Effect of Nimodipine on Cerebral Edema of Rats with Diffuse Axonal Injury

目的:评价尼莫地平对弥漫性轴索损伤(DAI)大鼠脑水肿的影响.方法:将200只Wistar大鼠随机分为DAI组和治疗组,建立DAI模型后治疗组给予尼奠地平注射液腹腔注射,剂量为0.5 mg/(kg·d),分别于伤前和伤后6h、1d、3d、7d通过检测脑组织含水量反映脑水肿情况,通过观察伊文蓝(EB)含量反映血脑屏障通透性变化.结果:DAI后脑组织含水量和脑组织EB含量峰值分别出现在伤后1d和3d,2组内不同时间点脑组织水含量和脑EB含量差异有统计学意义(均P＜0.001),伤后6h和1d、3d时尼莫地平治疗组脑组织水含量明显低于DAI组(P＜0.05或P＜0.01),伤后6h和1d、3d、7d尼莫地平治疗组脑EB含量明显低于DAI组(均P＜0.01).结论:尼莫地平可以有效控制DAI大鼠的血脑屏障通透性,减轻脑水肿.     

大鼠创伤性脑损伤后Claudin-5表达水平变化的研究

目的：探讨大鼠创伤性脑损伤后不同时间点血脑屏障通透性及Claudin-5表达水平的变化,为进一步研究创伤后脑水肿的机制及治疗时机提供理论依据。方法：大鼠随机分为对照组和脑损伤组,参照Feeney＇s的自由落体致伤法,制作大鼠顶叶局灶皮质挫裂伤模型。应用伊文兰（evansblue）法测定伤后不同时间点损伤灶皮层脑组织中EB含量;应用Westernblot法检测损伤灶脑微血管内皮细胞紧密连接相关蛋白Claudin-5的表达水平。结果：损伤灶皮层中EB含量在伤后1～6h明显增多,高峰期在3h。Westernblot结果显示损伤后1～6h,Claudin-5表达水平较对照组显著降低（P〈0.05）,3h最明显,24h与对照组差异无统计学意义。结论：大鼠顶叶局部脑挫裂伤可能通过下调紧密连接相关蛋白Claudin-5的表达水平,开放紧密连接,增加血脑屏障的通透性。     

尼莫地平对弥漫性轴索损伤大鼠脑水肿的影响

【摘要】 目的：评价尼莫地平对弥漫性轴索损伤（DAI）大鼠脑水肿的影响。 方法：将100只Wistar大鼠随机分为DAI组和治疗组,治疗组于造模后给予尼莫地平注射液腹腔注射,剂量为0.5mg/kg体重/d,分别于伤前和伤后6h、1d、3d、7d通过检测脑组织含水量反应脑水肿情况,通过观察伊文蓝（EB）含量反应BBB通透性变化。结果：DAI后脑组织含水量和脑组织EB含量呈先升高后下降的趋势,峰值分别出现在伤后1d和3d,DAI组和尼莫地平治疗组不同时间的变化趋势比较差异有统计学意义（P<0.05),2组峰值比较差异有统计学意义（P<0.05),尼莫地平治疗组较低。结论：使用尼莫地平可以有效控制弥漫性轴索损伤大鼠的血脑屏障通透性,减轻脑水肿。     

灯盏花素对大鼠脑创伤的保护作用

目的:观察灯盏花素对大鼠脑创伤后脑水肿、血脑屏障通透性和氧自由基的影响。方法:84只大鼠随机分为假手术组,模型组及低(25 mg/kg×2)、高(50 mg/kg×2)剂量灯盏花素组。采用液压颅脑损伤模型,脑创伤的同时尾静脉注射灯盏花素,8 h后重复给药一次。检测各组大鼠脑创伤后24 h脑组织含水量,伊文思蓝、超氧化物歧化酶(SOD)和丙二醛(MDA)的含量。结果:模型组大鼠脑创伤后脑组织含水量,伊文思蓝、MDA和SOD含量与假手术组有显著性差别。大鼠脑创伤后注射低剂量和高剂量灯盏花素均可显著降低脑组织含水量、伊文思蓝含量和MDA含量,显著增加SOD含量(P＜0．05)。结论:灯盏花素可减轻大鼠脑创伤后脑水肿,其对大鼠脑创伤的保护作用与降低血脑屏障通透性、抑制氧自由基反应有关。     

