缓激肽B2受体在大鼠C6脑胶质瘤细胞上的表达

目的　研究缓激肽选择性开放脑肿瘤的血肿瘤屏障的机制。方法　通过双重免疫组化染色 ,确定缓激肽B2受体是存在于血管内皮细胞上还是存在于肿瘤细胞上。结果　在正常脑组织和肿瘤的血管内皮细胞上未见缓激肽B2受体的表达 ,而在肿瘤细胞上发现了高水平表达的缓激肽B2受体。结论　肿瘤细胞上B2受体的高水平表达可能是小剂量缓激肽灌注能够选择性开放恶性脑肿瘤的血 -肿瘤屏障而未影响正常血脑屏障通透性的重要原因之一。     

缓激肽对大鼠缺血区血脑屏障的影响

目的研究缓激肽对局部脑缺血区超微结构、血脑屏障的通透性及继发性脑水肿的影响。方法制备大鼠大脑中动脉缺血模型,在大脑中动脉缺血2hr再灌注1hr末,颈内动脉灌注小剂量缓激肽(10μg/kg/min),应用电镜观察血脑屏障超微结构的改变;测定脑组织伊文思蓝含量来判断血脑屏障的通透性;应用干湿法测定脑含水量的变化。结果缓激肽灌注大鼠脑毛细血管紧密连接开放,对照组大鼠紧密连接完整;与对照组相比,缓激肽灌注组缺血侧脑组织伊文思蓝含量明显高于缺血对照组(P<0.01),但再灌注24hr后脑含水量并没有增加(P>0.05)。结论小剂量缓激肽通过开放紧密连接来增加缺血区血脑屏障的通透性,但并不会增加继发性脑水肿的程度。     

缓激肽选择性增加局部脑缺血大鼠血脑屏障的通透性

目的　研究颈动脉灌注小剂量缓激肽对缺血后血脑屏障通透性的影响及机制。方法　免疫组化分析正常脑组织的缓激肽B2受体所在。大鼠大脑中动脉结扎 1h或 2h再灌流 1h。用放射自显影方法检测缓激肽对血脑屏障通透性的变化。WesternBlot方法检测bNOS ,iNOS和B2受体。NOS检测盒检测NOS的活性。结果　正常脑组织毛细血管内皮未见B2受体表达 ,在神经细胞上发现B2受体的表达。缺血 2h再灌流1h缓激肽灌注缺血区血脑屏障通透性显著增加。WesternBlot结果提示 ,在缓激肽灌注组和对照组间 ,缺血皮质区bNOS和B2受体没有明显变化 ,各组中均未检测出iNOS。缓激肽灌注组的NOS活性显著高于对照组。结论　正常脑组织毛细血管内皮未表达B2受体 ,神经细胞上可见B2受体的表达。灌注小剂量缓激肽能选择性增加局部脑缺血大鼠血脑屏障的通透性     

缓激肽受体抑制剂对脑缺血再灌注大鼠的脑保护作用

为了探讨缓激肽及其受体在脑缺血急性期对血脑屏障通透性及炎症因子分泌的影响,本研究采用线栓法制作大鼠大脑中动脉梗塞(MCAO)模型,分别应用缓激肽B1和B2受体的特异性抑制剂,在缺血再灌流后24h进行动物行为学评分,TTC染色计算梗死体积,伊文斯蓝染色检测血脑屏障通透性,透射电镜观测血脑屏障超微结构的变化,ELISA对缺血区IL-1β、TNF-α、PGE2进行测定。结果显示:缓激肽B1和B2受体抑制剂能够改善脑缺血大鼠急性期行为学评分、缩小梗死体积、降低血脑屏障通透性、维持血脑屏障结构完整、抑制炎症因子分泌,缓激肽B2受体抑制剂的上述效果优于B1受体抑制剂。以上结果提示缓激肽在脑缺血急性期可以加重脑损伤,其受体的特异性抑制剂可以减轻脑损伤。     

缓激肽对脑胶质瘤大鼠紧密连接影响的形态学观察

目的研究缓激肽(BK)对脑胶质瘤大鼠血肿瘤屏障紧密连接的影响。方法采用伊文氏兰(EB)法检测缓激肽作用后血肿瘤屏障(BTB)通透性的变化;应用透射电镜(TEM)观察BK作用后内皮细胞间紧密连接的变化,同时应用硝酸镧[La(NO3)3]和辣根过氧化物酶(HRP)作示踪剂,检测缓激肽作用后,小分子和大分子示踪剂通过紧密连接的情况。结果缓激肽可使血肿瘤屏障对伊文氏兰的通透性增加,在15min时达到高峰,以后逐渐下降。透射电镜显示缓激肽作用15min时,肿瘤组织毛细血管内皮细胞间紧密连接的完整性明显破坏,缝隙指数显著增加,同时可见硝酸镧和辣根过氧化物酶在紧密连接处沉积。结论缓激肽能够通过开放紧密连接选择性增加血肿瘤屏障的通透性。     

