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1.
目的探讨早期缺氧缺血性脑病(HIE)动物模型弥散加权像(DWI)变化和热休克蛋白(HSP)70表达的演变规律。方法3日龄新生猪19只随机分为正常对照组、假手术组、缺氧缺血组。用1.5T磁共振仪行DWI和T2WI检查;用表观弥散系数(ADC)图,测量病灶中心区和周边区ADC值;应用SP法计数中心区和周边区HSP70阳性细胞。结果缺氧缺血组出现四肢抽搐、角弓反张等体征。缺氧缺血后3 h DWI有高信号,ADC图有低信号。各组中心区与周边区ADC比较有显著差异(P<0.01)。缺氧缺血后3 h出现HSP70阳性细胞,6 h达高峰,之后逐渐下降,各组中心区和周边区HSP70阳性细胞计数比较有极显著差异(P<0.01)。结论DWI结合ADC值可以敏感而准确地显示HIE病灶;HSP70表达提示早期HIE病灶周边区有可逆的脑组织区域。  相似文献   

2.
目的:目前,有关水在细胞内外或跨过血脑屏障的转运机制尚不清楚。水通道蛋白4(AQP4)是水通道蛋白家族中在脑表达最丰富的一个亚型,该文旨在探讨新生大鼠脑缺氧缺血后AQP4表达的改变及其与磁共振(MR)显示的脑水肿的关系。方法:7日龄新生大鼠24只,在缺氧前,缺氧后0h,1h和24h行MR扫描获得T2加权成像和表面弥散系数(ADC),应用免疫组化染色观察脑内AQP4表达和血脑屏障通透性的改变,并用蛋白质印迹行AQP4半定量分析。结果:缺氧后0h,整个缺血半球ADC值明显下降,缺氧后1h时ADC部分恢复,缺氧后24h时ADC改变与1h时类似。缺氧后缺血半球T2值增高,其动态变化类似ADC变化。缺氧后0h时可见IgG渗出脑血管外,随着缺氧后时间延长,IgG渗出逐渐加重。缺氧后缺血半球AQP4免疫染色减弱,其变化在缺氧后各时间点与ADC和T2改变相对应。蛋白质印迹分析显示仅缺氧后24h时AQP4减少。结论:新生大鼠脑缺氧缺血后AQP4表达减少,其减少可能参与了急性缺氧缺血性脑水肿的形成。缺氧后AQP4表达的快速减少可能与AQP4蛋白质构像改变或分布异位有关。  相似文献   

3.
水通道蛋白4在感染性脑水肿大鼠脑组织中变化的意义   总被引:1,自引:0,他引:1  
目的观察内毒素致幼年大鼠感染性脑水肿后脑组织水通道蛋白4(AQP4)表达的变化。方法将50只幼鼠随机分为内毒素组(40只)和对照组(10只)。建立内毒素致大鼠感染性脑水肿模型。于术后6、12、24、48 h处死动物,分别行脑组织含水量、血脑屏障通透率测定,以伊文思兰含量判定血脑屏障通透率,并应用免疫组织化学技术检测脑组织内AQP4表达水平。结果内毒素组脑组织含水量和伊文思兰(EB)水平明显高于对照组。在脂多糖注射后6 h时,幼鼠脑组织AQP4表达明显增加,12 h时达高峰,各时间点与对照组比较均有显著性差异(P<0.01)。结论感染性脑水肿后脑组织AQP4表达增加,且与脑组织含水量呈正相关。  相似文献   

4.
目的 观察水通道蛋白4mRNA(aquaporin-4,AQP-4mRNA)在新生鼠缺氧缺血损伤脑组织的表达,探讨其变化及与脑水肿发生的可能关系。方法 健康7日龄SD大鼠共240只,随机分为对照组120只和缺氧缺血性脑损伤模型组(HIBD组)120只。HIBD组经右侧颈总动脉结扎后,吸入8%O21h,建立HIBD模型。对照组仅行假手术,不予颈总动脉结扎和缺氧。两组均于HIBD模型制成后0、6、24、48h和72h分别处死动物(各时间点动物24只),进行脑含水量观察,ReahimePCR检测脑组织AQP4mRNA表达。结果 HIBD组6、24、48h和72h脑组织含水量均较对照组增加,差异有统计学意义(P〈0.05);与对照组比较,HIBD组脑组织AQP4mRNA表达在48h内呈下降趋势,72h出现恢复,但仍低于对照组(P〈0.05)。结论 AQP4mRNA在脑组织表达下降可能与脑水肿的发生有关,我们推测AQP4可能参与了HIBD时脑水肿的调节机制。  相似文献   

