黄体酮减轻大鼠蛛网膜下腔出血后早期脑损伤

目的 探讨黄体酮对蛛网膜下腔出血(SAH)后早期脑损伤(EBI)中细胞凋亡、血脑屏障(BBB)稳定性、脑水肿和死亡率方面的保护作用.方法 66只大鼠被随机分为假手术组、SAH+溶剂组、SAH+黄体酮组.于SAH模型制成后1h、6h和12h分别给予黄体酮(16毫克/千克体重)或等体积的溶剂.在SAH后24h分析不同组间大鼠在死亡率、神经功能评分、脑水肿、细胞凋亡、caspase-3及基质金属蛋白酶-9(MMP-9)表达水平的差异.结果 与SAH+溶剂组比较,黄体酮治疗显著降低了大鼠的死亡率、细胞凋亡程度以及caspase-3水平与MMP-9的表达水平,减轻了脑水肿和伊文思蓝的渗出,提高了神经功能评分.结论 黄体酮可通过抑制细胞凋亡和稳定BBB减轻SAH后EBI.     

虾青素对小鼠蛛网膜下腔出血早期脑损伤的保护机制的研究

目的研究虾青素对小鼠蛛网膜下腔出血(SAH)早期脑损伤的保护机制。方法 ICR雄性小鼠采用随机数字法随机分为四组:蛛网膜下腔出血组、假手术组、蛛网膜下腔出血+溶剂组(DMSO)、蛛网膜下腔出血+虾青素组。通过建立小鼠视交叉注血方法建立蛛网膜下腔出血模型,于手术后24 h记录神经功能评分,并应用末端脱氧核苷酸转移酶介导的生物素脱氧尿嘧啶核苷酸缺口末端标记法(TUNEL)、western blot法检测脑组织中的NOX2蛋白含量、ELISA法检测TNF-a/IL-1β水平,干湿法检测脑组织中含水量。结果与对照组相比,SAH后小鼠神经功能损伤评分加重,脑水肿加重,脑组织中的NOX2蛋白及脑组织中凋亡阳性细胞数也显著增多,TNF-a/IL-1β值明显升高;应用虾青素干预以后,小鼠神经功能改善,脑组织凋亡阳性细胞明显减少。同时,虾青素能够降低SAH后小鼠脑组织中NOX2蛋白,TNF-a/IL-1β水平值也明显降低。结论虾青素对s AH后早期脑损伤(EBI)具有保护作用,其作用机制可能与其抗氧化性有关。     

虾青素对小鼠蛛网膜下腔出血早期脑损伤的保护机制的研究

目的 研究虾青素对小鼠蛛网膜下腔出血（SAH）早期脑损伤的保护机制。方法 ICR雄性小鼠采用随机数字法随机分为四组：蛛网膜下腔出血组、假手术组、蛛网膜下腔出血+溶剂组（DMSO）、蛛网膜下腔出血+虾青素组。通过建立小鼠视交叉注血方法建立蛛网膜下腔出血模型,于手术后24 h记录神经功能评分,并应用末端脱氧核苷酸转移酶介导的生物素脱氧尿嘧啶核苷酸缺口末端标记法（TUNEL）、western blot法检测脑组织中的NOX2蛋白含量、ELISA法检测TNF-a/IL-1β水平,干湿法检测脑组织中含水量。结果 与对照组相比,SAH后小鼠神经功能损伤评分加重,脑水肿加重,脑组织中的NOX2蛋白及脑组织中凋亡阳性细胞数也显著增多,TNF-a/IL-1β值明显升高;应用虾青素干预以后,小鼠神经功能改善,脑组织凋亡阳性细胞明显减少。同时,虾青素能够降低SAH后小鼠脑组织中NOX2蛋白,TNF-a/IL-1β水平值也明显降低。结论 虾青素对sAH后早期脑损伤（EBI）具有保护作用,其作用机制可能与其抗氧化性有关。     

信号转导与蛛网膜下腔出血早期脑损伤

蛛网膜下腔出血(subarachnoid hemorrhage,SAH)是一种破坏性脑血管疾病,导致高死亡率和致残率,在临床上,大多数死亡发生在SAH发病后的几个小时以内,并且许多幸存者遗留认知缺陷,永久影响其功能状态和生活质量.     

