人参皂甙Rd抑制大鼠局灶性脑缺血后趋化因子CXCL1和γ-干扰素的蛋白表达

目的：研究人参皂甙Rd（Ginsenoside-Rd,GS-Rd）在大鼠局灶性脑缺血后对炎症趋化因子CXCL1和γ-干扰素（Interferon-γ,IFN-γ）的影响。方法：将SD大鼠随机分为5组：正常组（n=5）,假手术组（n=5）,GS-Rd对照组（n=5）,大脑中动脉栓塞模型（MCAO）组（n=20）,MCAO＋GS-Rd组（n=20）。正常组不做任何处理;假手术组进行大脑中动脉栓塞手术,但不插入栓线;GS-Rd对照组给予腹腔注射10 mg/Kg GS-Rd,不进行手术;MCAO组（n=20）和MCAO＋GS-Rd组（n=20）进行大脑中动脉栓塞手术,术后2小时拔出栓线,MCAO＋GS-Rd组在术前15分钟腹腔注射10 mg/Kg GS-Rd。在12小时、1天、3天、7天四个时间点分别提取脑组织蛋白,通过液相芯片技术检测CXCL1,IFN-γ含量。结果：正常组,假手术组和GS-Rd对照组组间CXCL1,IFN-γ含量无统计学差异;与三个对照组相比,MCAO组和MCAO＋GS-Rd组中CXCL1,IFN-γ蛋白含量均有明显增加（P〈0.05）;而与MCAO组相比,MCAO＋GS-Rd组CXCL1,IFN-γ的生成明显减少（P〈0.05）。结论：10 mg/Kg GS-Rd预处理可有效抑制大鼠短暂性脑缺血后CXCL1,IFN-γ的生成;通过抑制炎症反应,GS-Rd可能在神经保护中发挥重要的作用。     

人参皂甙Rd通过调节SNI大鼠背根神经节钠、钾电流抑制痛敏

目的：观察人参皂甙Rd（ginsenoside Rd）对大鼠坐骨神经分支选择性损伤（spared sciatic nerve injury,SNI）引起的痛敏的影响及其作用机制。方法：坐骨神经分支选择性损伤术后7天,观察腹腔注射不同浓度人参皂甙Rd后大鼠后足的机械性缩足反应阈值（paw withdrawl mechanical threshold,PWMT）的变化;在术后7天,急性分离并取出大鼠腰4和腰5段背根节,对整节DRG上的中小型神经元运用全细胞膜片钳技术进行记录。结果：坐骨神经分支选择性损伤术后7天,大鼠出现明显的机械性痛敏,腹腔注射5 mg/ml和10 mg/ml的人参皂甙Rd能剂量依赖性的翻转大鼠机械性痛敏;坐骨神经分支选择性损伤能明显地增大SNI大鼠DRG中小型神经元上的钠电流以及减小电压依赖性钾电流,而100μM人参皂甙Rd能有效翻转该钠、钾电流的变化。结论：人参皂甙Rd能有效地改善坐骨神经分支选择性损伤引起的机械性痛敏,其机制可能与人参皂甙Rd明显地调节SNI大鼠DRG中小型神经元上的电压依赖性钠、钾电流有关。     

人参皂甙Rd通过调节SNI大鼠背根神经节钠、钾电流抑制痛敏

目的:观察人参皂甙Rd(ginsenoside Rd)对大鼠坐骨神经分支选择性损伤(spared sciatic nerve injury,SNI)引起的痛敏的影响及其作用机制。方法:坐骨神经分支选择性损伤术后7天,观察腹腔注射不同浓度人参皂甙Rd后大鼠后足的机械性缩足反应阈值(paw withdrawl mechanical threshold,PWMT)的变化;在术后7天,急性分离并取出大鼠腰4和腰5段背根节,对整节DRG上的中小型神经元运用全细胞膜片钳技术进行记录。结果:坐骨神经分支选择性损伤术后7天,大鼠出现明显的机械性痛敏,腹腔注射5 mg/ml和10 mg/ml的人参皂甙Rd能剂量依赖性的翻转大鼠机械性痛敏;坐骨神经分支选择性损伤能明显地增大SNI大鼠DRG中小型神经元上的钠电流以及减小电压依赖性钾电流,而100μM人参皂甙Rd能有效翻转该钠、钾电流的变化。结论:人参皂甙Rd能有效地改善坐骨神经分支选择性损伤引起的机械性痛敏,其机制可能与人参皂甙Rd明显地调节SNI大鼠DRG中小型神经元上的电压依赖性钠、钾电流有关。     