5.
目的 探讨新生大鼠缺氧缺血性脑损伤(HIBD)的发生机制.方法 建立新生大鼠HIBD模型,随机分为假手术组及HIBD 6 h、12 h、24 h、48 h、72 h组,每组6只.观察脑组织大体病理学改变.采用Real-time Q-PCR方法测定大鼠脑组织MMP-9 mRNA和TIMP-1 mRNA表达.结果 (1)新生大鼠HIBD后12~48 h脑水肿明显,可见点状软化坏死灶.(2)假手术组大鼠MMP-9 mRNA表达水平极低,HIBD组大鼠在缺氧缺血6 h表达开始增高,24 h达高峰,此后渐渐下降,但72 h仍维持较高的水平,与假手术组相比差异有非常显著性(P<0.01).(3)假手术组大鼠TIMP-1 mRNA表达水平极低,HIBD组大鼠在经历缺氧缺血6、12、24h,TIMP-1 mRNA表达水平有微弱升高,与假手术组相比差异有显著性(P<0.05),但48 h后TIMP-1 mRNA表达下降到假手术组水平(P>0.05).(4)MMP-9 mRNA/TIMP-1 mRNA比值在假手术组接近1:1,HIBD组缺氧缺血12 h后比值升高,在48 h达到高峰,72 h有所下降,但仍高于假手术组(P<0.01).结论 新生大鼠HIBD后可诱导MMP-9 mRNA表达,而MMP-9 mRNA和TIMP-1 mRNA表达的失衡可能参与了HIBD的发病过程.  相似文献   

6.
目的探讨缺血后处理(IPostc)对新生大鼠缺氧缺血性脑损伤(HIBD)可能的神经保护作用及其机制。方法以7日龄SD大鼠为研究对象,随机分为假手术组、HIBD组、IPostcⅠ组(15 s再灌注/15 s夹闭×3个循环)及IPostcⅡ组(30 s再灌注/10 s夹闭×3个循环),每组根据缺氧缺血后时间分为0、6、12、24 h及48 h 5个亚组,每个亚组15只。应用右侧颈总动脉夹闭联合低氧(8%O2+92%N2)建立HIBD模型,监测脑组织形态学变化,比较超氧化物歧化酶(SOD)、丙二醛(MDA)、脑组织含水量及水通道蛋白4(AQP4)mRNA相对表达量随时间的变化规律。结果经缺氧缺血处理的大鼠均出现典型的神经行为学异常、形态学和生化指标的变化。IPostcⅠ组SOD活性显著改善,MDA含量降低,脑组织含水量及AQP4 mRNA相对表达量降低,在6 h以后作用显著,差异有统计学意义(P<0.05)。而IPostcⅡ组无明显改善作用。结论缺血后处理对新生大鼠HIBD具有一定的神经保护作用,其机制与减轻氧化应激损伤及脑水肿有关。  相似文献   