动脉瘤破裂自发性蛛网膜下腔出血后的早期脑损伤

蛛网膜下腔出血（SAH）后的早期脑损伤（EBI）指的是从初次出血那刻起到血管痉挛发生之前大脑内发生的一系列改变。最新研究认为,EBI可能才是SAH患者的主要死亡原因。它通过各种途径,包括缺血途径、凋亡途径、炎症途径等,导致细胞的死亡,血脑屏障（BBB）的破坏,脑水肿和神经元的直接损伤。未来针对EBI的治疗将为SAH患者提供一个可行性的选择。     

大鼠蛛网膜下腔出血后早期脑损伤模型的建立

目的 建立一种微创、重复性好的大鼠蛛网膜下腔出血后早期脑损伤动物模型.方法 采用视交叉前池注血法建立蛛网膜下腔出血( SAH)后早期脑损伤(EBI)动物模型.在脑立体定位仪引导下将导管插入视交叉前池,注入300μl自体动脉血建立SAH后EBI模型.进行神经功能学评分,采用激光多普勒血流量仪(LDF)测定局部脑血流量(rCBF),解剖观察前循环周围血液分布情况,应用透射电子显微镜观察海马区神经细胞超微结构变化.结果 大部分大鼠在SAH后有神经行为学异常,48 h后逐渐恢复正常.SAH后不同时间点的rCBF均低于对照组.模型组大鼠颅脑解剖发现前循环蛛网膜下腔有大量的血液和血凝块.透射电子显微镜观察:与对照组比较,SAH组神经细胞线粒体和内质网肿胀,核染色质凝聚、趋边.结论 此动物模型稳定可靠,重复性高,适合进行临床前循环动脉瘤性蛛网膜下腔出血后早期脑损伤病理生理研究.     