人参皂甙Rb1对阿尔茨海默病大鼠海马结构β-淀粉样蛋白表达的影响

目的观察人参皂甙Rb1对阿尔茨海默病（AD）模型大鼠学习记忆能力及海马结构β-淀粉样蛋白表达的影响。方法动物分3组：对照组、模型组及治疗组,用D半乳糖联合三氯化铝建立AD大鼠模型,治疗组在造模后给予人参皂甙Rb1腹腔注射4周;采用Morris水迷宫测试大鼠的空间学习记忆能力,用免疫组织化学方法观察海马结构β-淀粉样蛋白的表达。结果与对照组相比,模型组大鼠各时间段的逃避潜伏期均显著延长（P〈0．01）,海马CA1、CA3区及齿状回β-淀粉样蛋白表达的阳性细胞数明显增多（P〈0．01）;治疗组大鼠的逃避潜伏期较模型组明显缩短（P〈0．01）,海马CA1、CA3区及齿状回的β-淀粉样蛋白阳性细胞数显著减少（P〈0．01）。结论人参皂甙Rb1对AD模型大鼠学习记忆损害具有明显改善作用,其机制可能与人参皂甙Rb1减少海马结构β-淀粉样蛋白的表达有关。     

人参皂甙Rg1对脑缺血再灌注大鼠脑组织Bax和Bcl-2蛋白表达的影响

目的探讨人参皂甙Rg1对脑缺血再灌注大鼠脑组织Bcl-2和Bax表达的影响及其意义。方法分别给大鼠腹腔注射人参皂甙Rg1 10、20、40 mg/kg,采用大脑中动脉闭塞方法建立脑缺血再灌注模型,观察大鼠脑缺血再灌注后不同时间段（2 h、24 h）神经功能缺损评分;应用免疫组化法检测脑组织缺血再灌注24h后Bcl-2、Bax的表达。结果人参皂甙Rg1组大鼠脑缺血后各时间点神经功能缺损评分显著低于单纯缺血再灌注组（P〈0.05）;与单纯缺血再灌注组相比,人参皂甙Rg1各组Bcl-2表达显著增高,Bax表达显著降低,Bcl-2/Bax比值显著上调（P〈0.05）。结论人参皂甙Rg1防治大鼠脑缺血再灌注损伤的机制可能与促进脑组织Bcl-2表达、抑制Bax表达有关,且以高剂量效果较好。     

人参皂甙Rb1对大鼠脑缺血再灌注神经损伤后的修复作用

通过阻塞大鼠大脑动脉,制备短暂性脑缺血大鼠模型,将出现神经功能缺失症状的大鼠随机分组,实施再灌注后立即按(40mg/kg)进行腹腔注射人参皂甙Rb1。结果发现大鼠脑缺血再灌注后,人参皂甙Rb1通过促进NAIP、Bcl-2表达和抑制Bax表达发挥神经损伤后的修复作用。人参皂甙Rb1给药组在各时间点的胶质细胞源性神经营养因子(GDNF)阳性细胞数远远高于单纯脑缺血再灌注组(P<0.01)。GDNF的表达与缺血性损伤有一定的联系,可认为人参皂甙Rbl对神经系统有一定保护作用。     