7.
目的 研究Rho GDP解离抑制因子(Rho GDP dissociation inhibitor 2,RhoGDI2)mRNA 及Bcl-2 mRNA的表达在缺氧缺血性脑损伤(hypoxic-ischemic brain damage,HIBD)中的作用和机制.方法 30只新生7日龄SD大鼠按照完全随机化方法分为假手术组及HIBD 6 h和48 h组,每组10只.采用流式细胞仪检测脑细胞凋亡情况,并用Real-time RT-PCR方法测定脑组织中RhoGDI2和Bcl-2mRNA表达水平.结果 (1)新生大鼠HIBD后48h结扎侧大脑半球脑水肿明显.(2) HIBD6 h出现典型的凋亡细胞峰,细胞凋亡率为(1.40±0.12)%.HIBD 48 h凋亡峰更为明显,细胞凋亡率达到( 15.86±0.98)%.缺氧缺血后与假手术组相比,差异有统计学意义(P<0.01).(3)假手术组大鼠RhoGDI2和Bcl-2 mRNA表达水平较高(4.12±0.74、2.55±0.65),在HIBD 6 h后二者表达开始下降(3.19±0.77、1.96±0.36),48 h降低更加明显(1.04±0.18、1.06±0.17),与假手术组比较,HIBD各时间点RhoGDI2和Bcl-2 mRNA的表达均明显降低,差异有统计学意义(P<0.01).(4)缺氧缺m后各时间点RhoGDI2 mRNA的表达和Bcl-2 mRNA的表达呈正相关(r=0.831,P<0.05).结论 脑缺氧缺血后,随着凋亡的出现,RhoGDI2和Bcl-2 mRNA表达水平降低,提示Rh0GDI2表达失衡可能通过Bcl-2参与新生大鼠HIBD中凋亡的发生.  相似文献   

8.
本文探讨锌原卟啉(Znpp)对新生鼠缺氧缺血脑损伤的防治作用.将7日龄SD大鼠制备成缺氧缺血脑损伤(HIBD)新生鼠模型和Znpp治疗模型,并设假手术组作为对照.测定新生大鼠缺氧缺血(HI)后不同时间脑组织匀浆血红素氧化酶-1(HO-1)活性和环磷酸鸟苷(cGMP)以及血一氧化碳血红蛋白(COHb)含量,并在光镜及电镜下观察脑的病理学变化.结果显示,HI组在HI后1h、4 h、12 h HO-1活性、COHb及cGMP明显高于对照组(P<0.01);Znpp组的HO-1活性、COHb及cGMP明显低于HI组(P<0.01),但高于对照组(P<0.01).脑组织病理改变显示HI组呈明显的缺血缺氧性组织形态学改变,Znpp组的病理损伤明显减轻.结论HI后HO-1、CO和cGMP明显增高可加重脑组织损伤;而Znpp可通过抑制HO活性使CO和cGMP水平下降,可保护神经细胞,减轻脑缺氧缺血性损伤.  相似文献   

9.
目的观察脂多糖(LPS)致幼年大鼠感染性脑水肿后水通道蛋白4 mRNA(AQP4mRNA)的表达变化,探讨其作用机制。方法将50只幼鼠随机分为内毒素组(40只)和对照组(10只),内毒素组又按时间点分为6、12、24及48h4个亚组,每组均为10只。于预定时间点处死动物,制备脑组织标本。用干湿重法测定不同时间点脑组织含水量,甲酰胺法测定伊文思蓝(EB)水平,RT-PCR技术检测脑组织内AQP4 mRNA的表达。结果内毒素组脑组织含水量和EB水平明显高于对照组。LPS注射后6h,脑组织AQP4 mRNA水平的表达均明显增加,12h时达高峰,各时间点与对照组比较均有显著性差异(Pa〈0.01)。结论感染性脑水肿后脑组织中AQP4 mRNA的表达增加,且与血脑脊液屏障的破坏程度呈正相关。  相似文献   

10.
目的观察水通道蛋白4 mRNA(aquaporin-4,AQP-4 mRNA)在新生鼠缺氧缺血损伤脑组织的表达,探讨其变化及与脑水肿发生的可能关系。方法健康7日龄SD大鼠共240只,随机分为对照组120只和缺氧缺血性脑损伤模型组(HIBD组)120只。HIBD组经右侧颈总动脉结扎后,吸入8%O21h,建立HIBD模型。对照组仅行假手术,不予颈总动脉结扎和缺氧。两组均于HIBD模型制成后0、6、24、48h和72h分别处死动物(各时间点动物24只),进行脑含水量观察,RealtimePCR检测脑组织AQP-4 mRNA表达。结果HIBD组6、24、48h和72h脑组织含水量均较对照组增加,差异有统计学意义(P<0.05);与对照组比较,HIBD组脑组织AQP-4 mRNA表达在48h内呈下降趋势,72h出现恢复,但仍低于对照组(P<0.05)。结论AQP-4 mRNA在脑组织表达下降可能与脑水肿的发生有关,我们推测AQP-4可能参与了HIBD时脑水肿的调节机制。  相似文献   