单纯疱疹病毒介导的白介素12对大鼠脑胶质瘤的基因治疗

目的　构建表达鼠白介素 12 (IL 12 )基因的重组单纯疱疹病毒 (HSV IL12 ) ,并测试对大鼠C6脑胶质瘤的实验治疗。方法　将IL 12的 p35和p4 0的两个亚单位基因分别插入单纯疱疹病毒的ICP34.5区 ,构建HSV IL12。结果　缓激肽开放血脑屏障的同时灌注HSV IL12显著地延长了动物的生存时间 ,有 4 0 %的动物生存期超过了 10个月。离体脾脏细胞CTL分析没有检测出T淋巴细胞溶解活性 ,而从肿瘤内收集的T淋巴细胞却有强烈的杀伤活性。结论　缓激肽开放血脑屏障的同时灌注HSV IL12可能是一个很有潜力的治疗脑胶质瘤的手段。     

聚焦超声联合微泡开放血脑屏障机制及监测方法的研究进展

聚焦超声联合微泡能够瞬时、局部和可逆地开放血脑屏障,该方法现已成为靶向投递药物治疗脑部疾病的一个研究热点。该文在详细介绍了血脑屏障的发现及其功能的基础上,介绍了聚焦超声联合微泡开放血脑屏障的可能机制,并分析对比了三种典型的血脑屏障开放监测方法(示踪剂法、医学影像学监测法和基于空化效应的监测法),最后对聚焦超声联合微泡开放血脑屏障的机制及其监测方法进行了展望。     

ATP敏感性钾通道蛋白在缓激肽选择性开放血肿瘤屏障中的表达

目的 探讨ATP敏感性钾通道蛋白在缓激肽选择性开放血肿瘤屏障中的作用.方法 建立大鼠脑胶质瘤模型, 颈内动脉灌注缓激肽后,采用免疫组化SABC法和 Western blot法测定肿瘤组织ATP敏感性钾通道蛋白的功能亚基Kir6.2的分布和表达的变化.结果 脑胶质瘤大鼠经颈内动脉灌注缓激肽后,其肿瘤内血管内皮细胞的 Kir6.2蛋白表达比对照组显著增多, 且以灌注后10 min 增加最为显著. 结论 ATP敏感性钾通道蛋白表达上调可能是缓激肽选择性开放血肿瘤屏障的重要机制之一.     

利用伊文思蓝的荧光显示肾上腺素诱发的血脑屏障开放

本文采用伊文思蓝静脉注射，在荧光显微镜下观察了不同剂量的肾上腺素诱发的大鼠血脑屏障开放状况，结果发现：（1）伊文思蓝在血脑屏障开放局部呈现出鲜艳明亮的荧光斑；（2）随着肾上腺素剂量加大，光斑数量增加；（3）光斑在实验组全脑的分布，以下丘脑、丘脑、小脑和尾壳核内密度最高。上述结果表明利用伊文思蓝的荧光染料性质观察血脑屏障的开放具有简便易行、灵敏度高等优越性．     

缓激肽持续作用对胶质瘤细胞内钙离子浓度的影响

目的探讨缓激肽持续作用引起的胶质瘤细胞内钙离子浓度变化([Ca2+]i)及机制。方法培养大鼠C6胶质瘤细胞,采用[Ca2+]i测定和免疫荧光细胞化学鉴定的方法,观察持续给予缓激肽后胶质瘤细胞内[Ca2+]i的变化和缓激肽B2受体在细胞内的分布。结果在第一次给予缓激肽时,引起[Ca2+]i的峰值最大,随着给予缓激肽次数的增加,缓激肽诱导的[Ca2+]i荧光强度峰值逐渐下降,在第5次加入缓激肽时,[Ca2+]i荧光强度峰值已无显著变化。在此过程中,缓激肽B2受体发生内化,并与胞浆中的质膜微囊蛋白caveolin-1结合。结论持续给予缓激肽可引起胶质瘤细胞内[Ca2+]i浓度规律变化,caveolin-1可能参与此过程。     

Bradykinin-induced blood-tumor barrier opening is mediated by tumor necrosis factor-alpha

Bradykinin has been shown to increase the permeability of blood-tumor barrier (BTB) selectively. This study was performed to determine whether tumor necrosis factor-alpha (TNF-alpha) was involved in the regulation of this biological process. We found that the levels of TNF-alpha mRNA and heat shock factor-1 (HSF1) protein in C6 cells were markedly up-regulated by bradykinin via real-time RT-PCR and Western blot methods. And the most obvious increase of HSF1 protein and TNF-alpha mRNA in C6 cells were observed at 5 min and 10 min of bradykinin perfusion, respectively. In addition, the radioactivity of TNF-alpha in C6 cells' culture fluid also mostly increased at 15 min of bradykinin perfusion. And the Evans blue content of brain tumor tissues in rats and the concentration of TNF-alpha reached the maximum at 15 min of bradykinin perfusion. Our results suggested that the bradykinin-mediated BTB permeability increase is due to accelerated release of TNF-alpha, which could cause the increase of BTB permeability by promoting to the release HSF1 from neurospongioma cells.     