芍药苷对蛛网膜下腔出血早期脑损伤大鼠NLRP3炎性小体表达的影响

目的 探究芍药苷(Paeoniflorin,PAE)对蛛网膜下腔出血(Subarachnoid hemorrhage,SAH)早期脑损伤大鼠NLR家族Pyrin域蛋白3(NLR family Pyrin domain containing 3,NLRP3)炎性小体表达的影响。方法 将60只大鼠随机分为假手术(Sham)组、模型(SAH)组、芍药苷低剂量(PAE-L)组、芍药苷高剂量(PAE-H)组; Sham组不刺破血管,其余各组采用血管内穿孔法构建SAH大鼠模型; PAE-L组、PAE-H组腹腔注射对应剂量的芍药苷(10、20 mg/kg),Sham组、SAH组腹腔注射等量0.9%氯化钠溶液,2次/d,共3 d; 采用Garcia评分法评估大鼠神经功能; SAH评分法评估蛛网膜下腔出血情况; 脑组织含水量测定评估脑水肿; 伊文思蓝(Evans blue,EB)染色评估血脑屏障通透性; 苏木精-伊红(Hematoxylin-eosin,HE)染色观察大鼠脑组织病理损伤; TdT介导的dUTP末端标记法(TdT-mediated dUTP nick-end labeling,TUNEL)染色检测神经元凋亡; 免疫荧光染色检测NLRP3、离子钙结合衔接分子-1(Ionized calcium binding adapter molecule-1,Iba-1)和髓过氧化物酶(Myeloperoxidase,MPO)表达水平; 免疫组化染色检测NLRP3、凋亡相关斑点样蛋白(Apoptosis-associated speck-like protein containing CARD,ASC)、半胱氨酸天冬氨酸酶-1(Cysteinyl aspartate-specific proteinase,Caspase-1)表达水平; Western Blot检测B细胞淋巴瘤-2(B cell lymphoma-2,Bcl-2)、Bcl-2相关X的蛋白质(Bcl-2-Associated X protein,Bax)、Caspase-3,NLRP3,ASC,Caspase-1、白介素-1β(Interleukin-1 β,IL-1β)、IL-18、肿瘤坏死因子-α(Tumor necrosis factor-α,TNF-α)、Iba-1和MPO表达水平。采用氧化血红蛋白(Oxygenated hemoglobin,OxyHb)构建原代皮层神经元体外SAH模型,并将其分为对照(Control)组、模型(OxyHb)组、芍药苷低剂量(PAE-L)组和芍药苷高剂量(PAE-H)组; Control组正常培养,OxyHb组、PAE-L组、PAE-H组神经元在含20 uM OxyHb的神经元培养基中培养,PAE-L组、PAE-H组分别加入对应剂量的芍药苷(10、20 uM); 各组神经元孵育48 h; 采用细胞计数试剂盒8(Cell counting kit 8,CCK8)法和TUNEL染色检测神经元活性及凋亡; Western Blot检测Bcl-2,Bax,Caspase-3的表达水平。结果 动物模型显示,Sham组大鼠脑组织未见积血,脑组织细胞结构清晰可辨; 与Sham组比较,SAH组脑组织可见大量积血,脑组织细胞排列松散,Garcia评分降低(P<0.05),SAH评分、脑含水量、EB渗出量升高(P<0.05),神经元TUNEL阳性细胞数增加(P<0.05),Bcl-2表达水平降低,Bax,Caspase 3,NLRP3,ASC,Caspase-1,IL-1β,IL-18,TNF-α表达水平升高(P<0.05),Iba-1和MPO阳性细胞数增加(P<0.05); 与SAH组比较,PAE-L组、PAE-H组脑组织积血减少,脑组织细胞状态趋于正常,Garcia评分升高(P<0.05),SAH评分、脑含水量、EB渗出量降低(P<0.05),神经元TUNEL阳性细胞数减少(P<0.05),Bcl-2表达水平升高,Bax,Caspase 3,NLRP3,ASC,Caspase-1,IL-1β,IL-18,TNF-α表达水平降低(P<0.05),Iba-1和MPO阳性细胞数减少(P<0.05)。细胞模型显示,Control组神经元形态正常; 与Control组比较,OxyHb组神经元肿胀,突触丧失,神经元活性降低,凋亡率增高(P<0.05),Bcl-2表达水平降低,Bax,Caspase 3表达水平升高(P<0.05); 与OxyHb组比较,PAE-L组、PAE-H组细胞损伤减轻,神经元活性升高,凋亡率降低(P<0.05),Bcl-2表达水平升高,Bax,Caspase 3表达水平降低(P<0.05)。结论 芍药苷能够减轻SAH后大鼠脑水肿、细胞凋亡和神经损伤,其机制可能为通过抑制NLRP3炎性小体的激活,并抑制小胶质细胞和中性粒细胞浸润,改善SAH后早期脑损伤。     

硫氧还蛋白相互作用蛋白表达下调减轻大鼠蛛网膜下腔出血后早期脑损伤

目的观察大鼠蛛网膜下腔出血(subarachnoid hemorrhage,SAH)后早期硫氧还蛋白相互作用蛋白(thioredoxin-interacting protein,TXNIP)表达变化,检测干预前后TXNIP及下游凋亡因子表达,探讨TXNIP参与SAH后早期脑损伤(early brain injury,EBI)的可能机制。方法血管内穿刺法建立SAH模型。97只成年雄性SD大鼠,随机分为假手术对照组(Sham组,17只)、SAH组(32只)、Control si RNA组(12只)、TXNIP si RNA组(12只)、白藜芦醇(resveratrol,RES)对照组(12只)、RES干预组(12只)。Western blot检测SAH后各时间点及干预前后TXNIP、p-ASK-1、Caspase-3表达变化,荧光共聚焦检测TXNIP在神经元定位,TUNEL法检测细胞凋亡与TXNIP共定位,同时进行脑水肿评估(6只/组)和行为学评分(12只/组)。结果采用TXNIP si RNA和TXNIP抑制剂RES干预后死亡率、行为学评分及脑水肿(F=7.964,P0.05)得到改善。荧光共聚焦显示TXNIP在大鼠脑神经元广泛表达,且主要位于胞浆。荧光TUNEL提示TXNIP与皮层区及海马区凋亡细胞共定位。Western blot发现与Sham组(0.476±0.043,n=3)比较,TXNIP在SAH后12h(0.729±0.548)表达逐渐增高,72h(1.509±0.071)仍处于较高水平,同时伴随下游凋亡因子的增高,差异有统计学意义(F=7.806,P0.05)。采用TXNIP si RNA和TXNIP抑制剂RES干预后,TXNIP表达下调(F=900.849,P0.05,n=3),下游凋亡因子出现下降(p-ASK1,F=32.897,P0.05;Caspase-3,F=89.120,P0.05)。结论大鼠SAH后早期TXNIP表达增加,通过其促凋亡机制参与EBI发生,下调TXNIP能减轻大鼠SAH后EBI,这可能为临床SAH早期治疗提供新的治疗思路。     

