ACEI对肾性高血压大鼠脑缺血再灌注后细胞凋亡的影响

目的观察血管紧张素转化酶抑制剂(ACEI)对肾性高血压大鼠脑缺血再灌注后神经功能和细胞凋亡的影响,探讨ACEI的脑保护机制。方法采用狭窄肾动脉方法建立肾性高血压大鼠模型,随机分依那普利组(A组)和高血压缺血再灌注组(B组);正常血压组分为假手术组(C组)和缺血再灌注组(D组)。用线栓法造成大脑缺血再灌注模型,缺血时间为2h,再灌注时间22h。用免疫组织化学技术检测脑组织bcl-2、bax的表达,TUNEL法检测细胞凋亡。结果(1)脑缺血再灌注后神经功能评分:A组神经功能评分较B组和D组降低(P<0.05,);D组神经功能评分低于B组(P<0.05)。(2)A组与B组和D组比较bcl-2表达明显增多(P<0.05),bax表达显著降低(P<0.05),神经细胞凋亡明显减少(P<0.05);B组与D组比较,bcl-2表达明显降低(P<0.05),bax表达明显增加(P<0.05),而神经细胞凋亡明显增多(P<0.05)。结论ACEI明显改善局灶性脑缺血大鼠的神经功能,减少神经细胞凋亡,上调脑组织bcl-2表达,抑制bax表达,提示对脑缺血再灌注损伤有脑保护作用。     

粒细胞集落刺激因子对大鼠脑缺血再灌注损伤脑Caspase-3与细胞色素C表达的影响

目的探讨粒细胞集落刺激因子(G-CSF)在大鼠脑缺血再灌注损伤中的神经保护作用机制。方法将36只健康成年雄性SD大鼠随机分为假手术组、缺血再灌注组、G-CSF治疗组,每组12只。采用线栓法制作大鼠大脑中动脉缺血再灌注模型,于脑缺血2 h再灌注0 h及24 h给予G-CSF治疗组G-CSF(按体质量50μg/kg)腹部皮下注射,给予假手术组和缺血再灌注组等量生理盐水。采用Longa评分法进行神经功能评分,采用免疫组化法检测各组大鼠脑组织细胞色素C、半胱氨酸蛋白酶-3(Caspase-3)表达水平,应用原位末端转移酶标记(TUNEL)检测神经细胞凋亡情况,TTC染色检测脑梗死体积。结果假手术组大鼠未发现脑梗死病灶,细胞色素C和Caspase-3阳性细胞数及凋亡细胞亦少见。G-CSF治疗组细胞色素C、Caspase-3阳性细胞数及凋亡细胞数均较缺血再灌注组明显减少(P<0.01);缺血再灌注组和G-CSF治疗组均可见大脑中动脉供血区梗死灶,但G-CSF治疗组梗死灶较缺血再灌注组明显缩小(P<0.01),神经功能明显改善。结论 G-CSF对脑缺血再灌注损伤有神经保护作用,其作用机制可能通过阻断线粒体/细胞色素C途径抑制细胞凋亡。     

吸氧预处理对大鼠局灶脑缺血神经细胞凋亡及Bcl-2、Bax的影响

目的 观察吸氧预处理对大鼠局灶脑缺血再灌注后细胞凋亡及凋亡相关基因Bax、Bcl-2的关系,探讨吸氧预处理的脑保护作用.方法 采用线栓法阻塞大鼠大脑中动脉造成局灶脑缺血再灌注模型,用TUNEL染色标记神经细胞凋亡,免疫组化染色观察Bax,Bcl-2蛋白含量.结果 与模型组相比,吸氧预处理组半暗区的TUNEL阳性细胞数和Bax蛋白表达阳性细胞数明显下降,(P<0.05),Bcl-2蛋白表达细胞数明显上升(P<0.05).结论 吸氧预处理可通过抑制缺血再灌注后神经细胞凋亡和减少Bax的表达,增加Bcl-2蛋白的表达发挥脑保护作用.     

