红细胞对创伤性脑内出血大鼠脑含水量及HO-1表达的影响

目的研究大鼠创伤性脑内出血(TICH)中红细胞对脑含水量和血红素氧合酶-1(HO-1)表达的影响,并分析二者的关系,以探讨红细胞在TICH后脑水肿形成中的作用机制。方法120只大鼠随机分为创伤性脑损伤组(TBI组),TBI加注全血组(WB组),TBI加注溶解红细胞组(LRBC组)和TBI加注压积红细胞组(PRBC组),每组30只。4组均采用自由落体打击法造成大鼠脑外伤。后3组借助立体定向仪分别向伤区脑皮质内注射全血、溶解红细胞或压积红细胞,造成TICH模型。每组于伤后1、3、5d分别处死10只大鼠,5只测伤区脑组织含水量,5只用免疫组化法检测HO-1的表达。结果4组组内比较:TBI、WB和PRBC3组第3d的脑含水量最高(分别为82.85%±0.60%,85.00%±1.12%,84.93%±1.21%),LRBC组第1d的含水量最高(84.44%±0.85%;4组间比较,1d时LRBC组含水量最高,3d时WB和PRBC组含水量最高。在WB、PRBC和LRBC组,HO-1阳性表达的强弱与脑含水量的高低变化相一致。结论红细胞在TICH后迟发性脑水肿的形成中有重要作用,其机制涉及红细胞的降解产物。     

红细胞在实验性脑出血后脑水肿形成中的作用

目的研究红细胞在脑出血后脑水肿形成中的作用。方法向大鼠尾状核分别注入浓缩红细胞（PRBC）、溶解红细胞（LRBC）及不同浓度的大鼠血红蛋白（Hb），并比较鼠脑不同部位脑水肿形成的特点。结果红细胞对脑水肿的影响要在脑出血后第3d，其水肿的严重程度与Hb的浓度呈正相关。结论红细胞对脑出血后脑水肿形成的影响主要在脑出血后第3d，可能与红细胞溶解释放血红蛋白有关。     

银杏达莫对创伤性脑出血大鼠的神经保护机制研究

目的探究银杏达莫对创伤性脑出血(TICH)大鼠的神经保护机制。方法 SD大鼠被随机分为3组(n=10),即对照组、TICH组和银杏达莫组。TICH组和银杏达莫组大鼠通过击打的方法建立TICH模型。银杏达莫组注射银杏达莫,0.4 mL·kg~(-1)x3 d。通过磁共振(MRI)检测脑出血情况;分别通过改良神经功能缺损程度评分(mNSS)和干湿测重法评估神经缺损情况和脑组织含水量;使用TUNEL染色检测脑组织中神经元凋亡情况;Western blot检测蛋白水平。结果 MRI可以清晰的看出建模后TICH组和银杏达莫组脑组织的出血情况。干预后,TICH组大鼠的m NSS评分显著高于对照组(P0.05),银杏达莫组的m NSS评分显著低于TICH组。TICH组大鼠的脑组织含水量显著高于对照组(P0.05),银杏达莫组的脑组织含水量显著低于TICH组(P0.05)。TICH组大鼠的脑组织神经元凋亡率高于对照组(P0.05),银杏达莫组的脑组织神经元凋亡率显著低于TICH组。TICH组大鼠的脑组织中TLR4和MyD88蛋白显著高于对照组(P0.05),银杏达莫组的脑组织中TLR4和MyD88蛋白显著低于TICH组(P0.05)。结论银杏达莫可能通过抑制TLR4/MyD88通路中蛋白的表达抑制炎性反应,并减少脑水肿和神经元的凋亡,从而对TICH大鼠的神经功能发挥保护作用。     