Neuritin attenuates early brain injury in rats after experimental subarachnoid hemorrhage

Objectives: Early brain injury (EBI) is central to the pathological progress of subarachnoid hemorrhage (SAH). In this study, we determined if neuritin protects the brain against EBI in rats and discussed the role of apoptosis pathway mediated by endoplasmic reticulum stress in this neuroprotective route. Methods: A total of 96 male Sprague Dawley rats were divided into control, sham, SAH and SAH + neuritin groups. The rat SAH model was induced by injection 0.3 mL of nonheparinized arterial blood into the prechiasmatic cistern. Mortality assay, neurological scores, brain water content measurement, Evans blue dye assay, TUNEL stain assay and Western blot analysis were performed. Results: Neuritin significantly improved the neurological scores, brain water content, blood-brain barrier (BBB) and apoptosis compared with the control and sham groups within 24 h after SAH. TUNEL staining assay results demonstrated that apoptosis was ameliorated, MMP-9 expression was reduced, whereas GRP78, CHOP, caspase-12 and ASK1 levels were markedly preserved after neuritin application. Conclusions: Our study demonstrated that neuritin plays a neuroprotective role on EBI after SAH by attenuating BBB disruption, brain edema and apoptosis.     

4＇，5，7-三羟基异黄酮对蛛网膜下腔出血大鼠的神经保护和抗氧化作用研究

目的探讨4＇,5,7-三羟基异黄酮对蛛网膜下腔出血（SAH）后的神经保护作用。方法对大鼠单次枕大池注血模型分别以10mg／kg、50mg／kg浓度腹腔注射4＇,5,7-三羟基异黄酮,观察大鼠脑水肿、血脑屏障（BBB）的通透性、氧化应激和血红素氧合酶-1（HO-1）的变化情况。结果4＇,5,7-羟基异黄酮可以减轻SAH后脑水肿,降低BBB通透性、缓解氧化应激状态及减少HO-1的表达。结论4＇,5,7-三羟基异黄酮可能是通过提高内源性抗氧化酶的表达和抑制自由基的产生,从而在SAH中产生神经功能保护作用。     

蛛网膜下腔出血后早期海马ADAMTS-1的表达与血脑屏障通透性的相关性研究

目的研究大鼠蛛网膜下腔出血(subarachnoid hemorrhage,SAH)后早期海马组织中ADAMTS-l(a disintegrin-like and metalloproteinase with thrombospondin type l motifs)表达情况及其与血脑屏障通透性的关系,初步探讨ADAMTS-l在实验性大鼠SAH后早期脑损伤(early brain injury,EBI)中的作用。方法成年雄性SD大鼠108只,分假手术组和SAH组。采用大鼠视交叉前池注血模型,于SAH后6、12、24、48、72 h时间点,应用Western-Blotting和RT-PCR法检测大鼠海马ADAMTS-1蛋白及mRNA表达变化,同时应用甲酰胺浸泡法检测大鼠脑内伊文氏蓝(Evans blue,EB)含量。结果大鼠SAH后6 h、12 h组海马ADAMTS-1mRNA及蛋白表达与sham组相比无统计学意义,于出血后24 h表达明显升高,48 h达到高峰,72 h后仍维持在较高水平。脑内伊文氏蓝含量亦于出血后24 h明显升高,48 h达到高峰并于72 h仍维持在较高水平。ADAMTS-1蛋白表达与脑内EB含量成正相关(r=0.936,P=0.014)。结论大鼠SAH后早期脑损伤过程中ADAMTS-l的表达与血脑屏障损伤成正相关,提示ADAMTS-l可能参与SAH后早期脑损伤的病理过程。     

