Effect of electromagnetic pulse exposure on permeability of blood-testicle barrier in mice

Objective To study the effect of electromagnetic pulse （EMP） exposure on the permeability of blood-testicle barrier （BTB） in mice. Methods Adult male BALB/c mice were exposed to EMP at 200 kV/m for 200 pulses with 2 seconds interval. The mice were injected with 2% Evans Blue solution through caudal vein at different time points after exposure, and the permeability of BTB was monitored using a fluorescence microscope. The testis sample for the transmission electron microscopy was prepared at 2 h after EMP exposure. The permeability of BTB in mice was observed by using Evans Blue tracer and lanthanum nitrate tracer. Results After exposure, cloudy Evans Blue was found in the testicle convoluted seminiferous tubule of mice. Lanthanum nitrate was observed not only between testicle spermatogonia near seminiferous tubule wall and sertoli cells, but also between sertoli cells and primary spermatocyte or secondary spermatocyte. In contrast, lanthanum nitrate in control group was only found in the testicle sertoli cells between seminiferous tubule and near seminifdrous tubule wall. Conclusion EMP exposure could increase the permeability of BTB in the mice.     

The effects of electromagnetic pulse on the protein levels of tight junction associated-proteins in the cerebral cortex, hippocampus, heart, lung, and testis of rats

Objective To investigate changes in the expression of tight junction (TJ) proteins in the cerebral cortex,hippocampus,heart,lung,and testes of rats after exposure to electromagnetic pulse (EMP).Methods Eighteen adult male Sprague-Dawley rats were divided into sham and exposure groups.The exposure groups received EMP at 200 kV/m for 200 pulses with a repetition rate of 1 Hz.The expression of TJ proteins (ZO-1,occludin,actin) in the several organs was examined by western blotting.Results ZO-1 levels in the ce...     

Detrimental Effect of Electromagnetic Pulse Exposure on Permeability of In Vitro Blood-brain-barrier Model

Objective To study the effect of electromagnetic pulse (EMP) exposure on permeability of in vitro blood-brain-barrier (BBB) model. Methods An in vitro BBB model, established by co-culturing brain microvascular endothelial cells (BMVEC) and astroglial cells (AC) isolated from rat brain, was exposed to EMP at 100 kV/m and 400 kV/m, respectively. Permeability of the model was assayed by measuring the transendothelial electrical resistance (TEER) and the horseradish peroxidase (HRP) transmission at different time points. Levels of BBB tight junction-related proteins were measured at 0, 1, 2, 4, 8, 12, 16, 20, 24 h after EMP exposure by Western blotting. Results The TEER level was lower in BBB model group than in control group at 12 h after EMP, exposure which returned to its normal level at 24 h. The 24 h recovery process was triphasic and biphasic respectively after EMP exposure at 100 kV/m and 400 kV/m. Following exposure to 400 kV/m EMP, the HRP permeability increased at 1-12 h and returned to its normal level at 24 h. Western blotting showed that the claudin-5 and ZO-1 protein levels were changed after EMP exposure. Conclusion EMP exposure at 100 kV/m and 400 kV/m can increase the permeability of in vitro BBB model and BBB tight junction-related proteins such as ZO-1 and claudin-5 may change EMP-induced BBB permeability.     

Effects of Electromagnetic Pulse on Bone Metabolism of Mice in vivo

Objective To study the effects of electromagnetic pulse （EMP） on bone metabolism of mice in vivo. Methods Twenty-four male BALB/c mice were divided into a control group and 2 experimental groups （n=8）. The whole-body of mice in experimental groups were exposed to 50 kV/m and 400kV/m EMP, 400 pulses daily for 7 consecutive days at 2 seconds intervals. Alkaline phosphotase （ALP） activity, serum calcium concentration and osteocalcin level and trabecular bone volume （BV/TV, %） were measured immediately after EMP exposure by biochemical, ELISA and morphological methods. Results The ALP activity, serum calcium concentration and osteocalcin level and BV/TV in experimental groups remained unchanged after EMP exposure. Conelusion Under our experimental conditions, EMP exposure cannot affect bone metabolism of mice in vivo.     