肿瘤侵袭、浸润和转移对血脑屏障通透性的影响

血脑屏障是一个可扩散屏障,位于血液与中枢神经系统(CNS)神经组织之间,只允许水和小分子的脂溶性物质凭借浓度梯度自由扩散,是由脑毛细血管内皮细胞(BMECs)及细胞间紧密连接、基底膜、周细胞、星形胶质细胞脚板和极狭小的细胞外隙共同组成的一个细胞复合体。正常血脑屏障具有高度选择性,能防止毒素及其他有害物质进入脑实质内,对维持CNS内环境的稳态起着重要的作用。该结构损伤必将导致脑内微环境变化,从而引起脑神经细胞功能、代谢与结构的改变。Brightmann等提出血管内皮细胞之间的紧密连接是形成血脑屏障的关键因素,与其他器官毛细血管内皮细胞不同的是:BMECs膜上无窗孔,细胞间有紧密连接,缺少收缩性蛋白,吞饮小泡很少,细胞内含有丰富的酶系统,并且内皮细胞膜表面有负电荷,生理情况下只允许气体分子及分子量小于400～600Da的脂溶性小分子通过。     

尼莫地平对弥散性轴索损伤大鼠血脑屏障通透性的影响研究

目的:研究尼莫地平对弥散性轴索损伤(DAI)大鼠血脑屏障(BBB)通透性的影响。方法:取大鼠随机分为DAI组和尼莫地平组,每组40只,2组大鼠建立DAI后,尼莫地平组腹腔注射给药0.5mg·kg-1·d-1,分别于建模前和建模后0.25、1、3、7d检测脑组织含水量和伊文蓝(EB)含量以考察脑水肿情况和BBB通透性变化。结果:DAI后,2组大鼠脑组织含水量和EB含量均呈先升高后降低的趋势,峰值分别出现在建模后1d和3d;与DAI组比较,尼莫地平组脑组织含水量和EB含量的峰值均明显降低(P<0.05)。结论:尼莫地平可以有效减轻DAI后脑水肿情况,降低BBB的通透性。     

中性粒细胞弹性蛋白酶在实验性脑出血大鼠脑组织中的动态变化

目的通过测定中性粒细胞弹性蛋白酶（NE）在实验性脑出血大鼠脑组织中的动态变化从而来探讨NE的含量和脑出血关系。方法将雄性Wistar大鼠随机分为对照组和ICH模型组,分别于束后6h,12h,24h,48h和72h取脑,测定脑组织NE的含量及脑含水量。结果ICH大鼠脑组织NE含量明显增加。6h即升高,24h达最高峰（P〈0．01）。以后逐渐下降,72h与对照组差异仍然具有统计学意义;ICH大鼠脑组织含水量升高较慢。48h达高峰（P〈0．01）。结论实验性脑出血大鼠脑组织内NE含量的升高与大鼠脑出血后脑组织水肿密切相关,NE增加可能是脑出血后早期引起血脑屏障开放、血管源性脑水肿形成的重要原因之一。     