11.
Edema formation can be observed using magnetic resonance imaging (MRI) in patients with stroke. Recent studies have shown that aquaporin-4 (AQP4), a water channel, is induced early after stroke and potentially participates in the development of brain edema. We studied whether induction of AQP4 correlated with edema formation in a rat pup filament stroke model using high field (11.7-Tesla) MRI followed by immunohistochemical investigation of AQP4 protein expression. At 24 h, we observed increased T2 values and decreased apparent diffusion coefficients (ADC) within injured cortical and striatal regions that reflected the edema formation. Coincident with these MR changes were significant increases in AQP4 expression on astrocytic end-feet in the border regions of injured tissues. Striatal imaging findings were still present at 72 h with a slow normalization of AQP4 expression in the border regions. At 28 d, AQP4 expression normalized in the border while in this region ADC values increased. We show that induction of AQP4 is increased during the period of active edema formation in the border region without regional correlation with edema. Finally, induction of AQP4 on astrocyte end-feet could participate in tissue preservation after ischemia in the immature rat brain.  相似文献   

12.

Background

Diffusion-weighted imaging is a valuable tool in the assessment of the neonatal brain, and changes in diffusion are seen in normal development as well as in pathological states such as hypoxic–ischemic encephalopathy (HIE). Various methods of quantitative assessment of diffusion values have been reported. Global ischemic injury occurring during the time of rapid developmental changes in brain myelination can complicate the imaging diagnosis of neonatal HIE.

Objective

To compare a quantitative method of histographic analysis of brain apparent coefficient (ADC) maps to the qualitative interpretation of routine brain MR imaging studies. We correlate changes in diffusion values with gestational age in radiographically normal neonates, and we investigate the sensitivity of the method as a quantitative measure of hypoxic–ischemic encephalopathy.

Materials and methods

We reviewed all brain MRI studies from the neonatal intensive care unit (NICU) at our university medical center over a 4-year period to identify cases that were radiographically normal (23 cases) and those with diffuse, global hypoxic–ischemic encephalopathy (12 cases). We histographically displayed ADC values of a single brain slice at the level of the basal ganglia and correlated peak (s-sDav) and lowest histogram values (s-sDlowest) with gestational age.

Results

Normative s-sDav values correlated significantly with gestational age and declined linearly through the neonatal period (r 2?=?0.477, P?<?0.01). Six of 12 cases of known HIE demonstrated significantly lower s-sDav and s-sDlowest ADC values than were reflected in the normative distribution; several cases of HIE fell within a 95% confidence interval for normative studies, and one case demonstrated higher-than-normal s-sDav.

Conclusion

Single-slice histographic display of ADC values is a rapid and clinically feasible method of quantitative analysis of diffusion. In this study normative values derived from consecutive neonates without radiographic evidence of ischemic injury are correlated with gestational age, declining linearly throughout the perinatal period. This method does identify cases of HIE, though the overall sensitivity of the method is low.  相似文献   