电磁脉冲对大鼠腺垂体结构和分泌功能的影响

目的 探讨电磁脉冲(EMP)对大鼠腺垂体结构和分泌功能的影响.方法 SD雄性大鼠48只,随机分为辐照组和假辐照组.辐照组大鼠接受200 kV/m EMP全身辐照,于辐照后12、24、48和96 h应用光镜、电镜观察腺垂体内分泌细胞形态学的改变,放射免疫法检测大鼠血清催乳素(PRL)、生长激素(GH)、促肾上腺皮质激素(ACTH)、促甲状腺激素(TSH)和黄体生成素(LH)的含量.结果 大鼠腺垂体超微结构在EMP辐照后12 h出现改变,至48 h逐渐加重,96 h有所恢复.主要病变为细胞水肿,线粒体肿胀、空泡化和髓鞘样结构形成,高尔基体和内质网扩张,次级溶酶体出现,细胞核内异染色质边集等.大鼠血清PRL和ACTH均表现为照后12 h显著升高后恢复;GH于照后12 h显著下降后逐渐回升,48 h恢复;TSH于12 h即开始下降,24 h显著下降至最低点,96 h恢复;LH于照后24～96h明显升高.结论 EMP辐照可引起大鼠腺垂体结构和分泌功能的改变.     

银杏叶提取物对模拟高原低氧暴露下大鼠血脑屏障的保护作用

目的观察银杏叶提取物（GBE）对模拟高原低氧暴露下大鼠血脑屏障的保护作用,并初步阐明其机制。方法将48只SD大鼠随机分为4组,低压舱模拟海拔高度7000m连续减压缺氧3d制备大鼠实验性高原脑水肿模型。GBE前期干预组在缺氧前3d按60mg/（kg.d）给予GBE干预处理,GBE后期干预组在缺氧开始24h后按相同剂量给予GBE至减压缺氧结束,以湿干比值法评价其对脑含水量的影响,硝酸镧示踪法观察GBE对低氧暴露下血脑屏障通透性的影响。结果 GBE前期干预组和GBE后期干预组大鼠脑含水量和硝酸镧颗粒渗出均明显少于高原对照组（P〈0.01）,且GBE前期干预组的效果显著优于GBE后期干预组（P〈0.01）。结论 GBE对低氧暴露下血脑屏障通透性增高具有一定保护作用。     

高原反应的脑病理与水通道蛋白-4(AQP4)的相关性实验研究

目的研究高原反应的脑病理变化及发病机制.方法Wistar大白鼠56只,分正常对照和实验组,实验组进入模拟5 000 m高原环境饲养,取4、24、48 h、3 d、2、4周各组各时相点动物活杀取脑作光、电镜一般形态学观察,硝酸镧示踪血管通透性观察,水通道蛋白(AQP4)和mRNA光、电镜免疫组化和原位杂交,GLU(glutamate,谷氨酸),GABA(gamm-aminobutyric,γ氨基丁酸)含量检测.结果光、电镜观察显示实验组早期(4～72 h)脑毛细血管内皮细胞出现吞饮泡增多、线粒体肿胀、紧密连接松弛、胶质足肿胀以及(24、48 h)硝酸镧漏出血管腔等病理改变,神经细胞无明显病理变化;免疫组化和原位杂交显示AQP4在血管内皮细胞、胶质纤维阳性表达,AQP4 mRNA在毛细血管内皮细胞核和胶质细胞核呈阳性表达,二者的表达情况在实验组早期增高.结论BBB病变是动物进入高原出现较早的病理变化;早期胶质细胞肿胀可能是一种保护性调节;AQP4 mRNA的表达变化可能是调节BBB通透性并维持水平衡的分子机制.     

Gene expression changes in the pituitary gland of rats exposed to electromagnetic pulses

Objective We examined alterations in the expression of tumorigenesis‐related genes in the pituitary gland of rats exposed to electromagnetic pulses (EMP).Methods The global gene expression profiles of the pituitary gland in EMP‐exposed and control groups were detected by cDNA microarray analysis.We then validated and further investigated the reduced expression of two tumorigenesis‐related genes,Pten,and Jund,by assessing their mRNA and protein expression by quantitative real‐time‐PCR,western blotting,and im...     

