美满霉素对沙鼠急性脑缺血后脑皮质钙视网膜蛋白表达的影响

目的:观察美满霉素对蒙古沙鼠短暂性脑缺血再灌后前额皮质中钙视网膜蛋白Calretinin(CR)表达的影响,为进一步研究其生理功能及治疗提供参考。方法:42只健康雄性蒙古沙鼠随机分为:正常组对照组、缺血再灌组,美满霉素治疗组。夹闭蒙古沙鼠双侧颈总动脉10 min诱导前脑缺血后,动物分别存活1天、3天或7天。用免疫组化方法检测前额皮质中CR的表达,用图像分析仪测定灰度值。结果:与正常组相比,缺血再灌组与美满霉素治疗组中前额皮质中CR表达均先减少后升高再下降。缺血再灌1天组,CR表达显著减少(P<0.05);3天组CR表达达到高峰(P<0.05);7天组CR表达减弱,但仍高于正常组(P<0.05)。美满霉素治疗各组中的CR表达均弱于对应的缺血再灌组(P<0.05)。结论:美满霉素能抑制蒙古沙鼠脑缺血再灌注后脑皮质中CR的表达来发挥脑保护作用。     

蒙古沙鼠脑缺血后大脑皮质Calretinin(CR)的表达变化

目的:观察蒙古沙鼠前脑短暂缺血后前额皮质Calretinin(CR)的表达变化,为进一步研究其功能及治疗提供形态学依据。方法:24只健康雄性长爪鼠随机分为正常组对照组(6只)和缺血组(18只),夹闭蒙古沙鼠双测颈总动脉10 min诱导前脑缺血后,动物分别存活1天、3天或7天。用免疫组织化学方法检测了前额皮质中CR的表达。结果:与正常组相比,各缺血组中前额皮质中CR表达均上调。缺血再灌1天时,CR表达最强(P＜0．01);3天时CR表达开始恢复(P＜0．05);7天时CR表达进一步恢复,但仍高于正常组(P＜0．01)。结论:前脑短暂缺血后可造成蒙古沙鼠前额皮质CR的表达在短时间内急剧上调;但随着时间的CR的表达会恢复正常。     

沙鼠脑缺血模型特点及应用的研究进展

脑缺血因其高的发病率而成为近年来研究的热点。用于研究脑缺血的动物模型较多,其中沙鼠因大脑基底动脉环先天性发育不完全而成为脑缺血研究的较理想模型。沙鼠脑缺血模型在研究单侧脑缺血和全脑缺血方面都具有独特的优势,在研究脑缺血后脑区的病理变化、再灌注损伤机制及开发脑保护药方面都得到十分广泛的应用。本文针对不同脑缺血模型尤其是沙鼠模型的制作方法、优缺点及应用领域,将近年来国内外相关研究文献进行较为系统的梳理和综述。     

长爪沙鼠脑缺血后大脑皮质Parvalbumin(PV)的表达变化

目的:观察长爪沙鼠大鼠前脑短暂缺血后前额皮质Parvalbumin(PV)的表达变化,为进一步研究其功能及其对脑缺血损伤的治疗作用提供形态学依据。方法:24只健康雄性长爪鼠随机分为时照组(6只)和缺血组(18只),夹闭长爪沙鼠双测颈总动脉10min诱导前脑缺血后,动物分别存活1天、3天或7天。用免疫组化方法、阳性细胞计数和相对平均灰度值检测了前额皮质中PV的表达情况。结果:与正常组相比,各缺血组中前额皮质中PV表达均减少。缺血再灌1天时,PV表达最弱(P＜0．01);3天时PV表达开始恢复(P＜0．05);7天时PV表达进一步恢复,但仍低于正常组(P＞0．05)。结论:前脑短暂缺血后可造成长爪沙鼠前额皮质PV的表达在短时间内急剧下降;但随着缺血消失后时间的延长,机体可进行部分的自行修复。     

