携带cdc2-siRNA的重组腺相关病毒对C型尼曼-皮克病小鼠行为学的影响

目的观察携带cdc2～小干扰RNA（cdc2-siRNA）的重组腺相关病毒（rAAV）小脑注射对C型尼曼-皮克病（NPC）小鼠行为学的影响。方法2周龄npc^-/-小鼠经小脑注射携带cdc2-siRNA的rAAV，动态测量小鼠体重，并进行衣架悬挂实验及足印实验评估小鼠4～8周的运动能力。结果（1）cdc2-siRNA组小鼠体重减轻明显延缓；（2）衣架悬挂实验显示cdc2-siRNA组小鼠运动缺陷明显改善；（3）足印实验显示cdc2-siRNA组相对步距[（75．1±8．6）％]与对照病毒组及非手术组相比明显增加。结论小脑注射携带cdc2-siRNA的rAAV改善了npc^-/-小鼠的行为学，有可能为NPC的治疗提供新的有效途径。     

抑制细胞周期依赖性蛋白激酶-5表达对C型尼曼-皮克病小鼠的神经保护作用

目的:观察抑制细胞周期依赖性蛋白激酶-5(cdk5)的表达对C型尼曼-皮克病(NPC)小鼠(npc-/-)的治疗作用。方法:采用携带cdk5特异性小干扰RNA(cdk5-siRNA)的重组腺相关病毒rAAV-cdk5-siRNA-GFP,对出生三天内的npc-/-小鼠进行双侧侧脑室注射,以rAAV-GFP注射组及非手术的同龄npc小鼠为对照(n=6～10/组);采用免疫组织化学染色、HE染色和小鼠衣架悬挂试验来评价小鼠脑内的神经病理改变和运动功能。结果:rAAV2-cdk5-siR-NA-GFP能显著减少轴突球状体的数量,延缓浦肯野细胞的死亡并改善npc-/-小鼠的运动功能。结论:降低cdk5的活性对npc-/-小鼠的神经元有一定的保护作用。     

激光散斑成像法监测格列本脲对小鼠SAH后脑微循环的影响

目的 探讨格列本脲对小鼠蛛网膜下腔出血（SAH）后脑微循环的影响。方法 将28只雄性C57小鼠随机分为对照组（n=6）、SAH组（n=6）、溶媒组（n=6）和格列本脲组（n=10）。视交叉前池注入自体非抗凝尾动脉血60 μl建立SAH模型。小鼠SAH后5 min内，格列本脲组腹腔注射格列本脲（25 μg/kg），溶媒组腹腔注射等体积二甲基亚砜；SAH组未进行任何治疗。造模后12 h，应用Garcia量表评分评估神经功能；造模前后使用激光散斑血流成像监测脑皮层灌注以及体感刺激下感觉皮层血流响应幅度。结果 造模后12 h，SAH组、溶媒组神经功能评分明显下降（P<0.05），脑感觉皮层灌注明显下降（P<0.05），体感刺激下感觉皮层血流响应幅度明显下降（P<0.05）。应用格列本脲后，小鼠神经功能评分明显增高（P<0.05），脑感觉皮层血流响应幅度和感觉皮层灌注明显改善（P<0.05）。结论 格列本脲可以改善小鼠SAH后神经功能，可能与改善脑微循环有关     

电针刺激预处理对C57BL6小鼠前脑缺血的保护作用研究

目的探讨电针刺激预处理是否对C57BL6小鼠前脑缺血具有保护效应。方法雄性C57BL6小鼠20只,18～20g,随机分为2组（n=10）：对照组行单纯缺血再灌注,即阻闭双侧颈总动脉（BCCAO）20min后进行再灌注;电针组接受电针刺激预处理百会穴30min,连续5d,最后一次预处理后24h接受BCCAO20min。再灌注24h后对所有动物进行神经功能评分并取脑行HE染色。结果再灌注24h,电针刺激预处理组动物神经功能评分显著优于对照组（P〈0.05）,电针刺激预处理组动物海马CA1区坏死神经元数量明显少于对照组（P〈0.05）。结论电针刺激预处理对C57BL6小鼠前脑缺血再灌注损伤具有保护作用。     