伽玛刀照射正常大鼠后急性期血脑屏障通透性的改变

目的：观察伽玛刀照射正常大鼠后急性期血脑屏障（blood-brain barrier,BBB)通透性的改变。方法：选择正常大鼠右侧尾状核头部为照射靶点，动物按伽玛刀最大照射剂量分为20、50、75、160Gy4组，准直器直径为4mm。于伽玛刀照射后12h至14d内应用兔多抗清蛋白行免疫组化染色半定量分析；并以硝酸镧作为示踪剂，应用透射电镜观察BBB的超微结构改变。结果：免疫组化法显示160Gy和75Gy剂量组于照射后12h，50Gy和20Gy剂量组于照射后1d靶区内出现血浆蛋白外渗；硝酸镧示踪电镜显示160Gy、75Gy和50Gy组于照射后12h、20Gy组于照射后1dBBB内皮细胞间的紧密连接开放。75Gy、50Gy、20Gy组变化高峰期出现在照射后3d，而7d后开始消散，160Gy组靶区阳性反应持续至照射后14d。结论：大鼠在伽玛刀照射后急性期存在BBB通透性改变，这种改变在20－75Gy范围内具有自限性。     

驻极体对烫伤大鼠肺血管壁通透性变化的影响

通过检测肺组织匀浆中荧光标记白蛋白的含量，观察了大鼠烫伤６，１２，２４ｈ后肺血管壁通透性的变化及－１００、－２５０，－５００，－７５０，－１０００Ｖ驻极体对这种变化的影响。     

急性低压缺氧暴露后血脑屏障通透性的变化及其意义

目的：观察在急性低压缺氧条件下,大鼠血脑屏障通秀性的变化特点,为阐明低压缺氧作用下脑功能障碍的可能机理及临床上特殊病例治疗方案的确定提供生理学依据。方法：选择在雄性SD大鼠12只,随机分为对照组、5000m急性低压缺氧暴露组。实验组动物于低压舱内,以20m/s的速率上升,至5000m,停留5hm,而后以20m/s的速率下降至地面;出舱后立即经心脏灌注硝酸镧固定液,开颅取脑,制成切片,置透射电镜下观察。结果：急性低压缺氧暴露5h后即刻,即可见镧颗粒通过大鼠脑皮质的毛细血管内皮细胞膜,沉积于毛细血管内皮细胞浆内、细胞核膜上以及血管周围,弥漫性地分布于脑间质细胞间隙,并附着于神经细胞膜上,而对照组大鼠,镧颗粒仅滞留于大脑皮层的毛细血管腔内。结论：5000m以上低压缺氧连续暴露5h,可引起大鼠血脑屏障通透性增加。这可能在低压缺氧导致脑水肿的发生以及脑功能障碍的过程中起重要作用,对确定临床上特殊病例的治疗也有一定参考价值。     

工频高压电场对动物血清中几种元素的影响

大鼠和家兔暴露于50Hz、40kV/m电场中100～500小时,血清钠,钾、钙和镁无明显变化;而血清锌暴露200小时则显著降低,血清铜暴露300、400和500小时显著增高,铜/锌比值在200、300、400和500小时显著增高。结果提示血清铜/锌比值是反映工频电场对机体作用的敏感指标。     

电磁脉冲对海马N-甲基-D-天冬氨酸受体蛋白表达水平的影响

目的:研究电磁脉冲(electromagnetic pulse,EMP)对海马组织中N-甲基-D-天冬氨酸受体(Nmethyl-D-aspartate receptor,NMDAR)蛋白表达的影响.方法:采用Western blotting蛋白印迹法,对EMP照射前后海马组织中NMDAR的蛋白表达进行检测.结果:EMP照后1h NMDAR蛋白表达升高,持续至24h达最高点(与对照组相比,P＜0.05),之后回降.结论:在电磁脉冲照射后早期,中枢神经系统内存在有效的代偿机制,合成新的受体分子以适应功能的需要.     