13.
??Abstract??Objective??The aim of this study was to evaluate the role of diffusion-weighted imaging ??DWI?? in the diagnosis of viral encephalitis and its relationship with the stage of the illness. Methods??We performed conventional magnetic resonance imaging ??MRI?? including T1WI?? T2WI sequences and DWI in 56 patients with viral encephalitis diagnosed on the basis of laboratory??clinical and radiologic findings??in which 29 patients were abnormal. Thirteen patients have received MRI two times. So ??there were 42 case-times of abnormal MRI.Based on the qualitative and quantitative comparison of the conventional MRI and DWI?? the patients were divided into three groups. Apparent diffusion coefficient ??ADC?? values of the involved and contralateral normal brain tissues were computed and compared for each group. Results ??In group ?? ??n = 23?? DWI was superior to conventional MRI in detecting the encephalitic involved sites and in depicting the borders of the encephalitic lesions. In group ?? ??n = 11?? DWI was similar to conventional MRI. In group ?? ??n = 8?? conventional MRI was superior to DWI. Mean ADC values of affected versus contralateral normal brain tissues were 0.45±0.19×10-3 mm2/s VS 0.93±0.06×10-3 mm2/s in group ??0.87±0.31×103 mm2/s VS 0.97±0.06×10-3 mm2/s in group ?? and 1.66±0.60×10-3 mm2/s VS 1.08±0.24×10-3 mm2/s in group ??. Patients in group ?? had significantly lower ADC values than those in group ?? while patients in group ?? had the highest ADC values ??P < 0.05??. The ADC values were significantly lower in the affected sites than in the unaffected sites of patients in groups I and ?? but were significantly higher in the affected sites than in the unaffected sites of patients in group ?? ??P < 0.05??. There was an excellent correlation between ADC values and duration of the disease ??r = 0.874??P = 0.01??. Conclusion??DWI is superior to other conventional diagnostic MR sequences in the detection of early viral encephalitic lesions and depiction of the lesion borders and?? in combination with other sequences?? DWI may contribute to the determination of the disease phase.  相似文献   

14.
目的 研究二氧化硫( SO2)对低氧性肺动脉高压大鼠肺动脉内源性硫化氢(H2S)/胱硫醚-γ-裂解酶( CSE)以及H2S/巯基丙酮酸转硫酶(MPST)体系的调节作用.方法 将雄性Wistar大鼠(32只)随机分为对照组、低氧组、低氧+ SO2组和低氧+天冬氨酸异羟肟酸(hydroxamate,HDX)组,每组8只.低氧处理采用常压低氧的方法,氧浓度为10%,每天低氧6h,持续21 d.对照组大鼠在常氧环境中饲养.低氧处理结束后采用右心导管法测定肺动脉平均压,采用硫电极法测定肺组织H2S含量和H2S产率,采用免疫组化法检测各组大鼠肺小动脉内膜及中膜CSE和MPST的蛋白表达.结果 低氧组大鼠肺动脉平均压较对照组高[(33.38 ±6.32) mm Hg vs(16.74±3.81) mm Hg,1 mm Hg=0.133 kPa,P<0.01];低氧+SO2组大鼠肺动脉平均压较低氧组低[(29.65±2.53)mm Hg vs(33.38±6.32) mm Hg,P<0.01],低氧+HDX组大鼠肺动脉平均压较低氧组高[(39.44±6.26) mm Hg vs(33.38±6.32) mm Hg,P<0.01].低氧组大鼠肺组织H2S含量[(2.02±0.43) μmol/g vs (3.11±0.42) μmol/g,P<0.01]及H2S产率[(19.64±3.48) nmol/(g· min)vs(28.20±5.95) nmol/(g·min),P<0.05]均较对照组低.给予SO2供体后,低氧+SO2组肺组织H2S含量[(2.73±0.20)μmol/g vs(2.02±0.43)μmol/g,P<0.01]及H2S产率[(26.24±1.92) nmol/(g· min)vs(19.64±3.48) nmol/(g· min),P<0.01]均较低氧组升高.当给予内源性SO2生成酶抑制剂HDX后,低氧+HDX组肺组织H2S含量[(1.64±0.23) μmol/g vs (2.02±0.43)μmol/g,P<0.05]及肺组织H2S产率[(13.94±3.63) nmol/(g·min) vs (19.64±3.48) nmol/(g·min),P<0.05]均较低氧组低.低氧组大鼠肺小动脉内膜[(0.31±0.02)vs(0.36±0.01),P<0.01]及中膜[(0.27±0.01)vs (0.30±0.01),P<0.01]中CSE蛋白表达均较对照组低.低氧+SO2组大鼠肺小动脉内膜CSE蛋白表达较低氧组高[(0.35±0.02) vs (0.31 ±0.02),P<0.01].低氧+HDX组大鼠肺小动脉内膜CSE蛋白表达较低氧组低[(0.26±0.01) vs (0.31±0.02),P<0.01].与对照组相比,低氧组大鼠肺小动脉内膜及中膜MPST的蛋白表达差异没有统计学意义.低氧+SO2组大鼠肺小动脉中膜MPST的蛋白表达较低氧组高[(0.32±0.02) vs (0.29±0.01),P<0.01];而与低氧组相比,低氧+ HDX组大鼠肺小动脉内膜及中膜MPST的蛋白表达差异没有统计学意义.结论 外源性给予SO2供体可上调低氧性肺动脉高压大鼠肺小动脉内膜H2S生成酶CSE及肺小动脉中膜MPST蛋白表达,促进H2S生成增多,从而间接缓解低氧性肺动脉高压的形成.  相似文献   