川芎嗪对脑缺血再灌注皮质神经元生存素表达的影响

目的探讨川芎嗪对脑缺血再灌注皮质神经元生存素表达的影响。方法大鼠60只分为正常对照组、假手术组、模型组、川芎嗪治疗1组(小剂量)和治疗2组(大剂量)。采用Bannister s颈动脉血引流法复制大鼠脑缺血再灌注动物模型并用腹腔注射川芎嗪治疗。缺血90min后,再灌注2h、24h和72h分别处死大鼠。脑组织4%多聚甲醛固定,石蜡切片;SP免疫组织化学染色。结果正常对照组survivin阴性,假手术组偶见阳性细胞,模型组大脑皮质出现较多的survivin阳性神经元,治疗1、2组在2h、24h、72h组survivin阳性细胞数密度增高,着色深(灰度值低);明显高于模型组。结论川芎嗪对脑缺血再灌注神经元中生存素表达有上调作用,并有量效关系和时相变化。     

微卫星DNA与生化标记分析对长爪沙鼠群体遗传分析的比较

目的比较生化标记和微卫星DNA标记方法对长爪沙鼠群体遗传分析的可靠性。方法应用27个生化位点和13个微卫星DNA位点,采用已建立的生化标记和微卫星DNA标记分析方法对国内2个长爪沙鼠群体进行遗传分析,计算并比较两种方法测得的各群体遗传参数。结果生化基因位点中有13个位点在整体中呈现遗传多态性,多态率为48.1%;微卫星位点中有11个位点在整体中表现出多态性,多态率均为84.6%。两种方法测得的平均有效等位基因数趋于一致,微卫星DNA的多态位点百分率和平均杂合度均明显高于生化标记方法。但生化标记和微卫星DNA检测对两个长爪沙鼠群体的遗传多样性差异反映一致,所反映的群体平衡状况也基本一致。结论生化标记分析和微卫星DNA方法均可较好地反映长爪沙鼠群体遗传结构。     

长爪沙鼠脑底动脉Willis环变异缺失遗传特性分析及脑缺血模型高发群体的初步培育

目的研究长爪沙鼠脑底动脉Willis环遗传特性,并定向培育脑缺血高发种群。方法通过对5代定向培育的长爪沙鼠高发群动物共398只动物的右侧颈总动脉结扎模型进行观察,比较长爪沙鼠亲代与子代间脑底动脉Willis环的变异缺失类型,探求其遗传特性,并根据该遗传特性将Willis环后交通支缺失且前交通支缺失或细小的同类型的长爪沙鼠父母所生的子代雌雄个体配对繁殖,定向培育长爪沙鼠半脑缺血模型高发生率种群。结果当双亲的Willis环类型一致时,其子代大部分与其父母一致;而当双亲的Willis环类型不一致时,Willis环前交通支与母亲一致率为60.4%,前交通支与父亲的一致率为48.2%,两者的差异有显著性意义（P=0.015）。长爪沙鼠半脑缺血模型高发生率种群定向培育5代后,行单侧颈总动脉结扎时,一侧脑缺血造模成功率由F1代的40%提高到F5代的75%。结论长爪沙鼠脑底动脉Willis环变异有明显的遗传性,初步培育出了长爪沙鼠半脑缺血模型高发生率种群。     

人幽门螺杆菌蒙古沙鼠适应性定植相关蛋白表达差异的研究

幽门螺杆菌 (Helicobacterpylori,Hp)是人类慢性活动性胃炎和消化溃疡的重要原因 ,与胃癌和胃淋巴样组织淋巴瘤的发生也极度相关。目前人类对其生物学特点、致病机制及其与宿主的关系等方面均尚未完全阐明。随着对Hp在分子水平上的研究不断深入 ,人们发现Hp较其它细菌表现出更高的生物多样性 ,提示该菌面对复杂的定居环境 ,具有高度的变异性和独特的适应性机制。Hp全基因组测序工作的完成 ,为深入研究Hp提供了良好的条件 ,也为后续的蛋白质组学研究打下了坚实的基础。近几年 ,国内外研究者采用蛋白质组学技术相继在Hp的遗传变异、生理、…     