TLR4基因突变对小鼠坐骨神经损伤修复的影响

目的 探讨Toll样受体4（TLR4）基因突变达对小鼠坐骨神经损伤修复的影响。方法 取10只C3H/HeJ小鼠（TLR4基因突变作为突变组,20只C3H/HeN小鼠（TLR4基因正常）随机分为假手术组（n=10）和模型组（n=10）。突变组和模型组在暴露的坐骨神经中部用止血钳夹持60 s以建立小鼠坐骨神经损伤模型,假手术组仅暴露坐骨神经而不进行夹伤。造模后4周,采用坐骨神经功能指数（SFI）评分评定坐骨神经功能,然后每组取3只小鼠行HE染色观察坐骨神经病理改变,每组取3只小鼠采用RT-PCR检测坐骨神经组织白细胞介素-1β（IL-1β）、肿瘤坏死因子-α（TNF-α）、白细胞介素-6（IL-6）mRNA表达水平,每组取4只小鼠采用免疫印迹法检测坐骨神经组织生长相关蛋白43（GAP43）、p75神经营养素受体（p75NTR）蛋白表达水平。结果 与假手术组相比,模型组SFI评分显著降低（P<0.05）,HE染色显示细胞形态异常并出现大量嗜中性粒细胞和巨噬细胞,坐骨神经组织IL-1β、IL-6、TNF-α mRNA表达水平以及GAP43、p75NTR蛋白表达水平均显著增高（P<0.05）。与模型组相比,突变组SFI评分明显增高（P<0.05）,组织结构病理改变明显改善,IL-1β、IL-6、TNF-α mRNA表达水平以及GAP43、p75NTR蛋白表达水平显著降低（P<0.05）。结论 TLR4基因突变可促进小鼠坐骨神经损伤后修复,可能与降低IL-1β、IL-6、TNF-α等炎症因子水平有关。     

缺血性卒中无复流动物模型建立和多维度评价方案

目的 建立脑无复流模型并对灌注减低进行多维度评价。方法 利用激光散斑对比成像和双光子活体成像,比较C57BL/6(n=16)和BALB/c小鼠（n=37）短暂性大脑中动脉闭塞,以及BALB/c小鼠缺血1h或1.5h灌注改变情况。结合激光散斑对比成像、低倍率和较高放大倍率的灌注脑片图像,以及双光子显微镜监测红细胞流速和流量对短暂性大脑中动脉闭塞后脑灌注下降进行活体动态以及全脑切片和微血管的评估。用微管相关蛋白2染色和行为学评分评估梗死面积和行为学缺损。结果 在C57BL/6小鼠中,大脑中动脉区域大多数毛细血管在缺血期间仍然流动,而在BALB/c小鼠中,大多数毛细血管被阻断。此外,BALB/c小鼠缺血1.5 h后,24 h后再通时的皮质灌注减少至基线76.1%（与BALB/c sham组89.0%相比减少,P=0.046）,而缺血1 h减少至79.9%,与BALB/c sham组无明显差异（P=0.299）。切片全脑灌注评估BALB/c小鼠短暂性大脑中动脉闭塞1.5 h导致全脑灌注减少至75.1%（与BALB/c sham组100%相比降低,P<0.001）,双光子活体成像评估大脑中...     