15.
目的 研究基质金属蛋白酶-9(matrix metalloproteinase-9,MMP-9)mRNA及紧密连接(tightjunction,TJ)蛋白occludin mRNA的表达在缺氧缺血性脑损伤(HIBD)中的作用和意义.方法 36只新生7日龄SD大鼠按照完全随机化方法分为对照组及HIBD 3h、6h、24h、48h、72h组,每组6只.观察HIBD后结扎侧大脑半球的大体形态变化,同时采用Real-time Q-PCR方法测定脑皮层组织MMP-9 mRNA和occludin mRNA的表达水平.结果 (1)新生大鼠HIBD后24~48 h结扎侧大脑半球脑水肿明显.(2)对照组大鼠MMP-9 mRNA表达水平极低(0.793 3±0.0859),在HIBD 3h组其表达开始增高(1.153 3±0.1291),24h达高峰(3.488 3±0.1759),72h仍维持较高的水平(1.6250±0.1157),与对照组比较,HIBD各时间点MMP-9 mRNA的表达均明显升高,差异有显著性(P<0.05).(3)对照组大鼠occludin mRNA表达水平较高(21780±0.0773),在HIBD 3h组其表达开始降低(1.718 6±0.1168),24h降至最低(0.9066±0.0602),72h仍维持较低水平(1.5966±0.0799),与对照组比较,HIBD各时间点occludin mRNA的表达均明显降低,差异有显著性(P<0.05);(4)缺氧缺血后各时间点MMP-9mRNA的表达与occludin mRNA的表达呈负相关(γ=-0.815,P<0.05).结论 脑缺氧缺血后MMP-9表达升高,TJ蛋白occludin表达减少,提示它们可能参与了HIBD的发病过程.  相似文献   

16.

Background

Restricted diffusion on diffusion-weighted imaging (DWI) sequences during magnetic resonance enterography (MRE) has been shown in segments of bowel affected by Crohn disease. However, the exact meaning of this finding, particularly within the pediatric Crohn disease population, is poorly understood.

Objective

The purpose of this study was to determine the significance of bowel wall restricted diffusion in children with small bowel Crohn disease by correlating apparent diffusion coefficient (ADC) values with other MRI markers of disease activity.

Materials and methods

A retrospective review of pediatric patients (≤ 18 years of age) with Crohn disease terminal ileitis who underwent MRE with DWI at our institution between May 1, 2009 and May 31, 2011 was undertaken. All of the children had either biopsy-proven Crohn disease terminal ileitis or clinically diagnosed Crohn disease, including terminal ileal involvement by imaging. The mean minimum ADC value within the wall of the terminal ileum was determined for each examination. ADC values were tested for correlation/association with other MRI findings to determine whether a relationship exists between bowel wall restricted diffusion and disease activity.

Results

Forty-six MRE examinations with DWI in children with terminal ileitis were identified (23 girls and 23 boys; mean age, 14.3 years). There was significant negative correlation or association between bowel wall minimum ADC value and established MRI markers of disease activity, including degree of bowel wall thickening (R?=?(?)0.43; P?=?0.003), striated pattern of arterial enhancement (P?=?0.01), degree of arterial enhancement (P?=?0.01), degree of delayed enhancement (P?=?0.045), amount of mesenteric inflammatory changes (P?<?0.0001) and presence of a stricture (P?=?0.02). ADC values were not significantly associated with bowel wall T2-weighted signal intensity, length of disease involvement or mesenteric fibrofatty proliferation.

Conclusion

Increasing bowel wall restricted diffusion (lower ADC values) is associated with multiple MRI findings that are traditionally associated with active inflammation in pediatric small bowel Crohn disease.  相似文献   

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