纳米氧化铝对小鼠血脑屏障通透性的影响

目的探讨纳米氧化铝颗粒对小鼠血脑屏障通透性的影响。方法 3月龄ICR小鼠用滴鼻法染毒,为了比较纳米铝作用的颗粒毒性和化学毒性,将小鼠分为对照组、微米铝组、纳米碳组、纳米铝组和铝离子组;为了比较纳米铝作用的剂量-效应关系,将小鼠分为对照组、低剂量组、中剂量组和高剂量组。每只小鼠每次染毒10μl,3次/d,实验时间为30 d。染毒结束后,用硝酸镧染色法检测血脑屏障通透性;用免疫荧光法检测紧密连接蛋白ZO-1、Occludin蛋白表达;用western blot法检测ZO-1,Claudin-5蛋白表达。结果硝酸镧染色结果表明,对照组的硝酸镧颗粒聚集在毛细血管中央,未见对血管内皮的穿透;微米铝组和纳米碳组有部分高电子密度的硝酸镧颗粒位于毛细血管内壁中央,显示血脑屏障的通透性增高;纳米铝和铝离子组有大量硝酸镧颗粒位于血管内壁中央,形成致密的黑色条带,显示血脑屏障受损和通透性增高。免疫荧光法检测紧密连接蛋白ZO-1、Occludin蛋白表达和western blot法检测ZO-1,Claudin-5蛋白表达结果表明,紧密连接蛋白ZO-1、Occludin和Claudin-5蛋白表达在对照组均为高表达,微米铝和纳米碳组表达下调(P<0.0001),纳米铝和铝离子组的表达量最低(P<0.0001)。且这种紧密连接蛋白表达的降低与纳米铝的染毒剂量间有剂量-反应关系(P<0.0001)。结论纳米氧化铝可以降低血脑屏障通透性,这种作用表现为纳米的颗粒作用和铝化学毒性作用的相加。其发生机制与紧密连接蛋白ZO-1、Occludin和Claudin-5蛋白表达降低有关。     

大鼠急性颅脑损伤后 IL-8在颅内表达的动态观察

目的：探讨大鼠急性颅脑外伤后颅内 IL-8的表达在继发性脑损伤中的作用及意义。方法将健康成年 SD 大鼠70只,随机分为对照组和损伤组后12、24、72、120 h,1周、2周组,每组10只。采用液压打击致伤法制作大鼠急性颅脑损伤模型。观察 IL-8在损伤灶周围的表达,并作脑组织含水量测量。结果损伤后12 h 时即可见坏组织死周围和皮层散在表达 IL-8的棕黄色阳性细胞,24 h 时阳性细胞明显增多达到高峰,不仅在神经元表达,也在胶质细胞、部分血管内皮细胞以及聚集成堆的中性粒细胞内表达;伤后72 h 阳性细胞开始减少,但经过光密度值检测仍高于对照组（P ＜0．05）。损伤后7 d 阳性细胞略有所回升,至损伤后14 d 阳性细胞明显减少,基本趋于平稳。损伤后病变侧各时间点阳性细胞数与对照组比较,差异均有统计学意义（P ＜0．05）。假手术组大鼠各时间点脑组织含水量差异均无统计学意义（P ＞0．05）。损伤组各时间点（除伤后14 d）脑含水量与假手术组相比均有增高（P ＜0．05）,在伤后24 h 达高峰,持续到72 h,伤后14 d 时脑含水量较对照组虽有所升高,但差异无统计学意义（P ＞0．05）。结论IL-8的表达与脑损伤后脑组织的病理生理学改变密切相关,在损伤早期 IL-8的高表达参与了脑水肿形成等继发性神经元损害过程,后期 IL-8的稍高表达可能与神经元修复有关。     