人参皂甙Rb1抑制扩张型心肌病发生中的HB-EGF表达和纤维化

目的HB-EGF过表达可促进心肌纤维化及心肌细胞凋亡,本文研究人参皂甙Rb1对cTnT^R141W转基因扩张型心肌病小鼠发病过程中的HB-EGF表达和心肌纤维化的影响。方法将cTnT^R141W转基因小鼠随机分为模型组和人参皂甙Rb1组（70 mg/kg/d）,连续给药7个月,取野生型小鼠作为对照组。用Kaplan-Meier法进行生存分析。心脏超声检测心功能及心脏几何构型。计算心重指数。光镜观察心肌细胞及间质变化。Western blot检测心脏HB-EGF,pSTAT3表达水平。结果Rb1长期给药能显著改善该模型的心功能和心脏几何构型,将死亡率降低50%。Rb1治疗组心重指数降低11.3%（P〈0.05）,光镜观察显示Rb1能减轻心肌细胞排列紊乱以及间质纤维化。Western blot结果显示Rb1能够显著降低模型中的HB-EGF及pSTAT3的表达。结论Rb1抑制心肌病发生中的HB-EGF表达及抑制下游信号pSTAT的激活,并改善扩张型心肌病模型的心功能及心脏重构。     

人参皂甙Rb1对AD大鼠顶叶皮质β-分泌酶及PS-1表达的影响

目的探讨人参皂甙Rb1对AD大鼠顶叶皮质β-分泌酶及PS-1表达的影响。方法30只健康雄性SD大鼠,随机分为对照组、模型组和治疗组。模型组大鼠胃饲氯化铝同时腹腔注射D半乳糖2个月,对照组大鼠给予等剂量生理盐水,治疗组大鼠于造模结束后腹腔注射人参皂甙Rb14周。采用刚果红染色法观察老年斑,镀银染色法观察神经原纤维缠结,Western blot方法、免疫组化方法和图像分析技术对β-分泌酶及PS-1的表达进行检测。结果模型组与对照组相比有明显的老年斑及神经原纤维缠结形成,β-分泌酶及PS-1的表达增多（P〈0．01）;治疗组老年斑及神经原纤维缠结数量减少,β-分泌酶及PS-1的表达与模型组相比明显减少（P〈0．05）。结论AD模型大鼠顶叶皮质神经元β-分泌酶及PS-1表达水平明显上调,人参皂甙Rb1可明显改善模型动物上述蛋白的异常表达,对神经元具有明显保护和营养作用。     

干扰素-α和-γ对灌流假孕大鼠卵巢黄体的作用

利用假孕大鼠卵巢体外灌流方法研究干扰素－α和－γ对黄体分泌孕酮和前列腺素Ｆ－２α的作用,并测定灌流后卵巢中３β－羟甾脱氢酶和２０α－羟甾脱氢酶的活性。观察灌流假孕第８天大鼠卵巢结果表明,三种不同剂量（５０、１００、１０００ｕ／ｍｌ）的干扰素－α和－γ均能抑制孕酮的分泌,但干扰素－α的抑制作用仅在短时间内发生,干扰－α和－γ均有抑制ｈＣＧ诱导孕酮分泌的作用,但有剂量和作用时间差异。两种不同类型的干扰素对卵巢分泌前列腺素Ｆ２α无显著作用。干扰－α对灌流８小时后卵巢中３β－羟甾脱氢酶的活性无显著作用,但是干扰素－γ显著抑制３β－羟甾脱氢酶的活性,两种类型的干扰素对２０α－羟甾脱氢酶的活性无显著作用。实验结果提示：两种类型的干扰素都能降低灌流假孕大鼠卵巢黄体孕酮的水平,但是呈现不同的抑制机制。     

IGF-1对缺血性脑损伤大鼠脑内神经发生的影响

目的:建立大鼠单侧局灶脑缺血模型,观察胰岛素样生长因子-1(IGF-1)对局灶脑缺血后的鼠脑神经发生及增殖后细胞生存的影响.方法:用健康雄性SD大鼠建立大脑中动脉阻塞(MCAO)模型,随机分成假手术组,缺血对照组和IGF-1治疗组.各组再按不同的治疗时间分为7d、14d、28d、42d组.免疫组化法观察BrdU、PSA-NCAM的变化,免疫双标法观察BrdU/PSA-NCAM、BrdU/MAP2和BrdU/GFAP的共同表达变化.结果:BrdU标记细胞和PSA-NCAM标记细胞计数均在缺血后第7d最多,分别是缺血对照组的4.0倍和1.8倍,是假手术组的9.9倍和5.4倍.BrdU和PSA-NCAM双标细胞在缺血发生后双侧SVZ和DG区可以检测到,于第7d计数最多,之后逐渐降低;而BrdU和MAP2以及BrdU和GFAP双标细胞却从第14d开始逐渐增多,直到第42d.随着BrdU/PSA-NCAM双标阳性表达的逐渐降低,BrdU/MAP2双标阳性表达逐渐增高,呈现此消彼涨的变化.结论:IGF-1侧脑室注射后,在早期(7d内)诱导了缺血性脑损伤后神经细胞的增殖;在中期(7d-14d)诱导了新生细胞的迁移;在后期(14d后)伴随着迁移的进行新生细胞逐渐发生了分化.     

