terminals. Efferent synaptic bulbs to the inner hair-cell system are small, of the order of one micron, and form type 2 junctions with afferent dendrites. They tend to have more large dense-core vesicles (about 80 nm) than the large efferent terminals of the outer hair-cell system, and appear to be the terminals of axons in the habenula perforata, which exhibit varicosities laden with large dense core vesicles. The varicosities are unaffected by excision of the superior cervical ganglia. So far as our material can reveal, it appears that the varicosities in the habenula perforata do not survive vestibular root interruption, nor do the efferent processes in the internal spiral bundle or at the base of inner hair cells. Most interestingly, the afferent processes of the inner hair-cell system, as identified for example by their relation to pre-synaptic bodies in the inner hair cells, are subject to a trans-synaptic reaction after severance of the vestibular root. They undergo a dramatic cytological transformation, characterized by increase of volume, engorgement with microtubules, microfilaments, microvesicles of various sizes, and clusters of lysosomes. Thus, both the efferent and afferent terminals of the inner hair-cell system show marked cytological differences from the corresponding terminals of the outer hair cell system.     

Mechanism of action of tubocurarine on nicotinic cholinoreceptors of neurons of the sympathetic ganglia of rats

Tubocurarine (Tc) effect on membrane currents elicited by acetylcholine (ACh) was studied in isolated superior cervical ganglion neurons of rat using patch-clamp method in the whole-cell recording mode. The "use-dependent" block of ACh current by Tc was revealed in the experiments with ACh applications, indicating that Tc blocked the channels opened by ACh. Mean lifetime of Tc-open channel complex, tau, was found to be 9.8 +/- 0.5 s (n = 7) at -50 mV and 20-24 degrees C. tau exponentially increased with membrane hyperpolarization (e-fold change in tau corresponded to the membrane potential shift by 61 mV). Inhibition of the ACh-induced current by Tc (3-30 microM/1) was completely abolished by membrane depolarization to the level of 80-100 mV. Inhibition of ACh-induced current was augmented at increased ACh doses. It is concluded that the open channel block produced by Tc is likely to be the only mechanism for Tc action on nicotinic acetylcholine receptors in superior cervical ganglion neurons of rat.     

The effect of age of onset of PD on risk of dementia

Background Dementia occurs in the majority of patients with Parkinson’s disease (PD). Late onset of PD has been reported to be associated with a higher risk for dementia. However, age at onset (AAO) and age at baseline assessment are often correlated. The aim of this study was to explore whether AAO of PD symptoms is a risk factor for dementia independent of the general effect of age. Methods Two community-based studies of PD in New York (n = 281) and Rogaland county, Norway (n = 227) and two population-based groups of healthy elderly from New York (n = 180) and Odense, Denmark (n = 2414) were followed prospectively for 3–4 years and assessed for dementia according to DSM-IIIR. All PD and control cases underwent neurological examination and were followed with neurological and neuropsychological assessments. We used Cox proportional hazards regression based on three different time scales to explore the effect of AAO of PD on risk of dementia, adjusting for age at baseline and other demographic and clinical variables. Findings In both PD groups and in the pooled analyses, there was a significant effect of age at baseline assessment on the time to develop dementia, but there was no effect of AAO independent of age itself. Consistent with these results, there was no increased relative effect of age on the time to develop dementia in PD cases compared with controls. Interpretation This study shows that it is the general effect of age, rather than AAO that is associated with incident dementia in subjects with PD. Received in revised form: 22 December 2005     

Limits of deinstitutionalization--perspectives of relatives of psychiatric patients

After a hopeful beginning, the social process of the reintegration of those with severe mental illness has come to a standstill. I am led to wonder whether "the community" really wants to live together with people suffering from severe mental illness, and if so, how closely? As long as the medical treatment of mental illness provided by the general practitioners is fundamentally deficient, as they are not able to prescribe the necessary interventions--such as out-patient psychiatric nursing, and service providers in the out-patient sector are content with offering increasingly intensive forms of care for the less seriously ill at the cost of the Social Welfare System--the reintegration of those with serious mental illness remains an illusion--which is mainly to the benefit of providers of residential care in homes and hostels.