安宫牛黄丸对脑外伤后血脑屏障损伤及脑水肿作用机制的研究

目的系统地分析安宫牛黄丸对脑外伤后血脑屏障损伤及脑水肿的影响，阐明其作用的分子机制，揭示其开窍醒脑的机理，为临床合理应用及进一步开发利用其治疗脑外伤后所致脑水肿提供依据。方法以Feeney法建立大鼠闭合性脑损伤模型，同绕脑外伤性脑水肿中血脑屏障损伤的主要环节，探讨安宫牛黄丸对脑损伤后脑含水量、BBB通透性以及神经细胞突触数量的影响，系统地分析安宫牛黄丸对血脑屏障损伤及脑水肿的影响，阐明其作用的分子机制，揭示其开窍醒脑的机理。结果与假手术组比较，模型组损伤侧脑含水量及脑皮质EB含量明显增加（P〈0．01）。与模型组比较，安宫牛黄丸组损伤侧脑含水量及脑皮质EB含量明显降低（P〈0．05）。与假手术组比较，模型组损伤侧脑皮质电镜下突触密度显著性降低（P〈0．01），与模型组比较，安宫牛黄丸组损伤侧脑皮质电镜下突触密度明显增加（P〈0．05）。结论安宫牛黄丸可减轻脑水肿、保护血脑屏障、降低毛细血管通透性、提高脑组织对缺血、缺氧的耐受性，从而保护脑组织。     

Traumatic brain injury opens blood–brain barrier to stealth liposomes via an enhanced permeability and retention (EPR)-like effect

The opening of the tight junctions in the blood–brain barrier (BBB) following traumatic brain injury (TBI) is hypothesized to be sufficient to enable accumulation of large drug carriers, such as stealth liposomes, in a similar manner to the extravasation seen in tumor tissue via the enhanced permeability and retention (EPR) effect. The controlled cortical impact model of TBI was used to evaluate liposome accumulation in mice. Dual-radiolabeled PEGylated liposomes were administered either immediately after induction of TBI or at increasing times post-TBI to mimic the likely clinical scenario. The accumulation of radiolabel in the brain tissue ipsilateral and contralateral to the site of trauma, as well as in other organs, was evaluated. Selective influx of liposomes occurred at 0–8?h after injury, while the barrier closed between 8 and 24?hr after injury, consistent with reports on albumin infiltration. Significantly enhanced accumulation of liposomes occurred in mice subjected to TBI compared to anaesthetized controls, and accumulation was greater in the injured versus the contralateral side of the brain. Thus, stealth liposomes show potential to enhance drug delivery to the site of brain injury with a wide range of encapsulated therapeutic candidates.     

大鼠脑损伤后星形胶质细胞结构和NO、ET的变化

目的观察脑损伤后星形胶质细胞(Astrocyte,Ast)形态学变化及脑组织一氧化氮(n itric oxide,NO)、内皮素(endothlin,ET)含量变化。方法利用M arm arou创立的模型造成大鼠脑损伤,于伤后6h、24h、48h、120h胶质纤维酸性蛋白(glial fibrillary ac id ic prote in,GFAP)免疫组化染色观察Ast形态学变化并测脑组织NO、ET含量。结果脑损伤后6h出现GFAP表达的升高,48h达高峰,120h有回落但仍处于较高水平。脑组织NO和ET含量脑损伤后代偿性增加,24h-48h维持在较高水平,与对照组差异有统计学意义(P<0.01)。结论Ast、NO和ET在颅脑损伤的病理过程中有重要作用,且三者在损伤过程中存在一定变化规律。     

大鼠颅脑损伤急性期水通道蛋白4表达变化的研究

目的探讨水通道蛋白4(AQP4)在大鼠重型颅脑损伤时的表达变化及其与脑水肿间的关系。方法98只成年雄性Wistar大鼠,随机分为对照组及实验组(伤后0.5、2、6、12、24、48、72 h共7组,对照组不打击)。制作大鼠液压冲击颅脑损伤模型,分别于伤后0.5、2、6、12、24、48、72 h采用干湿比重法测脑组织含水量,半定量反转录聚合酶链反应(RT-PCR)检测脑组织AQP4 mRNA表达及其变化。结果脑组织AQP4 mRNA在伤后0.5 h开始表达上调,2、6、12 h依次增高,24 h达到峰值(P<0.05),72 h时仍维持较高水平。脑组织含水量与AQP4 mRNA表达变化一致。经相关性分析,AQP4 mRNA的表达与脑组织含水量呈正相关(r=0.095,P<0.05)。结论重型脑损伤急性期,AQP4 mRNA表达变化与颅脑损伤后脑水肿的形成和发展密切相关。AQP4可能参与重型脑损伤后脑水肿的形成并起重要作用。     