C3G通过PKA/CREB信号通路减轻成年小鼠SAH后早期脑损伤

目的 探讨矢车菊素-3-O-葡萄糖苷(C3G)对小鼠蛛网膜下腔出血(SAH)后早期脑损伤(EBI)的影响及作用机制。方法 取72只雄性C57小鼠随机分成6组:假手术组、SAH组、溶剂组、低剂量C3G组(10 mg/kg)、中剂量C3G组((20 mg/kg)、高剂量C3G组(30 mg/kg);每组12只。应用颈动脉穿刺法制作小鼠SAH模型,术后24 h进行Garcia评分和平衡木评分评估神经功能;每组小鼠随机取6只取外周血检测活性氧(ROS)和丙二醛(MDA)含量,然后取出完整脑组织进行SAH出血评分、脑水含量检测;每组剩余6只小鼠取外周血检测GSH/GSSG水平,然后取脑组织应用免疫印迹法检测PKA、p-PKA、CREB、p-CREB和GCLC表达水平。结果 与假手术组相比,SAH组小鼠神经功能评分明显下降(P<0.05),脑水含量、SAH出血评分、外周血ROS和MDA含量均显著增加(P<0.05),外周血GSH/GSSG比值明显下降(P<0.05),脑组织p-PKA、p-CREB和GCLC表达明显上调(P<0.05)。C3G明显增加小鼠神经功评分(P<...     

[Gly14]-Humanin减轻大鼠颅脑外伤后氧化应激及细胞凋亡

目的探讨[Gly14]-Humanin(HNG)对大鼠颅脑外伤后脑组织超氧化物歧化酶(SOD)、丙二醛(MDA)、谷胱甘肽(GSH)和细胞凋亡的影响。方法 135只SD大鼠分为空白组(n=45)、对照组(n=45)及HNG组(n=45),其中对照组及HNG组建立颅脑外伤模型后前者予右侧股静脉注射生理盐水2 m L/kg,后者则予HNG 2μL/kg,此后各组每24 h予1次等量生理盐水/HNG,直至大鼠被处死;而空白组不予任何处理。根据处死时间随机分为1 h、3 d和7 d共3个亚组,每亚组各15只。比较损伤灶周围脑组织MDA、SOD、GSH含量水平及细胞凋亡情况。结果 HNG组大鼠脑组织中MDA含量水平及凋亡细胞计数在损伤后1 h即升高,3 d达到最高值,后开始降低,但7 d时仍高于损伤后1 h水平,均显著低于同一时间点的对照组及空白组(P均0.05);相反,SOD活性在损伤后迅速降低,3 d达到最低值,随后逐渐上升,但7 d时仍低于损伤后1 h水平,均显著高于同一时间点的对照组及空白组(P均0.05);GSH变化规律与SOD基本一致,与各时间点的对照组比较亦有显著性(P均0.05);HNG大鼠脑组织损伤后MDA含量水平与细胞凋亡数呈正相关(r=0.720,P0.05),而SOD及GSH的含量与细胞凋亡数呈负相关(r=-0.702,P0.05;r=-0.674,P0.05)。结论颅脑外伤后HNG抑制氧化应激反应,进一步减少细胞凋亡,从而发挥神经保护作用。     

Anti-apoptotic and neuroprotective effects of Tetramethylpyrazine following subarachnoid hemorrhage in rats