实验性自身免疫性脑脊髓炎小鼠脑组织和脊髓中脑型肌酸激酶、钙泵和钙中性蛋白酶的变化

目的：观察实验性自身免疫性脑脊髓炎（EAE）小鼠模型脑组织和脊髓中脑型肌酸激酶（CK-BB）、钙泵（CaATPase）和钙中性蛋白酶（calpain）的变化。方法：C57BL/6小鼠随机分为：EAE组（n=9）,用髓鞘少突胶质细胞糖蛋白35-55多肽（MOG35-55）及完全弗氏佐剂混合抗原乳剂免疫小鼠;对照组（n=5）,注射生理盐水。用MOG35-55诱导C57BL/6小鼠,建立（EAE）动物模型（即多发性硬化模型）。观察记录EAE小鼠行为学变化;采用苏木精-伊红染色、LFB髓鞘染色,酶标仪和分光光度计法检测发病高峰期（免疫后第19天）的中枢神经组织病理学变化、CK-BB,CaATPase和calpain酶活性的改变。结果：EAE组与对照组相比：①日均神经功能评分和日累积评分增加（P〈0.01）;②苏木精-伊红染色：中枢炎症细胞浸润明显（P〈0.05）;③LFB染色：髓鞘脱失较多;④CK-BB和CaATPase活性降低,calpain活性增加（P〈0.05）;⑤EAE组小鼠（只）日均累积神经功能评分与CK-BB和CaATPase活性呈负相关（P〈0.05）;⑥EAE组小鼠（只）日均累积神经功能评分与calpain酶活性呈正相关（P〈0.05）。结论：EAE高峰期中枢CK-BB和CaATPase活性降低、calpain活性增高是EAE发生发展的后果,提示EAE时中枢能量代谢和CaATPase、calpain的病理性损害。     

IGF-1对大鼠局灶性脑损伤c—los表达的影响

目的研究胰岛素样生长因子-1（IGF-1）对大鼠局灶性脑缺血再灌注后c-los表达的影响及与缺血时间关系，探讨IGF-1对脑缺血再灌注损伤的保护作用。方法制作SD大鼠大脑中动脉缺血再灌注模型。将55只SD雄性大鼠随机分为假手术组（n=5）、对照组（n=25）、IGF-1治疗组（n=25），其中后2组按缺血再灌时间（6h、12h、1d、3d、7d）不同可分为5个亚组，每组5只，治疗组于缺血2h再灌注1h后经腹腔注入40μg／kg稀释为1ml的IGF-1，假手术组及对照组同时腹腔注入生理盐水1ml。以上动物均在再灌注后规定时间点用4％多聚甲醛经心脏灌注固定，取大鼠脑组织，应用免疫组化S-P法和HE染色检测c-fos蛋白表达及脑组织结构病理变化。结果与对照组相比，治疗组大鼠脑组织c-fos表达明显减少，神经细胞坏死程度明显减轻。结论IGF-1在大鼠局灶性脑缺血再灌注损伤中起保护作用，其作用机制包括降低c-fos的表达，发挥神经保护作用。     

bFGF对大鼠局灶性缺血再灌注脑组织HSP-70蛋白表达的影响

目的探讨大鼠脑缺血再灌注损伤后碱性成纤维细胞生长因子（bFGF）对热休克蛋白70表达的影响及其与神经细胞凋亡的关系。方法 SD大鼠24只,随机分为假手术组（n=8）、缺血再灌注组（n=8）和bFGF组（n=8）。应用线栓法制作大鼠局灶性脑缺血再灌注模型,大脑中动脉阻塞1 h再灌注24 h,bFGF组缺血即刻一次性经腹腔注射bFGF（10μg/kg）,假手术组和缺血再灌注组以相同方法给予0.9%的生理盐水。术后行免疫组织化学染色检测半胱氨酸天冬氨酸蛋白酶-3和热休克蛋白70的表达;原位末端标记法（TUNEL）检测神经细胞凋亡。结果热休克蛋白70蛋白的表达在bFGF组较缺血再灌注组明显增加（P〈0.05）;bFGF组半胱氨酸天冬氨酸蛋白酶-3的表达和神经细胞凋亡均较损伤组明显减少（P〈0.01,P〈0.05）。结论 bFGF能抑制大鼠脑缺血再灌注损伤后半胱氨酸天冬氨酸蛋白酶-3的活性,减轻神经细胞凋亡,其机制可能与诱导热休克蛋白70表达增加有关。     