大鼠局灶性脑缺血后KCl诱导皮层扩散性抑制的体光学成像

采用线栓法制备大鼠大脑中动脉栓塞(middlecerebralarteryocclusion,MCAO)模型,在额叶皮层用KCl诱导产生皮层扩散性抑制(corticalspreadingdepression,CSD)。MCAO4h后,利用550nm内源信号光学成像(opticalintrin-sicsignalimaging,OISI)监测局灶性脑缺血后大鼠顶-枕叶皮层内源光信号变化。成像1h内观测到一系列诱导CSD波(14±3次),CSD波局限于顶-枕叶皮层中央区域扩展,以光强的显著下降为特征;而旁侧区域光强无明显改变,不具备CSD波特征,表明CSD波未传播到该区域。随后TTC染色证明上述旁侧区域已经梗死。实验表明:MCAO后4h,皮层区域旁侧部分会梗死;CSD波的OIS变化可用来区分缺血梗死区和外周供血较为完整区域(未梗死区)。     

Cornel Iridoid Glycoside Inhibits Inflammation and Apoptosis in Brains of Rats with Focal Cerebral Ischemia

The capacity of cornel iridoid glycoside (CIG) to suppress the manifestations of ischemic stroke was investigated. CIG was administered to rats by the intragastric route once daily for 7 days. Focal cerebral ischemia was induced by 2 h of middle cerebral artery occlusion followed by 24 h of reperfusion. In non-treated rats large infarct areas were observed within 24 h of reperfusion. Examination of the ischemic cerebral cortex revealed microglia and astrocyte activation, increased interleukin-1β (IL-1 β) and tumor necrosis factor-α (TNF-α) concentrations, increased DNA fragmentation in the ischemia penumbra, elevated Bax expression, increased caspase-3 cleavage, and decreased Bcl-2 expression. Pretreatment with CIG decreased the infarct area, DNA fragmentation, IL-1β and TNF-α concentrations, microglia and astrocyte activation, Bax expression, and caspase-3 cleavage while increasing Bcl-2 expression. CIG exerts anti-neuroinflammatory and anti-apoptotic effects which should prove beneficial for prevention or treatment of stroke.     

IGF-1对不同年龄缺血性脑损伤大鼠神经发生的影响

目的:检测胰岛素样生长因子-1(IGF-1)对青年和老年大鼠局灶脑缺血后神经发生及其后细胞生存的影响.方法:健康雄性SD青年鼠(3-4个月)和老年鼠(1年)随机分组,侧脑室注入IGF-1,1天后进行大鼠大脑中动脉阻塞(MCAO),对照组由生理盐水取代.采用BrdU标记方法鉴定MCAO后7d和28d的增殖细胞.BrdU于MCAO后第6d由腹腔注入.免疫组化法检测7天后BrdU、PSA-NCAM标记细胞和28天后BrdU、BrdU/MAP2双标细胞.结果:老年组中BrdU阳性细胞的数目7d后较对照组增加5.1倍;青年纽中BrdU阳性细胞的数目7d后较对照组增加5.5倍.28d后,BrdU阳性细胞的残留率在青年IGF-1处理组和老年IGF-1处理组中分别是79.2%和75.1%,分别相对于对照组的77.1%和52.3%.老年组中PSA-NCAM阳性细胞的数目7d后较对照组增加3.2倍;青年组中PSA-NCAM阳性细胞的数目7d后较对照组增加3.7倍.28d后,BrdU/MAP2阳性细胞在青年IGF-1处理组较对照组增加7.0倍,在老年IGF-1处理组较对照组增加4.9倍.结论:此结果提示局部应用IGF-1进行缺血前预处理,在青年鼠和老年鼠中均能诱导神经发生,且在老年鼠中能明显提高神经发生后的增殖细胞的生存率和向神经元分化的能力.这一研究结果将有助于研究IGF-1在中老年脑损伤病人中的治疗性应用.     