This study was designed to explore the effects of Tetramethylpyrazine on cerebral vasospasm and early brain injury and its underlying mechanisms after experimental SAH in rats. Male Sprague-Dawley rats (n=164) were allocated randomly to SAH+TMP, SAH+vehicle (sodium chloride), or sham-operated group. The SAH model was induced through perforating internal carotid artery. TMP (30 mg/kg) or the vehicle was injected via vena caudalis 60 min before the perforation. Mortality, neurological scores, water content of brain and cerebral vasospasm were recorded at 24 h after SAH. Apoptosis of cerebral cortex was determined by TUNEL staining; caspase-3, bax and bcl-2 by Western blotting; P53 expression by immunohistochemical staining. TMP administrated in advance improved neurological scores, ameliorated cerebral edema and cerebral vasospasm. TUNEL-positive cells were reduced significantly in TMP-treated group. P53 was not found significantly different between TMP-treated and vehicle-treated group, while P53 positive cells were markedly higher in SAH group than that in sham-operated group. Cleaved caspase-3 protein was decreased significantly in TMP-treated group, while bax, bcl-2 protein expression did not differ statistically among the three groups. In conclusion, TMP ameliorated cerebral vasospasm and early brain injury after experimental SAH in rats. The underlying mechanisms may be partly related to inhibition of caspase-3 dependent proapoptosis pathway.     

Role of endothelial nitric oxide synthase for early brain injury after subarachnoid hemorrhage in mice

The first few hours and days after subarachnoid hemorrhage (SAH) are characterized by cerebral ischemia, spasms of pial arterioles, and a significant reduction of cerebral microperfusion, however, the mechanisms of this early microcirculatory dysfunction are still unknown. Endothelial nitric oxide production is reduced after SAH and exogenous application of NO reduces post-hemorrhagic microvasospasm. Therefore, we hypothesize that the endothelial NO-synthase (eNOS) may be involved in the formation of microvasospasms, microcirculatory dysfunction, and unfavorable outcome after SAH. SAH was induced in male eNOS deficient (eNOS^–/–) mice by endovascular MCA perforation. Three hours later, the cerebral microcirculation was visualized using in vivo 2-photon-microscopy. eNOS^–/– mice had more severe SAHs, more severe ischemia, three time more rebleedings, and a massively increased mortality (50 vs. 0%) as compared to wild type (WT) littermate controls. Three hours after SAH eNOS^–/– mice had fewer perfused microvessels and 40% more microvasospasms than WT mice. The current study indicates that a proper function of eNOS plays a key role for a favorable outcome after SAH and helps to explain why patients suffering from hypertension or other conditions associated with impaired eNOS function, have a higher risk of unfavorable outcome after SAH.     

蛛网膜下腔出血后早期脑损伤的研究进展

蛛网膜下腔出血(SAH)是由多种脑血管疾病引起的一种复杂的临床综合征,可对中枢神经系统产生灾难性打击,其高致残率、病死率显著影响了患者的神经认知功能恢复,加重家庭和社会经济负担。其中颅内动脉瘤破裂出血是SAH最常见的病因(85%)。近年来,多项研究表明早期脑损伤(EBI)是导致蛛网膜下腔出血预后不良的重要因素。脑表面或脑底部血管破裂后,血液进入蛛网膜下腔的血液引起机体强烈的神经炎症反应,表现为小胶质细胞活化,外周免疫细胞募集,微循环障碍,血脑屏障破坏和神经细胞凋亡。本研究总结了目前已知的有关EBI的病理生理机制,同时讨论了蛛网膜下腔出血后EBI的潜在治疗靶点。     