The role of hyperemia in cellular hypersensitivity reactions

The three physiological processes vascular permeability, blood flow and lymphocyte migration were all enhanced in tuberculin reactions induced in guinea pigs and sheep and also in normal lymphocyte transfer reactions in sheep. Microspheres labelled with 85Sr were used to measure blood flow to dermal sites and it was found that cellular hypersensitivity reactions had blood flows 7-25 times that of normal skin at the reaction peak. Vascular permeability was measured as an increase in the flow rate of afferent lymph or, in guinea pigs, as the enhanced leakage of intravascular 125I-albumin. When the permeability-inducing peptide bradykinin was injected directly into tuberculin reaction, the resulting permeability was greater than the sum of the tuberculin and bradykinin permeability taken individually and it was concluded that the hyperemia enhanced the permeability-inducing capacity of bradykinin. When the traffic of lymphocytes through hypersensitivity lesions was measured in sheep by cannulating the regional afferent lymph vessels and continuously collecting the lymph, the increase in lymphocyte traffic was of the same order of magnitude as the increase in blood flow. It is suggested than the antigen-induced enhancement of blood flow caused the increase in lymphocyte traffic and that the mechanism was similar to that occurring within lymph nodes during the immune response to all antigens.     

大鼠脑微血管内皮细胞的原代培养及缓激肽的作用靶细胞探讨

目的建立稳定的原代大鼠脑微血管内皮细胞培养方法,并在体外探讨不同剂量缓激肽的作用靶细胞,进一步阐释缓激肽开放血脑和血肿瘤屏障的机理。方法运用免疫荧光测定原代培养的脑血管内皮细胞、星形胶质细胞及C6胶质瘤细胞在不同剂量缓激肽作用前后的细胞内钙离子变化,根据给药前后的荧光改变来确定不同剂量缓激肽的作用靶点细胞。结果小剂量缓激肽(终浓度:1μmol/L)可以引起C6胶质瘤细胞内的钙离子水平升高,而只有大剂量(终浓度:10μmol/L~1mmol/L)缓激肽才能触发星形胶质细胞内的钙离子水平升高,脑微血管内皮细胞对大、小剂量缓激肽均无任何反应。结论缓激肽的直接作用靶点是胶质细胞及C6胶质瘤细胞,缓激肽调节脑血管内皮细胞通透性的作用可能需要某些细胞间信使的参与。     

Bradykinin preconditioning induces protective effects on the spinal cord ischemic injury of rats

The study was performed to investigate the effects of bradykinin preconditioning on spinal cord ischemic injury using an in vivo transient spinal cord ischemia model in rats. Prior to ischemia, bradykinin was infused continuously via the left femoral artery starting 15min before ischemia. Neurological functions were evaluated for 7 days postoperatively using modified Tarlov's scores. Tarlov's score outcomes showed a marked improvement in the bradykinin group compared to the ischemia group. The blood-spinal cord barrier (BSCB) permeability was also decreased by bradykinin preconditioning after 72 h reperfusion focal spinal cord in rats, which was greatly reversed by B9430 (bradykinin B2 receptor antagonist). Immunohistochemical and Western blot analysis of spinal cords revealed a significant increase in basic fibroblast growth factor protein (bFGF) levels. The study demonstrated that bradykinin preconditioning induces protection against spinal cord ischemic injury, and this protection is likely due to the protection of the vasculature of the spinal cord and the promotion of neuronal survival.     

Capsaicin and blood-brain barrier permeability

The influence of perivascular sensory afferent nerve fibres upon the permeability of the blood-brain barrier was examined in halothane-anaesthetised rats. Blood-brain barrier permeability was assessed by the rate of transfer of the small neutral amino acid, [14C]alpha-aminoisobutyric acid, from blood to brain and by gross extravasation of Evans blue albumin. In every brain area examined, the acute administration of capsaicin (0.15-5 mumol/kg, i.v.) failed to alter significantly the passage into the brain of the small neutral amino acid tracer or to effect dye extravasation. Capsaicin, at concentrations which cause the release of vasoactive neuropeptides from nerve endings and increase vascular permeability in peripheral tissues, does not increase the permeability of the blood-brain barrier.     

Y-27632抑制缓激肽选择开放血肿瘤屏障的研究

目的研究Rho associated kinase（ROcK）特异性抑制剂Y-27632是否抑制缓激肽开放血肿瘤屏障。方法应用EVOM测定仪测定跨内皮阻抗值，分析血肿瘤屏障的通透性；应用辣根过氧化物酶渗漏实验分析血肿瘤屏障的通透性；应用免疫荧光方法观察原代大鼠脑微血管内皮细胞丝状肌动蛋白结构和分布的改变。结果BK作用15min时，跨内皮阻抗值最低，辣根过氧化物酶流量最高，血肿瘤屏障通透性最高；此时大鼠脑微血管内皮细胞边界的丝状肌动蛋白分布不连续，应力纤维形成增加。ROCK的特异性抑制剂Y-27632显著抑制了由缓激肽引起的血肿瘤屏障通透性升高和应力纤维的增加。结论Y-27632抑制缓激肽引起的血肿瘤屏障通透性升高，可能与丝状肌动蛋白结构和分布的改变和应力纤维的增加相关。