亚低温对大鼠脑缺血再灌注损伤的保护研究

目的观察亚低温对大鼠全脑缺血再灌注后海马CAI区神经元凋亡的影响,探讨亚低温对缺血再灌注脑损伤的保护作用。方法SD大鼠30只随机分为对照组（n=10）,常温缺血组（n=10）,亚低温组（n=10）,采用改良的Pulsinelli-Brierley4血管法建立全脑缺血再灌注动物模型,缺血30min后再灌注72h,尼氏体染色观察海马区存活锥体细胞数,TUNEL法检测缺血后海马CAI区神经元凋亡情况,电镜下观察神经细胞形态学改变。结果与对照组比较,常温缺血组的海马CAI区存活的锥体细胞数目减少（P〈0.01）;与常温缺血组比较,亚低温组海马CAI存活的锥体细胞数目明显增多（P〈0.01）。对照组、亚低温组的海马CAI区神经元凋亡数目和凋亡指数明显低于常温缺血组。在电镜下观察亚低温能明显减轻缺血后脑组织病理形态学的损害程度。结论亚低温可以抑制脑缺血再灌注后的神经细胞凋亡,对神经细胞有保护作用。     

Experimental study of pharmacological hypothermia: enhanced neuroprotective effect of a novel 5-HT 1 A agonist SUN N4057 by the pharmacological hypothermia]

PURPOSE: 5-hydroxytryptamine(5-HT) 1 A receptor agonists have a potentially marked neuroprotective reaction by both neuroprotective and hypothermic effects. We previously reported (1) the neuroprotective effect against the cerebral ischemia under normothermic condition, and (2) the hypothermic effect of the novel compound of 5-HT 1 A agonist, SUN N4057. The present investigation was designed to examine the enhancement of the neuroprotective effect by its pharmacological hypothermia. METHODS: In 24 anesthetized cats(body weight 1.9-4.6 kg), the left middle cerebral artery(MCA) occlusion was performed via the transorbital approach. Just after MCA occlusion, SUN N4057(6 micrograms/kg/min) was infused. Physiological parameters were measured continuously, and arterial blood gas was analyzed hourly for 6 hours and maintained within the normal ranges. Animals were randomly allocated to the following three groups: (1) ischemic controls infused with sterile saline(Group A, n = 8), (2) SUN N4057 under normothermic condition(Group B, n = 8), (3) SUN N4057 (Group C, n = 8). Then, brain coronal sections of 3 mm in thickness were stained with 1% triphenyltetrazolium chloride(TTC) solution, and hemispheric infarct volumes were calculated by using a computerized image analysis system. RESULTS: There were no significant differences in any physiological parameters among 3 groups. In Group C, brain temperature decreased significantly starting 1 hour after MCA occlusion and dropped by 2.1 +/- 0.7 degrees C 5 hours. Infarct volumes were 35.6 +/- 6.9% (Group A), 23.3 +/- 5.8% (Group B) and 12.3 +/- 11.3% (Group C), respectively. There were significant differences among three groups(p < 0.05). CONCLUSION: On the basis of these data, we conclude that SUN N4057 provides more effective neuroprotection by the combination of hypothermic and neuroprotective effects. Chemical hypothermia may lead to a new therapeutic approaches for treatment of brain ischemia.     

Selective neurodegeneration, without neurofibrillary tangles, in a mouse model of Niemann-Pick C disease

The BALB/c mouse model of Niemann-Pick type C (NPC) disease exhibits neuropathological similarities to the human condition. There is an age-related cerebral atrophy, demyelination of the corpus callosum, and degeneration of cerebellar Purkinje cells in the NPC mouse. In human NPC, many cortical and subcortical neurons contain neurofibrillary tangles, which are thought by some investigators to play an important role in the neurodegenerative process. The purpose of the present study was to determine whether neurodegeneration occurs in the NPC mouse, in brain regions other than the cerebellum and whether the degeneration is related to the presence of neurofibrillary tangles. Using light microscopic methods with immunohistochemistry, electron microscopy, and cell counting methods, 11-week-old NPC(+/+) and NPC(-/-) animals were examined. In the NPC(-/-) mice, there were 96% fewer Purkinje cells, 28% fewer neurons in the prefrontal cortex, 20% fewer neurons in the thalamus, and 63% fewer glial cells in the corpus callosum. On the other hand, previous studies indicate normal numbers of neurons and glial cells in these same neuroanatomical regions in young NPC(-/-) mice. There were normal numbers of cholinergic neurons in sections assessed in the striatum and basal forebrain in the 11-week-old animals and no evidence of neurofibrillary tangles within cells. The present data indicate that both neurons and glial cells die in the NPC mouse but that all cells are not equally vulnerable. There was no evidence for neurofibrillary tangles in the NPC mouse, and therefore the degenerative process in the mouse is unrelated to the neurofibrillary tangle.     