用硝酸镧示踪法观察渗透性血脑屏障开放后的超微结构变化

用兔颈内动脉注入1.4M甘露醇法、制作了渗透性血脑屏障开放的模型。选硝酸镧作示踪剂,用血管灌注法和块染法对血脑屏障开放后的超微结构变化进行了观察。电镜检查表明镧可由血管内通过内皮细胞间的紧密连接,达内皮下层和细胞外间隙,或从血管外进入血管内。实验提示:渗透性血脑屏障开放的形态学基础是血管内皮细胞间的紧密连接开闭的可逆性改变。镧血管灌注法的示踪效果优于镧的块染法。     

清热化痰解毒汤对缺血性脑卒中大鼠脑组织含水量、血-脑脊液屏障通透性及神经功能缺损评分的影响

目的 探讨清热化痰解毒汤对实验性缺血性脑卒中大鼠脑组织含水量、血-脑脊液屏障通透性及神经功能缺损评分影响。方法 采取单侧颈动脉结扎制作SD大鼠模型,分为假手术组、缺血模型组、中药治疗组(即清热化痰解毒汤)、尼莫地平组,采用干湿法测脑组织含水量、Garcia神经功能评分及伊文思兰示踪剂测出其漏出量。结果 与假手术组(36.20±1.24)%比较,缺血模型组在缺血24 h脑组织的含水量开始有所缓慢增加,但与中药治疗组、尼莫地平组比较差异无统计学意义,而到缺血72 h时缺血模型组大鼠脑组织含水量(54.40±2.16)%则明显增加,与24 h时比较差异有统计学意义(P<0.05);中药治疗组在应用清热化痰解毒汤后其实验大鼠脑组织含水量明显减少,其中在缺血72 h时间点的脑组织含水量(42.30±1.12)%与缺血模型组比较差异有统计学意义(P<0.01);同时尼莫地平组在缺血72 h的时间点上实验大鼠脑组织的含水量(43.20±1.23)%亦较之缺血模型组明显减少,差异有统计学意义(P<0.01)。同时通过神经功能评分及伊文思兰示踪剂,发现72 h后中药治疗组及尼莫地平均与假手术组比较有统计学意义(P<0.01),神经功能缺损评分增加而血-脑脊液屏障通透性下降。结论 清热化痰解毒汤对急性缺血性脑卒中大鼠脑组织有保护作用。     

镧盐块染技术在急性脑缺血与再灌流模型中的应用

在急性脑缺血与再灌流动物模型中采用硝酸镧块染法对神经细胞膜的通透性改变示踪。电镜下发现正常组织镧盐不能进入细胞内;而缺血和缺血后再灌流组细胞膜受损,镧离子即可在线粒体外膜又能在线粒体内嵴处沉积。该方法示踪神经细胞膜通透性改变简便易行,效果较好。     

补铁对生长发育期铅接触大鼠血脑屏障通透性的影响

目的: 探讨补铁对生长发育期慢性铅接触大鼠血脑屏障(blood-brain barrier,BBB)通透性及内皮细胞紧密连接蛋白的影响.方法: 选择 21 d龄的雄性SD大鼠38只,随机分为对照组(n=10)、染铅组(n=14)和补铁且染铅组(n=14).除对照组外,其他两组均自由饮用含400 mg/L的Pb(AC)2水溶液;补铁且染铅组以20 mg/kg浓度的FeSO4水溶液隔日进行ig,其他两组以相同的方法隔日用去离子水ig.饲养6 wk后,检测大鼠的血红蛋白和血铅含量,用硝酸镧示踪法观察血脑屏障的通透性,并测定脑组织内皮细胞紧密连接蛋白occludin的表达.结果: 补铁且染铅组与染铅组相比,大鼠的血红蛋白含量显著增高(P<0.05),血铅含量显著降低(P<0.05);电镜下观察可见,染铅组大鼠毛细血管内的镧盐颗粒穿过血脑屏障进入到脑组织内,而补铁且染铅组与对照组均未见镧盐颗粒渗透过血脑屏障.同时,补铁且染铅组内皮细胞紧密连接蛋白occludin的表达水平与染铅组相比明显增加.结论: 生长发育期铅接触可使血脑屏障通透性增加,脑毛细血管内皮细胞紧密连接蛋白occludin表达降低可能是血脑屏障通透性改变的主要分子机制之一;铅接触的同时适量补充铁元素,可保护由慢性铅接触所造成的血脑屏障紧密连接的损伤.     