高温对重型颅脑损伤后乳酸、Na+-K+-ATP酶和脑水肿的影响

目的 探讨大鼠重型颅脑损伤后高温对伤灶区脑组织乳酸、Na+-K+-ATP酶和脑水肿的影响.方法 90只SD大鼠随机分为假手术组、颅脑损伤组、伤后高温组,每组又按处死时间点(伤后4 h、1 d、3 d、5 d和7 d)分为五个亚组,每亚组6只.取伤灶区脑组织测含水量、乳酸含量和Na+-K+-ATP酶活性并行电镜检查.结果 高温组脑组织含水量和乳酸含量在伤后各时间点均显著高于颅脑损伤组和假手术组(P＜0.05),而Na+-K+-ATP酶含量显著低于颅脑损伤组和假手术组(P＜0.05),电镜检查发现高温组神经细胞肿胀、血脑屏障破坏程度较颅脑损伤组明显加重.结论 颅脑损伤后高温增加脑组织乳酸生成,同时Na+-K+-ATP酶活性下降,脑水肿加重,故在颅脑损伤后应保持体温在正常范围内,避免体温升高.     

促红细胞生成素对急性脑损伤的保护作用

目的观察重组人促红细胞生成素(r-Epo)对大鼠急性脑损伤后脑细胞凋亡及脑水肿的影响。方法30只大鼠分为A、B、C 3组,B、C 2组用自由落体打击器制作脑外伤模型,C组r-Epo预处理,48 h后断头取脑。制作石蜡切片,TUNEL法检测细胞凋亡,同时用干湿重法测定各组大鼠脑组织含水量。结果与B组比较,C组外伤侧脑组织含水量明显降低(P<0.01),细胞凋亡数明显减少(P<0.01)。结论r-Epo能显著降低急性脑损伤后脑水肿,减少水肿区神经细胞凋亡,对急性损伤后脑组织有良好的保护作用。     

精氨酸加压素对大鼠脑水肿形成及水孔蛋白-4表达的影响

目的 探讨精氨酸加压素(AVP)对大鼠脑水肿形成和水孔蛋白-4(AQP4)表达的影响.方法 90只SD大鼠随机分为正常对照组、假手术6 h、1 d、3 d、5 d组及AVP6 h、1 d、3 d、5 d组.于大鼠侧脑室注射AVP后,分别于相应时间点对脑室周围组织进行脑含水量测定,免疫组化技术检测脑室周围组织AQP4的表达.结果 假手术组与正常对照组脑组织含水量及AQP4表达未见增加.AVP组大鼠侧脑室注射AVP 6 h脑室周围脑组织含水量开始增加,1 d即达高峰,与正常对照组比较差异有统计学意义(均P＜0.01),5 d降到基础水平;脑室周围AQP4表达亦在注射AVP 6 h开始增加,1 d即达高峰,与正常对照组比较差异有统计学意义(均P＜0.01),第5 d恢复到基础水平,与脑水肿的变化相一致.结论 AVP可上调AQP4表达,引起大鼠脑含水量增加,导致脑水肿的发生.     

ICAM-1在大鼠弥漫性脑损伤后的脑组织水肿中的表达及其意义

目的探讨ICAM-1在大鼠弥漫性脑损伤后脑水肿中的作用。方法采用Marmarou等人的方法建立大鼠弥漫性脑损伤模型,S-P免疫组化法测定ICAM-1蛋白在外伤后不同时间脑组织中的表达,干湿重法测脑组织含水量,组织切片HE染色观测炎性细胞浸润情况。结果伤后6h,脑组织中ICAM-1蛋白表达明显升高,72h达到高峰,其后下降,7d时仍明显高于假手术对照组(P<0.05)。伤后6h、12h、24h、48h、72h和7d时,脑组织含水量亦明显高于假手术组(P<0.05),同时伤后脑组织中炎性细胞大量聚集。结论大鼠脑外伤诱导了ICAM-1蛋白的表达,ICAM-1通过介导炎性细胞的浸润可能参与了伤后脑水肿的形成过程。     