CR8, a Selective and Potent CDK Inhibitor,Provides Neuroprotection in Experimental Traumatic Brain Injury

Traumatic brain injury (TBI) induces secondary injury mechanisms, including cell cycle activation (CCA), that leads to neuronal death and neurological dysfunction. We recently reported that delayed administration of roscovitine, a relatively selective cyclin-dependent kinase (CDK) inhibitor, inhibits CCA and attenuates neurodegeneration and functional deficits following controlled cortical impact (CCI) injury in mice. Here we evaluated the neuroprotective potential of CR8, a more potent second-generation roscovitine analog, using the mouse CCI model. Key CCA markers (cyclin A and B1) were significantly up-regulated in the injured cortex following TBI, and phosphorylation of CDK substrates was increased. Central administration of CR8 after TBI, at a dose 20 times less than previously required for roscovitine, attenuated CCA pathways and reduced post-traumatic apoptotic cell death at 24 h post-TBI. Central administration of CR8, at 3 h after TBI, significantly attenuated sensorimotor and cognitive deficits, decreased lesion volume, and improved neuronal survival in the cortex and dentate gyrus. Moreover, unlike roscovitine treatment in the same model, CR8 also attenuated post-traumatic neurodegeneration in the CA3 region of the hippocampus and thalamus at 21 days. Furthermore, delayed systemic administration of CR8, at a dose 10 times less than previously required for roscovitine, significantly improved cognitive performance after CCI. These findings further demonstrate the neuroprotective potential of cell cycle inhibitors following experimental TBI. Given the increased potency and efficacy of CR8 as compared to earlier purine analog types of CDK inhibitors, this drug should be considered as a candidate for future clinical trials of TBI.

Electronic supplementary material

The online version of this article (doi:10.1007/s13311-011-0095-4) contains supplementary material, which is available to authorized users.     

川芎嗪对MPTP所致小鼠多巴胺能神经元损伤的保护作用及机制

目的 探讨川芎嗪对MPTP所致小鼠多巴胺能神经元损伤的保护作用及可能机制.方法 C57BL/6J雄性小鼠32只,随机分为4组:生理盐水对照组(NS+NS)、生理盐水组(NS+MPTP)、川芎嗪高剂量组(LT50+MPTP)、川芎嗪低剂量组(LT20+MPTP),每组8只动物.分别采用HPLC法检测纹状体中DA的含量,免疫组化检测黑质中TH阳性细胞数,荧光显色法检测黑质SOD活力、GSH含量.结果 LT50+MPTP组纹状体DA含量、黑质DA神经元数量、黑质SOD活力、黑质GSH含量较NS+MPTP组显著增高(P<0.01).结论 川芎嗪对对MPTP所致的小鼠多巴胺能神经元损伤具有保护作用,其保护机制可能与其调节调节小鼠黑质中的SOD、GSH含量有关.

Abstract：

Objective To investigate the neuroprotective effects and mechanisms of ligustrazine on the MPTP-in-duced dopaminergic neurodegeneration in a mouse model of PD. Methods Male C57BL/6J mice were randomly divided into following four treatment groups ( n = 8/group) : ( 1 ) the saline control group ( NS + NS), mice pretreated with saline followed by saline treatment;(2) the mice pre-treated with saline followed by saline treatment (NS + MPTP) ; (3) the mice pretreated with 50mg/kg of ligustrazine followed by MPTP treatment (LT50 + MPTP) ;(4) the mice pretreated with 20mg/kg of ligustrazine followed by MPTP ( LT20 + MPTP). HPLC,immunohistochemistry and fluorimetry were used. Results The residual DA contents, TH-IR positive cells, SOD activity and GSH content in the mice pretreated with 50mg/kg ligustrazine ( LT50 + MPTP) were significantly higher than those of the saline-pretreatd mice ( NS + MPTP) ( P < 0.01 ).Conclusions Ligustrazine ameliorated MPTP-induced dopaminergic neurodegeneration in mice. The neuroprotective effect of ligustrazine may be associated with their strong antioxidant capacity in vivo.     