氧化应激在大鼠液压冲击性脑损伤中的时程变化和意义

目的观察大鼠液压冲击脑损伤活性氧族(ROS)、丙二醛(MDA)、超氧化物歧化酶(SOD)以及血红素氧化酶1(HO-1)和磷酸酰胺腺嘌呤二核苷酸醌氧化还原酶1(NQO-1)表达变化,探讨氧化应激在大鼠液压冲击性脑损伤中的时程变化和意义。方法成年雄性SD大鼠56只,制作液压冲击颅脑损伤模型,分别于术后1h、6h、12h、24h、3d、7d采用分光光度法及酶学法检测ROS生成、MDA含量以及SOD活性;用干湿重法、Western blot分别测定水肿脑组织含水量及HO-1和NQO-1蛋白表达。结果与假手术组(SO组)比较,损伤组(TBI组)ROS于1h开始增加,6h急剧增加,12h达到峰值;SOD活性24h下降到最低值,MDA于24h达到峰值;HO-1和NQO-1蛋白表达均于6h开始增高,24h达到高峰,3d后降低(P0.05)。结论氧化应激性脑损伤在大鼠颅脑液压冲击伤中起着重要作用,早期调控氧化应激状态有助于减轻继发性脑损伤。     

Long-term cognitive dysfunction following experimental subarachnoid hemorrhage: new perspectives

Cognitive dysfunction is increasingly recognized as a significant long-term complication following subarachnoid hemorrhage (SAH), affecting up to 60% of survivors. We proposed to determine the incidence and explore potential mechanisms of cognitive dysfunction in a rat model. The effects of intracisternal blood, saline and sham injections were compared. At five weeks, Morris water maze escape latency (P = 0.001) and swimming distance (P = 0.001) were significantly different between groups, with increased latencies and distances recorded in the blood group in spite of increased swimming speed. The number of morphologically intact cortical (r = − 0.75, P = 0.0001) and hippocampal CA1 (r = − 0.80, P < 0.0001) neurons correlated with escape latency. In spite of only slight early reductions in proximal cerebral arterial diameters, pronounced and prolonged reductions in regional cerebral blood flow were observed in SAH rats, suggesting microvascular dysfunction. In concordance, cerebral microangiographic perfusion remained incomplete even after 2 weeks. 8-hydroxydeoxyguanosine immunohistochemistry also revealed microvascular as well as neuronal oxidative DNA damage. These results provide new insights into the pathogenesis of cognitive dysfunction in SAH. They reveal a surprisingly prolonged time course of diffuse cerebrovascular insufficiency, most likely due to reversible microvascular dysfunction. Similar to findings in experimental models of vascular dementia, the data indicate a potentially important role for prolonged cerebrovascular insufficiency, probably due to microvascular dysfunction, and selective cortical and subcortical neuronal loss in cognitive failure following SAH.     

Nuclear receptor nur77 promotes cerebral cell apoptosis and induces early brain injury after experimental subarachnoid hemorrhage in rats

Nur77 is a potent proapoptotic member of the nuclear receptor superfamily that is expressed predominantly in brain tissue. It has been demonstrated that Nur77 mediates apoptosis in multiple organs. Nur77‐mediated early brain injury (EBI) involves a conformational change in BCL‐2 and triggers cytochrome C (cytoC) release resulting in cellular apoptosis. This study investigates whether Nur77 can promote cerebral cell apoptosis after experimentally induced subarachnoid hemorrhage (SAH) in rats. Sprague Dawley rats were randomly assigned to three groups: 1) untreated group, 2) treatment control group, and 3) SAH group. The experimental SAH group was divided into four subgroups, corresponding to 12 hr, 24 hr, 48 hr, and 72 hr after experimentally induced SAH. It remains unclear whether Nur77 can play an important role during EBI after SAH as a proapoptotic protein in cerebral cells. Cytosporone B (Csn‐B) was used to demonstrate that Nur77 could be enriched and used to aggravate EBI after SAH. Rats treated with Csn‐B were given an intraperitoneal injection (13 mg/kg) 30 min after experimentally induced SAH. We found that Nur77 promotes cerebral cell apoptosis by mediating EBI and triggering a conformational change in BCL‐2, resulting in cytoC release. Nur77 activity, along with cerebral cell apoptosis, peaked at 24 hr after SAH onset. After induction of SAH, an injection of Csn‐B, an agonist for Nur77, enhanced the expression and function of Nur77. In summary, we have demonstrated the proapoptotic effect of Nur77 within cerebral cells, an effect that can be further exacerbated with Csn‐B stimulation. © 2014 Wiley Periodicals, Inc.