局灶低温及全脑低温对大鼠创伤性脑损伤后IL-1β与TNF-α的影响研究

目的研究局灶低温及全脑低温治疗对SD大鼠创伤性脑损伤后脑水含量、Na 含量及IL-1β、TNF-α的影响,以探讨局灶低温对创伤性脑损伤的治疗作用及可能机制。方法采用自由落体打击装置造成大鼠创伤性脑损伤,分别于伤后30min开始进行全脑降温、25℃水脑局灶降温治疗,治疗结束后在相应时相点断头处死,采用相关的方法测定伤灶脑组织含量,Na 含量、白细胞介素-1β(IL-1β)和肿瘤坏死因子(TNF-α)活性含量和IL-1β和TNF-αmRNA表达等。结果在含水量方面、在离子含量方面、在IL-1β和TNF-α含量方面以及在IL-1β和TNF-αmRNA表达方面,局灶低温(25℃)组与全脑低温组以及脑外伤模型组相比均呈现不同程度的变化。结论局灶低温(25℃)治疗能明显减轻脑水肿;全脑低温治疗加重脑水肿;其机制之一可能是通过抑制或促进炎性因子IL-1β、TNF-α表达而起作用。     

缺氧预处理对颅脑损伤大鼠脑组织MMP-9表达及含水量的影响

目的观察缺氧预处理对颅脑损伤(TBI)大鼠脑组织基质金属蛋白酶-9(MMP-9)的表达和含水量变化。方法 SD雄性大鼠108只,随机分为对照组(n=6)、缺氧预处理组(HPC组,n=6)、TBI组(n=48)、缺氧预处理+外损组(HPCT组,n=48)。采用干湿重法测定脑组织含水量,RT-q PCR、Western blotting分别测定MMP-9 m RNA及蛋白表达水平。结果 TBI组和HPCT组MMP-9 m RNA在伤后3h、6h、12h、1d、3d明显升高(P0.05),MMP-9蛋白表达和脑组织含水量均在伤后3h、6h、12h、1d、3d、7d明显增加(P0.05)。HPCT组中MMP-9 m RNA在伤后3h、6h、12 h、1d、3d,MMP-9蛋白和脑组织含水量在伤后6h、12h、1d、3d、7 d明显低于TBI组(P0.05)。结论缺氧预处理能抑制颅脑损伤脑组织MMP-9表达从而减轻脑水肿,可能是缺氧预处理对颅脑损伤大鼠发挥脑保护作用的机制之一。     

自发性脑出血中红细胞对血脑屏障通透性的影响

目的研究自发性脑出血(SICH)中红细胞对血脑屏障(BBB)通透性的影响。方法大鼠自体血脑内注射法造成自发性脑出血模型,用脑立体定位仪向大鼠右侧尾状核注入自体全血(WB)或红细胞(RBC)以建立SICH动物模型。分组按照不同时间点(6h、1d、3d、5d)处死大鼠,处死前经尾静脉注射2%伊文思蓝(Evans blue,EB)溶液2mL/kg,取标本后用甲酰胺浸泡法检测脑组织EB含量。结果 BBB通透性检测脑组织EB含量:RBC、WB、SO组6h、1d、3d、5d比较,其中在RBC第1、3天组明显高于6h和5d组,SICH后6h开始升高,1d达到高峰,3d开始恢复,5d有所下降(P0.05)。结论SICH后导致BBB功能障碍,红细胞对BBB结构破坏起至关重要的作用。     

盐酸纳美芬对大鼠颅脑损伤后脑水肿的影响

目的探讨盐酸纳美芬对大鼠颅脑损伤后脑水肿的影响。方法将54只Wistar大鼠按随机数字表法随机分为假手术组、颅脑损伤组及纳美芬治疗组。采用自由落体法建立大鼠颅脑损伤模型,分别于伤后6 h、1 d、3 d、7 d,采用干湿重法检测脑组织含水量,应用免疫组织化学法检测损伤脑组织中水通道蛋白4（AQP4）的表达。结果与假手术组比较,颅脑损伤组和纳美芬治疗组的脑组织含水量及AQP4水平明显升高（P〈0.05）;与颅脑损伤组相比,纳美芬治疗组脑组织含水量及AQP4表达水平明显降低（P〈0.05）。通过相关性分析发现,大鼠颅脑损伤后脑组织AQP4表达水平与脑含水量呈明显正相关性（r=0.676,P〈0.01）。结论盐酸纳美芬可能通过抑制AQP4表达,减轻脑水肿,发挥神经保护作用。     