雌雄同居对子午沙鼠情绪及下丘脑催产素表达的影响

雌雄同居是配偶关系形成的重要阶段,涉及到一系列生理和情绪的变化,对长期稳定的配偶关系形成具有重要意义。然而由于单配制动物模型较少,雌雄同居过程中的神经调控,尤其是两性差异仍不清楚。本研究以室内繁殖的子午沙鼠(Meriones meridianus)为研究对象,采用高架十字迷宫、强迫游泳和免疫组化法,探究雌雄同居对雌雄子午沙鼠的情绪变化及其相关脑区催产素表达的影响。结果表明：雌雄同居10 d后,在高架十字迷宫中,雌性沙鼠进入开放臂的频次显著减少(P <0.05),焦虑指数显著升高(P <0.05);在强迫游泳实验中,同居组雌性沙鼠停止游泳的频次和时间显著增加(P <0.05);同居组雌性沙鼠在下丘脑室旁核和视上核中的催产素表达水平显著升高(P <0.05)。然而同居组雄性的行为和催产素水平均没有出现显著变化,这可能与雌雄配偶关系形成过程中的两性不同步有关。综上,雌雄同居仅使得雌性子午沙鼠表现出焦虑样行为,且下丘脑催产素系统可能参与了该过程。     

Mechanism of Arachidonic Acid Liberation During Ischemia in Gerbil Cerebral Cortex

Once brain ischemia was induced in the gerbil cerebral fronto-parietal cortex, serial changes occurred in energy metabolites and various lipids. The amounts of inositol-containing phospholipids began to decrease immediately after energy failure, followed by an increase in the amount of 1,2-diacylglycerol with a subsequent liberation of arachidonic acid and other free fatty acids. The fatty acid compositions of inositol-containing phospholipids, of 1,2-diacylglycerols produced by ischemia, and of free fatty acids liberated during ischemia were quite similar. The amount of stearic acid liberated was much larger than that of arachidonic acid between 30 s and 1 min of ischemia. On the other hand, there was no significant decrease in the amount of the other phospholipids except for phosphatidic acid. Furthermore, there was also no change in the fatty acid composition of phosphatidylcholine or phosphatidylethanolamine throughout 15 min of ischemia. The amount of cytidine-monophosphate reached a peak (36.7 nmol/g wet wt) at 2 min of ischemia. These results indicated that arachidonic acid was predominantly liberated from inositol-containing phospholipids by phospholipase C, and by the diglyceride lipase and monoglyceride lipase system rather than from phosphatidylcholine or phosphatidylethanolamine by phospholipase A2 or plasmalogenase or choline phosphotransferase during the early period of ischemia.     

Differential Effect of Cerebral Ischemia on Monoamine Content of Discrete Brain Regions of the Mongolian Gerbil (Meriones unguiculatus)

The effect of bilateral cerebral ischemia on noradrenaline, dopamine, and serotonin concentrations in six brain regions (i.e., the cerebral cortex, striatum, hippocampus, midbrain-diencephalon, cerebellum, and pons-medulla oblongata) was examined in the gerbil stroke model. The relative changes in regional cerebral blood flow after bilateral common carotid occlusion were also assessed using the radioactive microsphere technique. At 1 h after bilateral carotid occlusion, a significant decrease of monoamine concentration was observed in the cerebral cortex, striatum, hippocampus, and midbrain-diencephalon whereas no significant change was detected in the cerebellum and pons-medulla oblongata. The fall in NA content was most prominent in the cerebral cortex and hippocampus and percentage reductions of dopamine and serotonin were greatest in the striatum and cerebral cortex, respectively. These results suggest that the monoamine neurons in various brain regions might have different vulnerabilities to ischemic insult and show no evidence of transtentorial diaschisis.     