创伤性脑损伤患者血清中sFas、FasL、NSE的变化与临床观察

目的　观察创伤性脑损伤患者不同伤情、不同时期血清中可溶性 Fas(Soluble Fas,s Fas)、Fas配体(Fas ligand,Fas L)、神经元特异性烯醇化酶 (neuron- specific enolase,NSE)的动态变化及其内在联系 ,借此间接了解创伤性脑损伤后神经细胞损伤的规律 ,为探索新的神经保护性治疗措施提供理论依据。方法　选择 35例单纯创伤性颅脑损伤患者 ,依据入院时 GCS(Glasgow coma score)评分将其分为轻型组、中型组和重型组。入选患者分别于伤后2 4 h、72 h、7d、1 4 d抽取外周静脉血 ,运用双抗体夹心酶联免疫分析法 (EL ISA)测定血清中 Fas L、s Fas、NSE含量。结果　 (1 )伤后 2 4 h Fas L、s Fas均升高 ,并于伤后 72 h左右达到高峰 ,后逐渐下降 ,至 2周左右接近正常。 (2 ) NSE于伤后 2 4 h即开始升高 ,且损伤越重升高越显著。 (3) s Fas、Fas L与 NSE呈正相关。结论　 (1 )创伤性脑损伤后神经细胞的损伤存在原发和继发两种机制。 (2 ) Fas/ Fas L系统在继发性脑损伤中起重要作用 ,s Fas的表达增强在一定程度上对神经组织起到保护作用。 (3)创伤性脑损伤后测定血清中 Fas L、s Fas可间接了解继发性脑损伤的程度 ,借此可以为临床探索新的神经保护措施提供理论依据     

Synthetic gelatinases inhibitor attenuates electromagnetic pulse-induced blood-brain barrier disruption by inhibiting gelatinases-mediated ZO-1 degradation in rats

Previously we found that exposure to electromagnetic pulse (EMP) induced an increase in blood-brain-barrier (BBB) permeability and the degradation of tight junction protein ZO-1 in rats. Matrix metalloproteinases (MMPs), in particular gelatinases (MMP-2 and MMP-9), play a key role in degradation of tight junction proteins, are known mediators of BBB compromise. We hypothesized that the degradation of ZO-1 by gelatinases contributed to EMP-induced BBB opening. To test this hypothesis, the mRNA level of ZO-1, protein levels of MMP-2, MMP-9 and tissue inhibitor of metalloproteinases (TIMP-1 and TIMP-2) were detected in rat cerebral cortex after exposing rats to EMP at 200 kV/m for 200 pulses. It was found that the mRNA level of ZO-1 was unaltered at different time points after EMP exposure. The protein levels of MMP-2 and MMP-9 significantly increased at 3 h and 0.5 h, respectively. However, TIMP-1 (inhibitor of MMP-9) and TIMP-2 (inhibitor of MMP-2) only moderately increased after EMP exposure. In addition, in situ zymography results showed that the gelatinase activity increased in cerebral microvessels at 3 h after EMP exposure. When rats were treated with gelatinases inhibitor (SB-3CT) before EMP exposure, the EMP-induced BBB opening was attenuated and the ZO-1 degradation was reversed. Our results suggested that EMP-induced BBB opening was related to gelatinase mediated ZO-1 degradation.     

Effects of alcohol consumption on traumatic brain injury

It has been well known that alcohol consumption affects traumatic brain injury. The mechanism of detrimental effect of ethanol on traumatic brain injury has not been clarified. This review focused on the relationship among traumatic brain injury, ethanol and aquaporin-4. We have reported that ethanol increased brain edema after brain contusion and decreased survival rates in rats. It was suggested that increasing brain edema by ethanol after brain contusion may be caused by oxidative stress. Brain edema consists of cytotoxic brain edema, vasogenic brain edema, interstitial brain edema and osmotic edema. Ethanol mainly increases cytotoxic brain edema. Both alcohol consumption and brain contusion cause oxidative stress. Antioxidant treatment decreases cytotoxic brain edema. Aquaporin-4, an water channel, was increased by ethanol 24 hr after traumatic brain injury in rat. The aquaporin-4 inhibitor decreased brain edema after brain contusion and increased survival rates under ethanol consumption. Aquaporin-4 may have strict relation between ethanol and brain edema increasing after brain contusion.     