依达拉奉对大鼠局灶性脑缺血再灌注损伤后细胞凋亡及caspase-3蛋白表达的影响

目的 探讨依达拉奉对大鼠局灶性脑缺血再灌注损伤后神经功能损伤、细胞凋亡及caspasc-3蛋白表达的影响.方法 雄性SD大鼠24只采用随机数字表法分为假手术组、脑缺血再灌注组、生理盐水治疗组、依达拉奉治疗组,每组6只.除假手术组外,其余3组均采用大脑中动脉线栓法制作大鼠局灶性脑缺血再灌注损伤模型.依达拉奉治疗组于脑缺血开始时及再灌注后12 h分别腹腔注射依达拉奉3 mg/kg,生理盐水治疗组同时间注射等量生理盐水;假手术组同样过程造模,但不插入尼龙线造成缺血.造模后24 h后进行大鼠神经行为学评分;应用免疫组织化学及Western blot检测caspase-3蛋白表达水平的变化;利用原位缺口末端标记法(TUNEL法)研究神经细胞凋亡的变化.结果 与脑缺血再灌注组及生理盐水治疗组相比,依达拉奉治疗组大鼠神经行为学评分明显减少,caspase-3免疫阳性细胞及蛋白表达明显减少,凋亡细胞也减少,差异均有统计学意义(P<0.05).结论 依达拉奉能有效减轻脑缺血灌注损伤后神经细胞凋亡.改善神经功能缺损症状,推测其机制与抑制caspase-3蛋白表达有关.     

乌司他丁对脑缺血-再灌注大鼠脑组织细胞色素C、凋亡诱导因子表达及凋亡细胞数的影响

目的探讨乌司他丁对脑缺血-再灌注大鼠脑组织细胞色素C、凋亡诱导因子(AIF)表达及凋亡细胞数的影响。方法 54只SD大鼠随机分成假手术组、脑缺血-再灌注组(对照组)、脑缺血-再灌注+乌司他丁治疗组(治疗组)。采用大脑中动脉线栓法制作大鼠局灶性脑缺血-再灌注损伤模型。治疗组再灌注时,腹腔注射乌司他丁2万U/kg。采用免疫组化法检测大鼠脑组织细胞色素C表达,采用逆转录(RT)-PCR法检测大鼠脑组织AIF表达,采用原位末端标记法检测大鼠脑组织凋亡细胞数。结果对照组和治疗组大鼠脑组织皮质区细胞色素C、AIF的表达及凋亡细胞数均明显高于假手术组(均P<0.05),但治疗组大鼠脑组织皮质区细胞色素C、AIF的表达及凋亡细胞数明显低于对照组(均P<0.05)。结论乌司他丁抑制细胞凋亡可能与下调脑缺血-再灌注大鼠脑组织细胞色素C、AIF的表达,减轻线粒体损伤,抑制线粒体通路的凋亡途径有关。     

炎性介质阻断剂对大鼠脑缺血再灌注损伤后神经功能缺损、细胞凋亡及半胱氨酸蛋白酶-3表达的影响

目的探讨炎性介质阻断剂AG490对大鼠局灶性脑缺血再灌注损伤后神经功能缺损、细胞凋亡及半胱氨酸蛋白酶-3(caspase-3)表达的影响。方法雄性SD大鼠被随机分为假手术组、缺血再灌注组、生理盐水组、AG490组;采用大脑中动脉线栓法制作大鼠局灶性脑缺血再灌注模型;AG490组于脑缺血即刻及再灌注后12 h分别腹腔注射AG490 1 mg/kg。再灌注24 h后对各组大鼠进行神经功能缺损评分;利用原位缺口末端标记法(TUNEL法)检测神经细胞凋亡数;应用Western Blot法检测各组脑组织磷酸化酪氨酸蛋白激酶(P-JAK2)、磷酸化信号转导和转录激活因子(P-STAT3)、caspase-3表达。结果与缺血再灌注组及生理盐水组比较,AG490组大鼠神经功能缺损评分明显减低(均P<0.05);凋亡细胞数及P-JAK2、P-STAT3、caspase-3表达明显减少(均P<0.01)。结论AG490可阻断JAK2/STAT3细胞因子信号转导通路,有效抑制caspase-3表达,减轻缺血灌注损伤后神经细胞凋亡,改善神经功能缺损症状。     

脑缺血再灌注损伤时 c-fos、c-jun 的表达和细胞凋亡

目的　研究脑缺血再灌注大鼠神经细胞凋亡和原癌基因c fos、c jun表达。 方法　 8周龄健康雄性Wistar大鼠 2 4只 ,随机分为缺血再灌注组、假手术组和对照组 ,每组各 8只。制作大鼠大脑中动脉栓塞 (MCAO)再灌注模型 ,缺血 4h再灌注 2h后断头处死 ,TUNEL法检测神经细胞凋亡 ,免疫组织化学法检测神经细胞c fos、c jun蛋白的表达。结果　缺血再灌注组细胞凋亡率、平均吸光度及c fos、c jun阳性细胞率、平均吸光度均高于假手术组和对照组 (P <0 .0 5 )。结论　脑缺血再灌注损伤可诱导c fos、c jun蛋白的表达和细胞凋亡 ;脑缺血再灌注大鼠神经功能评分与c fos、c jun蛋白的表达和细胞凋亡呈正相关。     