Epileptogenesis after Experimental Focal Cerebral Ischemia

Cerebrovascular diseases are one of the most common causes of epilepsy in adults, and the incidence of stroke-induced epileptogenesis is increasing as the population ages. The mechanisms that lead to stroke-induced epileptogenesis in a subpopulation of patients, however, are still poorly understood. Recent advances in inducing epileptogenesis in rodent focal ischemia models have provided tools that can be used to identify the risk factors and neurobiologic changes leading to development of epilepsy after stroke. Here we summarize data from models in which epileptogenesis has been studied after focal ischemia; photothrombosis, middle cerebral artery (MCA) occlusion with filament, and endothelin-1-induced MCA occlusion. Analysis of the data indicates that neurobiologic changes occurring during stroke-induced epileptogenesis share some similarities to those induced by status epilepticus or traumatic brain injury. Special issue dedicated to Dr. Simo S. Oja     

Ephrin-B2促进大鼠局灶脑缺血再灌注后VEGF表达及血管新生

目的:探讨Ephrin-B2对大鼠脑缺血再灌注后脑组织中血管新生的调节作用及其可能的机制。方法:雄性SD大鼠随机分为正常组及、缺血再灌注组及Ephrin-B2干预组,后两组再分为4天、7天、14天、28天亚组;线栓法制备局灶性大脑中动脉缺血再灌注模型;改良神经功能评分(modified neurological severity scores mNSS)评分法对各时间点模型进行评分;Western blot及荧光定量PCR检测缺血脑组织中血管内皮生长因子(Vascular Endothelial Growth Factor VEGF)的表达;以免疫荧光双标法定位VEGF表达的细胞类型;以CD31+BrdU计数缺血半暗带中新生微血管密度(microvessel densityMVD)。结果:Ephrin-B2干预组与缺血再灌注组各时间点亚组比较,新生微血管密度测定计数较缺血再灌注组均显著增加(P0.05),神经功能评分均显著降低(P0.05),VEGF mRNA水平及蛋白表达水平均显著增加(P0.05),VEGF主要表达于CD31阳性的血管内皮细胞。结论:Ephrin-B2通过上调VEGF的表达促进脑缺血再灌注后缺血半暗带血管新生,从而促进神经功能缺失的修复。     

Reperfusion Promotes Mitochondrial Dysfunction following Focal Cerebral Ischemia in Rats

Background and Purpose

Mitochondrial dysfunction has been implicated in the cell death observed after cerebral ischemia, and several mechanisms for this dysfunction have been proposed. Reperfusion after transient cerebral ischemia may cause continued and even more severe damage to the brain. Many lines of evidence have shown that mitochondria suffer severe damage in response to ischemic injury. The purpose of this study was to observe the features of mitochondrial dysfunction in isolated mitochondria during the reperfusion period following focal cerebral ischemia.

Methods

Male Wistar rats were subjected to focal cerebral ischemia. Mitochondria were isolated using Percoll density gradient centrifugation. The isolated mitochondria were fixed for electron microscopic examination; calcium-induced mitochondrial swelling was quantified using spectrophotometry. Cyclophilin D was detected by Western blotting. Fluorescent probes were used to selectively stain mitochondria to measure their membrane potential and to measure reactive oxidative species production using flow cytometric analysis.

Results

Signs of damage were observed in the mitochondrial morphology after exposure to reperfusion. The mitochondrial swelling induced by Ca²⁺ increased gradually with the increasing calcium concentration, and this tendency was exacerbated as the reperfusion time was extended. Cyclophilin D protein expression peaked after 24 hours of reperfusion. The mitochondrial membrane potential was decreased significantly during the reperfusion period, with the greatest decrease observed after 24 hours of reperfusion. The surge in mitochondrial reactive oxidative species occurred after 2 hours of reperfusion and was maintained at a high level during the reperfusion period.