Ⅱ.微波对大鼠血睾屏障影响的电镜观察

作者用微波照射大鼠睾丸后,以硝酸镧作示踪剂,于照后1天、7天、14天和70天,用电镜观察20只大鼠血睾屏障的变化。结果发现,血屏睾障的结构和对硝酸镧的通透性均未见异常。     

An Ultrastructural Study on Hyperosmotic Opening of Tight Junction by Lanthanum Nitrate Tracing

A model of hyperosmotic opening of the blood-brain barrier(BBB)was successfully made by infusion of 1.4M mannitol into the internal carotidartery of rabbit.We selected lanthanum nitrate as a tracer.Ultrastructuralchanges of hyperosmotie opening of the BBB were observed through injection oflanthanum nitrate into blood vessels or through impregnation of small blocks ofbrain tissue in lanthanum solution.Electron microscopy showed that lanthanumnitrate passed through the opening of endothelial tight junction from the bloodinto the subendothelial layers and the extracellular spaces of the brain,or fromthe outside into the inside of blood vessels.The data suggest that themorphological basis of osmotic opening of BBB is the reversible widening of thetight junctions between endothelial cells,and that lanthanum nitrate infusion hasan advantage over block impregnation.     

siRNA沉默脑组织血管内皮生长因子表达对高原大鼠血脑屏障通透性的影响

目的 观察siRNA沉默脑组织血管内皮生长因子(VEGF)表达后对高原大鼠血脑屏障通透性的影响,探讨高原脑水肿的病理机制和预防方法.方法 50只Wistar大鼠随机分入正常对照组(NC)、高原对照组(HC)、脑室生理盐水对照组(SC)、siRNA静脉干预组(IVI)和siRNA脑室干预组(CVI).建立高原大鼠模型;NC组大鼠正常饲养;HC组大鼠造模前给予尾静脉内注射生理盐水;SC组在造模前给予脑室注射生理盐水;IVI组在造模前给予尾静脉注射VEGF特异性siRNA,CVI组给予脑室内注射VEGF特异性siRNA.造模24 h后迅速断头取前脑,干湿重法测定脑组织含水百分率及应用荧光素钠透过率测定血脑屏障通透性;实时荧光定量RT-PCR检测VEGF-mRNA表达,Western印迹法测定大鼠脑组织VEGF表达.结果 HC组脑组织VEGF-mRNA、VEGF表达及NaFl含量均显著高于NC组[VEGF-mRNA从(21.6±3.5)Kcopies/μg上升到(36.3 ±3.9)Kcopies/μg,VEGF从0.48±0.09增加到0.77±0.12,NaFl含量从(548±48)rfu/mg增加到(674±32)rfu/mg,均P＜0.01].与HC组相比,IVI组脑组织VEGF mRNA、VEGF表达及NaFl含量差异无统计学意义(均P＞0.05).CVI组腩组织VEGF-mRNA、VEGF表达及NaFl显著低于HC组[VEGF-mRNA从(36.3±3.9)Kcopies/μg降低到(19.9 ±4.3)Kcopies/μg,P＜0.01;VEGF从0.77±0.12降低到0.44 ±0.13,P＜0.01;NaFl含量从(674±32)rfu/mg下降到(542±77)rfu/mg,P＜0.05].各组间脑组织含水率差异无统计学意义(P＞0.05).结论 高原低氧诱发的VEGF表达增高是高原脑水肿的重要病理环节,脑室内应用特异性沉默VEGF的siRNA可阻断VEGF的表达,抑制毛细血管通透性增高,可成为预防高原脑水肿的新途径.