Sulforaphane enhances aquaporin-4 expression and decreases cerebral edema following traumatic brain injury

Brain edema, the infiltration and accumulation of excess fluid causing an increase in brain tissue volume, often leads to a rise in intracranial pressure and is a key contributor to the morbidity and mortality associated with traumatic brain injury (TBI). The cellular and molecular mechanisms contributing to the development/resolution of TBI-associated brain edema are poorly understood. Aquaporin-4 (AQP4) water channel is expressed at high levels in brain astrocytes, and the bidirectional transport of water through these channels is critical for the maintenance of brain water homeostasis. By using a rodent injury model, we show that TBI decreased AQP4 level in the injury core and modestly increased it in the penumbra region surrounding the core. Postinjury administration of sulforaphane (SUL), an isothiocyanate present in abundance in cruciferous vegetables such as broccoli, attenuated AQP4 loss in the injury core and further increased AQP4 levels in the penumbra region compared with injured animals receiving vehicle. These increases in AQP4 levels were accompanied by a significant reduction in brain edema (assessed by percentage water content) at 3 days postinjury. These findings suggest that the reduction of brain edema in response to SUL administration could be due, in part, to water clearance by AQP4 from the injured brain.     

人工脑脊液冲洗治疗对实验性大鼠脑外伤后低氧诱导因子表达的影响

目的探讨人工脑脊液局灶冲洗治疗对实验性大鼠创伤性脑损伤后脑水肿及低氧诱导因子-1α(HIF-1α)表达的影响。方法采用自由落体打击装置制备大鼠创伤性脑损伤模型,分正常对照组、外伤对照组、生理盐水冲洗治疗组及人工脑脊液冲洗治疗组。于伤后30min开始分别以37℃的生理盐水和人工脑脊液进行局灶冲洗治疗维持3h。伤后4h、1、3、5、7d处死留取脑组织标本,采用干湿重法测伤灶脑组织含水量,RT-PCR方法检测HIF-1αmRNA的表达。结果与外伤对照组相比,生理盐水和人工脑脊液治疗组伤灶脑组织水含量明显降低(P<0.05);脑外伤后4h伤灶脑组织中HIF-1αmRNA表达即明显上升,1d达到高峰,持续至3d,5d开始下降,7d降至正常水平;局灶冲洗治疗后,伤后4h、1d、3d和5d各组脑组织HIF-1αmRNA表达均低于外伤对照组相应各时间点(P<0.05);其中以局灶人工脑脊液冲洗治疗效果最佳。结论局灶人工脑脊液冲洗治疗能明显减轻大鼠伤灶脑水肿,有良好的治疗作用;调节HIF-1α的表达是其脑保护作用的机制之一。     

Glycerol accumulation in edema formation following diffuse traumatic brain injury

Traumatic brain injury (TBI) induces brain edema via water and glycerol transport channels, called aquaporins (AQPs). The passage of glycerol across brain cellular compartments has been shown during edema. Using a modified impact/head acceleration rodent model of diffuse TBI, we assessed the role of hypoxia inducible factor (HIF)-1alpha in regulating AQP9 expression and glycerol accumulation during the edema formation. Adult (400-425 g) male Sprague-Dawley rats received a closed head injury with a weight drop (450 g, 2-m height) and were allowed to survive up to 48 hours. Some rat groups were administered 2-methoxyestradiol (2ME2, a HIF-1alpha inhibitor) 30 minutes after injury and were euthanized at 4 and 24 hours after injury. Brain edema was measured directly by water content, and glycerol concentration was determined by the Cayman Glycerol Assay. HIF-1alpha and AQP9 protein levels were assessed by Western immunoblotting. This study demonstrated a significant (P<0·05) increase in brain water content at 4-48 hours following impact. Cerebral glycerol was significantly (P<0.05) up-regulated at as early as 1 hour and remained at high levels for up to 48 hours. Similarly, significant (P<0.05) increases in HIF-1alpha and AQP9 protein levels were found at 1 hour and up to 48 hours after injury. Compared to untreated but injured rats, inhibition of HIF-1alpha by 2ME2 significantly (P<0.05) reduced the TBI-induced AQP9 up-regulation. This reduction was temporally associated with significant (P<0.05) decreases in both edema and glycerol accumulation. The data suggested an associated induction of HIF-1alpha, AQP9, and extracellular glycerol accumulation in edema formation following diffuse TBI. The implication of HIF-1alpha and AQP9 underlying TBI-induced edema formation offers possibilities for novel TBI therapies.     