CR8, a Selective and Potent CDK Inhibitor,Provides Neuroprotection in Experimental Traumatic Brain Injury

Traumatic brain injury (TBI) induces secondary injury mechanisms, including cell cycle activation (CCA), that leads to neuronal death and neurological dysfunction. We recently reported that delayed administration of roscovitine, a relatively selective cyclin-dependent kinase (CDK) inhibitor, inhibits CCA and attenuates neurodegeneration and functional deficits following controlled cortical impact (CCI) injury in mice. Here we evaluated the neuroprotective potential of CR8, a more potent second-generation roscovitine analog, using the mouse CCI model. Key CCA markers (cyclin A and B1) were significantly up-regulated in the injured cortex following TBI, and phosphorylation of CDK substrates was increased. Central administration of CR8 after TBI, at a dose 20 times less than previously required for roscovitine, attenuated CCA pathways and reduced post-traumatic apoptotic cell death at 24 h post-TBI. Central administration of CR8, at 3 h after TBI, significantly attenuated sensorimotor and cognitive deficits, decreased lesion volume, and improved neuronal survival in the cortex and dentate gyrus. Moreover, unlike roscovitine treatment in the same model, CR8 also attenuated post-traumatic neurodegeneration in the CA3 region of the hippocampus and thalamus at 21 days. Furthermore, delayed systemic administration of CR8, at a dose 10 times less than previously required for roscovitine, significantly improved cognitive performance after CCI. These findings further demonstrate the neuroprotective potential of cell cycle inhibitors following experimental TBI. Given the increased potency and efficacy of CR8 as compared to earlier purine analog types of CDK inhibitors, this drug should be considered as a candidate for future clinical trials of TBI.     

Evaluation of Nigrostriatal Neurodegeneration and Neuroinflammation Following Repeated Intranasal 1-Methyl-4-Phenyl-1,2,3,6-Tetrahydropyridine (MPTP) Administration in Mice, an Experimental Model of Parkinson’s Disease

Parkinson’s disease (PD) is the second most common neurodegenerative disorder affecting approximately 1 % of the population older than 60 years. The administration of the proneurotoxin 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) in mice is the most widely used approach to elucidate the mechanisms of cell death involved in PD. However, the magnitude of the PD-like neurodegeneration induced by MPTP depends on many variables, including the regimen of its administration. It has been demonstrated that intranasal (i.n.) administration of MPTP constitutes a new route of toxin delivery to the brain that mimics environmental exposure to neurotoxins. Previous data showed that mice submitted to chronic and acute i.n. MPTP treatment displayed a robust (~80 %) and moderate (~55 %) loss of striatal dopamine, respectively. However, little is known about the neurodegenerative and neuroinflammatory processes following a subacute i.n. MPTP administration in mice. Here, the C57BL/6 mice were infused intranasally with MPTP (1 mg/nostril/day) during 4 consecutive days. At 7 and 28 days after the last administration, the subacute i.n. MPTP regime decreased the tyrosine hydroxylase (TH)-labeling in the striatum (40–50 %) and substantia nigra (25–30 %) and increased the astrogliosis in such brain areas at both time points. Taken together, our data showed that the subacute administration of MPTP into the nasal cavity of C57BL/6 mice induces long-lasting neurodegeneration and neuroinflammation in the nigrostriatal pathway, thus representing a valuable animal model for the investigation of neuroprotective strategies in PD.     