Acute Treatment with Docosahexaenoic Acid Complexed to Albumin Reduces Injury after a Permanent Focal Cerebral Ischemia in Rats

Docosahexaenoic acid complexed to albumin (DHA-Alb) is highly neuroprotective after temporary middle cerebral artery occlusion (MCAo), but whether a similar effect occurs in permanent MCAo is unknown. Male Sprague-Dawley rats (270–330 g) underwent permanent MCAo. Neurological function was evaluated on days 1, 2 and 3 after MCAo. We studied six groups: DHA (5 mg/kg), Alb (0.63 or 1.25 g/kg), DHA-Alb (5 mg/kg+0.63 g/kg or 5 mg/kg+1.25 g/kg) or saline. Treatment was administered i.v. at 3 h after onset of stroke (n = 7–10 per group). Ex vivo imaging of brains and histopathology were conducted on day 3. Saline- and Alb-treated rats developed severe neurological deficits but were not significantly different from one another. In contrast, rats treated with low and moderate doses of DHA-Alb showed improved neurological score compared to corresponding Alb groups on days 2 and 3. Total, cortical and subcortical lesion volumes computed from T2 weighted images were reduced following a moderate dose of DHA-Alb (1.25 g/kg) by 25%, 22%, 34%, respectively, compared to the Alb group. The total corrected, cortical and subcortical infarct volumes were reduced by low (by 36–40%) and moderate doses (by 34–42%) of DHA-Alb treatment compared to the Alb groups. In conclusion, DHA-Alb therapy is highly neuroprotective in permanent MCAo in rats. This treatment can provide the basis for future therapeutics for patients suffering from ischemic stroke.     

Effects of Transient Cerebral Ischemia on the Expression of DNA Methyltransferase 1 in the Gerbil Hippocampal CA1 Region

DNA methylation is a key epigenetic modification of DNA that is catalyzed by DNA methyltransferases (Dnmt). Increasing evidences suggest that DNA methylation in neurons regulates synaptic plasticity as well as neuronal network activity. In the present study, we investigated the changes in DNA methyltransferases 1 (Dnmt1) immunoreactivity and its protein levels in the gerbil hippocampal CA1 region after 5 min of transient global cerebral ischemia. CA1 pyramidal neurons were well stained with NeuN (a neuron-specific soluble nuclear antigen) antibody in the sham-group, Four days after ischemia–reperfusion (I–R), NeuN-positive (⁺) cells were significantly decreased in the stratum pyramidale (SP) of the CA1 region, and many Fluro-Jade B (a marker for neuronal degeneration)⁺ cells were observed in the SP. Dnmt1 immunoreactivity was well detected in all the layers of the sham-group. Dnmt1 immunoreactivity was hardly detected only in the stratum pyramidale of the CA1 region from 4 days post-ischemia; however, at these times, Dnmt1 immunoreactivity was newly expressed in GABAergic interneurons or astrocytes in the ischemic CA1 region. In addition, the level of Dnmt1 was lowest at 4 days post-ischemia. In brief, both the Dnmt1 immunoreactivity and protein levels were distinctively decreased in the ischemic CA1 region 4 days after transient cerebral ischemia. These results indicate that the decrease of Dnmt1 expression at 4 days post-ischemia may be related to ischemia-induced delayed neuronal death.     

GnRH—a对大鼠海马和皮质部位parvalbumin表达的影响

目的：研究促性腺激素释放激素类似物（gonadotropin releasing hormone analogue,GnRH-a）对大鼠海马、皮质部位小白蛋白（parvalbumin,PV）表达的影响。方法：采用酶联免疫吸附试验测定血清激素水平,免疫组织化学和图像分析观察大鼠海马、皮质部位PV的表达。结果：①GnRH-a组大鼠血清雌二醇（estradiol,E2）、LH及FSH水平较正常对照组下降,差异有统计学意义（P〈0.05）;与OVX组比较LH、FSH较低,差异有统计学意义（P〈0.05）,但E2差异不显著。②正常情况下,大鼠海马、皮质部位可观察到PV神经元及纤维分布。③GnRH-a组PV细胞数及灰度值低于正常对照组,差异有统计学意义（P〈0.05）,与去卵巢组大鼠组相似;GnRH-a＋E2联合用药后,PV细胞数及灰度值与正常对照组相似。结论：GnRH-a降低大鼠海马、皮质部位神经元中PV的表达,从而影响神经元的功能,这可能与其用药后神经精神副反应有一定关系。