Posttraumatic reduction of edema with aquaporin-4 RNA interference improves acute and chronic functional recovery

Traumatic brain injury (TBI) is common in young children and adolescents and is associated with long-term disability and mortality. The neuropathologic sequelae that result from juvenile TBI are a complex cascade of events that include edema formation and brain swelling. Brain aquaporin-4 (AQP4) has a key role in edema formation. Thus, development of novel treatments targeting AQP4 to reduce edema could lessen the neuropathologic sequelae. We hypothesized that inhibiting AQP4 expression by injection of small-interfering RNA (siRNA) targeting AQP4 (siAQP4) after juvenile TBI would decrease edema formation, neuroinflammation, neuronal cell death, and improve neurologic outcomes. The siAQP4 or a RNA-induced silencing complex (RISC)-free control siRNA (siGLO) was injected lateral to the trauma site after controlled cortical impact in postnatal day 17 rats. Magnetic resonance imaging, neurologic testing, and immunohistochemistry were performed to assess outcomes. Pups treated with siAQP4 showed acute (3 days after injury) improvements in motor function and in spatial memory at long term (60 days after injury) compared with siGLO-treated animals. These improvements were associated with decreased edema formation, increased microglial activation, decreased blood–brain barrier disruption, reduced astrogliosis and neuronal cell death. The effectiveness of our treatment paradigm was associated with a 30% decrease in AQP4 expression at the injection site.     

甘氨酸通过抑制大鼠创伤性脑损伤后炎症反应来发挥神经保护作用

目的 探讨甘氨酸对创伤性脑损伤(TBI)大鼠的神经保护作用及机制。方法 将SD雄性大鼠随机分为对照(Sham)组、脑损伤+溶剂(TBI+Vehicle)组和脑损伤+甘氨酸(TBI+Glycine)组,采用Feeney's自由落体法建立创伤性脑损伤模型; 术后1 h侧脑室注射甘氨酸(2 mg/kg)或等体积的溶剂; 术后24 h,取脑组织样本; 采用脑含水量测定、蛋白免疫印迹法和免疫荧光法评价甘氨酸对大鼠TBI的神经保护作用; 采用ELISA法检测炎症因子白介素1β(IL-1β)、白介素6(IL-6)和肿瘤坏死因子α(TNF-α)的表达水平,评价甘氨酸对TBI后脑组织炎症反应的抑制作用。结果 甘氨酸可减轻TBI后脑水肿,减少皮层神经元损伤; 同时甘氨酸可抑制TBI后炎症因子IL-1β、IL-6和TNF-α的过度释放。结论 甘氨酸对大鼠TBI具有神经保护作用; 甘氨酸对TBI后相关炎症因子过度增高的抑制可能部分解释其神经保护作用机制。     

Intracerebral hemorrhage in mice: model characterization and application for genetically modified mice.

Gene knockout or transgenic animals may assist in elucidating the mechanisms of brain injury after intracerebral hemorrhage (ICH). However, almost all commercially available transgenic or knockout animals are mice. The purpose of this study was to develop an ICH model in mice and to investigate the influence of gender and complement C5 genetic differences on outcome after ICH. Male and female C57BL/6 mice and C5-deficient and -sufficient control mice were anesthetized and then received an injection of 30 microL autologous whole blood into the right basal ganglia. Brain water content was studied at 1 and 3 days after ICH. Behavioral tests (fore-limb use asymmetry and corner turn test) were performed at 1, 3, 7, 14, 21, or 28 days after ICH. In male mice, brain water content was significantly increased in the ipsilateral basal ganglia 1 and 3 days after ICH, compared with saline injection controls (P < 0.01). There were marked neurological deficits 1 and 3 days after ICH, with progressive recovery over 28 days. In contrast, although brain edema and behavioral deficits were similar at 1 day after ICH in female and male mice, female mice showed reduced edema at 3 days and a faster recovery of behavioral deficits after ICH. 17 beta-estradiol treatment in male mice markedly reduced ICH-induced edema (P < 0.01). Brain water content was significantly increased in C5-deficient mice compared with C5-sufficient at 3 days after ICH (P < 0.05). These findings suggest that the mouse ICH model is a reproducible and feasible model. These results also suggest that gender and complement C5 are factors affecting brain injury after ICH.     