粒细胞集落刺激因子对脑卒中的神经保护作用研究

目的:研究在脑梗塞后不同时间窗内应用粒细胞集落刺激因子(G-CSF)的神经保护作用。方法:中风模型采用线栓MCA法,栓塞后90min后再灌注;动物采用雄性Wistar大鼠(n=45,体重280～320g)。实验组大鼠分别在中风后30min(n=11)、24h(n=12)、48h(n=10)开始皮下注射G-CSF(60ug/kg．day),至第7日结束;对照组大鼠(n=12)应用生理盐水0．3ml/日。每日检测大鼠体重变化。中风后7天,取脑进行形态学研究,分别进行anti-MPA2和TUNEL染色,计算脑梗塞体积和梗塞灶周围神经细胞凋亡情况。结果:对照组脑梗塞体积(163±25mm~3)明显大于30min(81±19mm~3)、24h(98±27mm~3)[P＜0．001]及48h(114±23mm~3)[P＜0．01]等各治疗组。对照组TUNEL阳性细胞数(187±21)明显高于MCAO后30min及24h开始应用G-CSF的治疗组(P＜0．01)。结论:G-CSF有明显的脑保护作用,即使在脑梗塞发生候后48小时才开始应用,效果仍然明显。     

Estrogen is neuroprotective via an apolipoprotein E-dependent mechanism in a mouse model of global ischemia.

Estrogen can ameliorate brain damage in experimental models of focal cerebral ischemia., estrogen increases levels of apolipoprotein E (apoE), which also has neuroprotective effects in brain injury. The authors tested the hypotheses that physiologically relevant levels of 17beta-estradiol are neuroprotective in global cerebral ischemia and that neuroprotection is mediated via apoE. In the first study, subcutaneous implants of 17beta-estradiol were tested in female C57Bl/6J mice (ovariectomized and nonovariectomized) and plasma levels measured by radioimmunoassay to validate that physiologically relevant levels could be achieved. In the second study, female C57Bl/6J and apoE-deficient mice were ovariectomized and implanted with 17beta-estradiol or placebo pellet. Two weeks later, transient global ischemia was induced by bilateral carotid artery occlusion and the mice killed after 72 hours. Ischemic and normal neurons were counted in the caudate nucleus and CA1 pyramidal cell layer and the percentage of neuronal damage was compared between the treated groups. In C57Bl/6J mice, there was less neuronal damage in the 17beta-estradiol-treated group compared with placebo group in the caudate nucleus (15 +/- 20% versus 39 +/- 27%, = 0.02) and in the CA1 pyramidal cell layer (1.8 +/- 2% versus 10 +/- 14%, = 0.08). In contrast, neuronal damage was not significantly different between the 17beta-estradiol and placebo groups in apoE-deficient mice in the caudate nucleus (47 +/- 35% versus 53 +/- 29%, = 0.7) or in the CA1 pyramidal cell layer (24 +/- 19% versus 24 +/- 19%, = 1.0). The data indicate a neuroprotective role for estrogen in global ischemia, the mechanism of which is apoE-dependent.     

Allopregnanolone treatment, both as a single injection or repetitively, delays demyelination and enhances survival of Niemann-Pick C mice

Niemann-Pick C disease (NPC) is an irreversible neurodegenerative disorder without current treatment. It is thought to result from deficient intracellular cholesterol and/or ganglioside trafficking. We have investigated the effects of allopregnanolone treatments on survival, weight loss, motor function, magnetic resonance imaging (MRI), and neuropathology in the mouse model of NPC (Npc1(-/-) mice). We confirmed previous results showing that a single injection of 250 microg of allopregnanolone on postnatal day 7 significantly extended the life span of Npc1(-/-) mice. This caused a marked difference in the weight curves of the treated mice but no statistical difference in the Rota-Rod performance. T2-weighted MRI and diffusion tensor imaging (DTI) of treated mice showed values of signal intensity and fractional anisotropy closer to those of wild-type mice than those of untreated Npc1(-/-) mice. Neuropathology showed that day-7 treatment markedly suppressed astrocyte reaction and significantly reduced microglial activation. Furthermore, the steroid treatment also increased myelination in brains of Npc1(-/-) mice. Similar effects of allopregnanolone treatment were observed in Npc1(-/-), mdr1a(-/-) double-mutant mice, which have a deficient blood-brain barrier, resulting in increased steroid uptake. The effects on survival and weight loss of a single injection on day 7 followed by injections every 2 weeks were also evaluated in Npc1(-/-) mice, and the beneficial effects were found to be greater than with the single injection at day 7. We conclude that allopregnanolone treatment significantly ameliorates several symptoms of NPC in Npc1(-/-) mice, presumably by effects on myelination or neuronal connectivity.