Conclusions

Reperfusion following focal cerebral ischemia induced significant mitochondrial morphological damage and Ca²⁺-induced mitochondrial swelling. The mechanism of this swelling may be mediated by the upregulation of the Cyclophilin D protein, the destruction of the mitochondrial membrane potential and the generation of excessive reactive oxidative species.     

Human-Derived Physiological Heat Shock Protein 27 Complex Protects Brain after Focal Cerebral Ischemia in Mice

Although challenging, neuroprotective therapies for ischemic stroke remain an interesting strategy for countering ischemic injury and suppressing brain tissue damage. Among potential neuroprotective molecules, heat shock protein 27 (HSP27) is a strong cell death suppressor. To assess the neuroprotective effects of HSP27 in a mouse model of transient middle cerebral artery occlusion, we purified a “physiological” HSP27 (hHSP27) from normal human lymphocytes. hHSP27 differed from recombinant HSP27 in that it formed dimeric, tetrameric, and multimeric complexes, was phosphorylated, and contained small amounts of αβ-crystallin and HSP20. Mice received intravenous injections of hHSP27 following focal cerebral ischemia. Infarct volume, neurological deficit scores, physiological parameters, and immunohistochemical analyses were evaluated 24 h after reperfusion. Intravenous injections of hHSP27 1 h after reperfusion significantly reduced infarct size and improved neurological deficits. Injected hHSP27 was localized in neurons on the ischemic side of the brain. hHSP27 suppressed neuronal cell death resulting from cytochrome c-mediated caspase activation, oxidative stress, and inflammatory responses. Recombinant HSP27 (rHSP27), which was artificially expressed and purified from Escherichia coli, and dephosphorylated hHSP27 did not have brain protective effects, suggesting that the phosphorylation of hHSP27 may be important for neuroprotection after ischemic insults. The present study suggests that hHSP27 with posttranslational modifications provided neuroprotection against ischemia/reperfusion injury and that the protection was mediated through the inhibition of apoptosis, oxidative stress, and inflammation. Intravenously injected human HSP27 should be explored for the treatment of acute ischemic strokes.     

大鼠局灶性脑缺血后KCl诱导皮层扩散性抑制的体光学成像

采用线栓法制备大鼠大脑中动脉栓塞(middle cerebral artery occlusion,MCAO)模型,在额叶皮层用KCl诱导产生皮层扩散性抑制(cortical spreadingdepression,CSD).MCA04 h后,利用550 nm内源信号光学成像(optical intrinsic signalimaging,OISI)监测局灶性脑缺血后大鼠顶-枕叶皮层内源光信号变化.成像1 h内观测到一系列诱导CSD波(14±3次),CSD波局限于顶-枕叶皮层中央区域扩展,以光强的显著下降为特征;而旁侧区域光强无明显改变,不具备CSD波特征,表明CSD波未传播到该区域.随后TIC染色证明上述旁侧区域已经梗死.实验表明:MCAO后4h,皮层区域旁侧部分会梗死;CSD波的0IS变化可用来区分缺血梗死区和外周供血较为完整区域(未梗死区).     

光学成像观测大鼠局灶性脑缺血的动态过程

采用 550 nm 内源信号光学成像 (optical intrinsic signal imaging , OISI) 监测左侧大脑中动脉栓塞 (middle cerebral artery occlusion , MCAO) 局灶性脑缺血大鼠顶叶皮层 . MCAO 后 4 h 内,观测到一系列自发扩散性抑制 (spreading depression , SD) 波 (10.3±4.6) 次 . 前 2 h 内的 SD 波通常会侵袭整个左侧顶叶皮层,但光信号有明显的区域差异 . 后 2 h 内的 SD 波局限于顶叶皮层中央区域,且传播面积逐次减少;旁侧区域光强基线逐步升高, 4 h 时,反射光强升高 (8.4±1.2) %. 随后 TTC 染色证明上述旁侧区域已经梗死 . 实验表明光学成像为确定缺血半暗带并监测其动态发展提供了一种有效方法 .