葛根素对大鼠全脑缺血再灌注后学习记忆障碍保护作用及其机制的研究

目的 探讨葛根素对大鼠全脑缺血再灌注后学习记忆能力的影响及其机制。方法 采用四血管阻断法建立SD大鼠全脑缺血再灌注损伤模型，暗回避反应法测定学习记忆能力，并应用免疫组织化学法、原位末端标记法，检测大鼠全脑缺血再灌注海马CA，区的bcl-2阳性细胞数、凋亡细胞数的动态变化。结果 (1)与再灌注组相比，葛根素组大鼠潜伏期明显延长；(2)脑缺血再灌注后，海马CA1区bcl-2蛋白的表达随再灌注时间不同而变化，缺血20min后再灌注24h达高峰，葛根素组bcl2蛋白的表达于相应的时间点明显增多；(3)脑缺血再灌注后海马CA1区神经元凋亡损伤在再灌注72h损伤最重，葛根素组可减少相应时点神经细胞凋亡数。结论 葛根素对全脑缺血再灌注后大鼠学习记忆能力具有明显的改善作用，其作用机制可能与通过上调bcl-2基因表达从而抑制或延迟脑缺血再灌注后细胞凋亡有关。     

腺病毒介导kallikrein基因过度表达对脑梗死周边区细胞凋亡的作用

目的 探讨激肽释放酶(kallikrein)对脑梗死周边区域缺血神经细胞凋亡的作用.方法 建立大鼠大脑中动脉闭塞(MCAO)模型,将造模成功的30只大鼠采用随机数字表法分为以下几组:A组,空白对照组;B组,注射生理盐水;C组,注射pAdCMV-人类组织激肽释放酶(HTK):每组10只.观察每组大鼠处理前后神经功能损害评分(NSS),用免疫组化技术检测外源性HTK的表达,并通过TUNEL染色、RT-PCR检测细胞凋亡及凋亡因子bcl-2、bax、caspase-3 mRNA水平.结果 治疗后24h在C组中可见HTK表达阳性细胞并逐渐增多,72h后达高峰.与B组以及A组相比差异有统计学意义(112±6.1、68±4.2、59±3.9,P<0.05).治疗后72h,C组大鼠NSS神经功能评分明显低于B组以及A组(6.70±0.16、8.13±0.16、7.93±0.20,P<0.05);治疗后7 d差异更明显(5.14±0.18、7.82±0.14、7.91±0.10,P<0.01).凋亡神经细胞集中于梗死周边区,治疗后72h及7d时,C组平均TUNEL阳性细胞数较B组与A组明显减少(72 h:10.1±0.9、16.7±1.1、20.4±0.8;7 d:15.2±1.2、33.6±1.3、28.8±1.7,P<0.05).与B、A组比较,C组中bc1.2 mRNA水平增高不明显(P>0.05);治疗后72 h及7 d,bax与caspase.3 mRNA水平则明显降低(P<0.05). 结论 Kallikrein可能通过减少凋亡因子bax、caspase-3的表达,抑制脑梗死周边区域的神经细胞凋亡,从而达到保护缺血神经细胞,改善神经功能的作用.     

疏血通对局灶性脑缺血大鼠神经保护和hsp70表达水平的影响

目的 探讨疏血通对脑缺血-再灌注后神经保护作用的机制,拟为临床应用提供理论依据.方法 90只健康雄性SD大鼠,随机分为假手术组、缺血-再灌注组和疏血通治疗组,建立大脑中动脉闭塞模型.采用神经功能缺损评分对人鼠神经功能缺损程度进行评价,HE染色、TUNEL染色和免疫组织化学染色检测大鼠脑组织梗死灶体积、细胞凋亡及hsp70表达水平.结果 经疏血通治疗后,大鼠神经功能缺损程度明显改善,除再灌注后6h,其余各时间点疏血通治疗组评分均优于缺血-再灌注组(P<0.05).疏血通治疗组大鼠梗死灶体积明显缩小(P<0.01).再灌注后6 h,缺血半暗带区和海马区即可见凋亡细胞,分别于再灌注后48 h和72 h达峰值水平,疏血通治疗组表达高峰时间延迟,且各时间点凋亡细胞数目均少于缺血-再灌注组(P<0.05).再灌注后6 h,缺血半暗带区和大脑皮质即可见少量hsp70表达阳性细胞,两组均于再灌注后24 h达峰值水平,但疏血通治疗组各时间点hsp表达水平均高于缺血-再灌注组(P<0.05).结论 疏血通通过上调脑组织hsp70表达水平,减轻脑缺血-再灌注损伤,从而使梗死灶体积缩小、神经功能改善.     

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.