大鼠重型颅脑损伤急性期水通道蛋白4的表达

目的探讨水通道蛋白（AQP4）在大鼠重型脑外伤急性期的表达变化及其与脑水肿间的关系。方法49只成年雄性SD大鼠,随机分为对照组及实验组（伤后4h、8h、12h、24h、5d共5组）。制作重度冲击加速性损伤模型,分别于伤后4h、8h、12h、24h、72h、5d采用干湿比重法测脑组织含水量,原子吸收分光光度法测定Na^＋、K^＋含量,Evans Blue（EB）测定法观察大鼠血-脑屏障（BBB）通透性变化,半定量逆转录聚合酶链反应（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4h开始表达上调,8h、12h依次增高,24h达到峰值（P〈0.05）,3d时仍维持较高水平,伤后5d有所降低。脑含水量、Na^＋含量的变化与AQP4 mRNA表达变化一致。经相关性分析,AQP4 mRNA的表达与脑含水量及脑EB含量均呈正相关（P〈0.05）。结论重型脑损伤急性期,AQP4 mRNA表达的变化与颅脑损伤后BBB的破坏及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。     

雪莲黄酮对大鼠创伤性脑水肿的治疗作用及其机制的初步研究

目的研究雪莲黄酮对大鼠创伤性脑水肿的治疗作用及其机制。方法采用液压冲击法制作大鼠脑创伤模型,用雪莲黄酮注射液进行治疗。治疗后不同时间取伤灶及其周围脑组织进行含水量和与脂质过氧化有关的一些指标进行检测。结果脑创伤后6h、24h及3d伤灶及其周围脑组织中含水量及丙二醛含量明显增加(P<0.01),而超氧化物岐化酶含量明显减少(P<0.01),但雪莲黄酮能逆转上述变化。结论雪莲黄酮对大鼠创伤性脑水肿有一定的治疗作用,作用机制可能与其抗脂质过氧化作用有关。     

维生素C在急性大剂量乙醇摄入后颅脑损伤中作用的研究

目的探讨维生素C（VitC）在急性大剂量乙醇摄入后颅脑损伤（TBI）后继发性脑损伤的作用及其可能机制。 方法将实验大鼠随机分为打击+生理盐水组（TBI+only）；打击+乙醇+生理盐水组（TBI+EtOH）；打击+VitC组（TBI+VitC）；打击+乙醇+VitC组（TBI+EtOH+VitC），每组10只。建立中度TBI模型，TBI后24 h进行神经功能损伤评分、脑含水量及伊文氏蓝含量测定；采用Western blot法测定TBI后24 h的损伤侧脑组织中细胞色素P450（CYP2E1），水通道蛋白-4（AQP-4），基质金属蛋白酶-9（MMP-9）和血脑屏障紧密连结蛋白（Occludin）的表达情况。 结果打击24 h后，TBI+EtOH组的神经功能损伤评分、脑含水量和伊文氏蓝含量明显增加，VitC干预后，各项指标明显减少，组间差异有统计学意义（P<0.05）；与TBI+EtOH组相比，TBI+EtOH+VitC组的CYP2E1表达减少，AQP-4和MMP-9的含量降低，Occludin的含量增高，组间差异有统计学意义（P<0.05）。 结论急性乙醇摄入加剧了TBI后细胞毒性脑水肿，而VitC可通过CYP2E1减少AQP-4和MMP-9的激活，增加Occludin蛋白的表达，减少血脑屏障紧密连接的分解及完整性的破坏，降低血脑屏障的开放并减轻脑水肿，最终改善神经功能。