EMP-induced alterations of tight junction protein expression and disruption of the blood–brain barrier

The blood–brain barrier (BBB) is critical to maintain cerebral homeostasis. In this study, we examined the effects of exposure to electromagnetic pulse (EMP) on the functional integrity of BBB and, on the localization and expression of tight junction (TJ) proteins (occludin and ZO-1) in rats. Animals were sham or whole-body exposed to EMP at 200 kV/m for 400 pulses. The permeability of BBB in rat cerebral cortex was examined by using Evans Blue (EB) and lanthanum nitrate as vascular tracers. The localization and expression of TJ proteins were assessed by western blot and immunofluorescence analysis, respectively. The data indicated that EMP exposure caused: (i) increased permeability of BBB, and (ii) altered localization as well as decreased levels of TJ protein ZO-1. These results suggested that the alteration of ZO-1 may play an important role in the disruption of tight junctions, which may lead to dysfunction of BBB after EMP exposure.     

Ginsenoside Rg1 ameliorates blood–brain barrier disruption and traumatic brain injury via attenuating macrophages derived exosomes miR-21 release

During the traumatic brain injury (TBI), improved expression of circulatory miR-21 serves as a diagnostic feature. Low levels of exosome-miR-21 in the brain can effectively improve neuroinflammation and blood–brain barrier (BBB) permeability, reduce nerve apoptosis, restore neural function and ameliorate TBI. We evaluated the role of macrophage derived exosomes-miR-21 (M-Exos-miR-21) in disrupting BBB, deteriorating TBI, and Rg1 interventions. IL-1β-induced macrophages (IIM)-Exos-miR-21 can activate NF-κB signaling pathway and induce the expressions of MMP-1, -3 and -9 and downregulate the levels of tight junction proteins (TJPs) deteriorating the BBB. Rg1 reduced miR-21-5p content in IIM-Exos (RIIM-Exos). The interaction of NMIIA–HSP90 controlled the release of Exos-miR-21, this interaction was restricted by Rg1. Rg1 could inhibit the Exos-miR-21 release in peripheral blood flow to brain, enhancing TIMP3 protein expression, MMPs proteolysis, and restricting TJPs degradation thus protected the BBB integrity. Conclusively, Rg1 can improve the cerebrovascular endothelial injury and hold the therapeutic potential against TBI disease.     

Human serum albumin nanoparticles modified with apolipoprotein A-I cross the blood-brain barrier and enter the rodent brain

Nanoparticles made of human serum albumin (HSA) and modified with apolipoproteins have previously been shown to transport drugs, which normally do not enter the brain, across the blood-brain barrier (BBB). However the precise mechanism by which nanoparticles with different apolipoproteins on their surface can target to the brain, as yet, has not been totally elucidated. In the present study, HSA nanoparticles with covalently bound apolipoprotein A-I (Apo A-I) as a targetor for brain capillary endothelial cells were injected intravenously into SV 129 mice and Wistar rats. The rodents were sacrificed after 15 or 30?min, and their brains were examined by transmission electron microscopy. Apo A-I nanoparticles could be found inside the endothelial cells of brain capillaries as well as within parenchymal brain tissue of both, mice and rats, whereas control particles without Apo A-I on their surface did not cross the BBB during our experiments. The maintenance of tight junction integrity and barrier function during treatment with nanoparticles was demonstrated by perfusion with a fixative containing lanthanum nitrate as an electron dense marker for the permeability of tight junctions.