Local Delivery of Nimodipine by Prolonged-Release Microparticles—Feasibility,Effectiveness and Dose-Finding in Experimental Subarachnoid Hemorrhage

Background and Purpose

To investigate the effect of locally applied nimodipine prolonged-release microparticles on angiographic vasospasm and secondary brain injury after experimental subarachnoid hemorrhage (SAH).

Methods

70 male Wistar rats were categorized into three groups: 1) sham operated animals (control), 2) animals with SAH only (control) and the 3) treatment group. SAH was induced using the double hemorrhage model. The treatment group received different concentrations (20%, 30% or 40%) of nimodipine microparticles. Angiographic vasospasm was assessed 5 days later using digital subtraction angiography (DSA). Histological analysis of frozen sections was performed using H&E-staining as well as Iba1 and MAP2 immunohistochemistry.

Results

DSA images were sufficient for assessment in 42 animals. Severe angiographic vasospasm was present in group 2 (SAH only), as compared to the sham operated group (p<0.001). Only animals within group 3 and the highest nimodipine microparticles concentration (40%) as well as group 1 (sham) demonstrated the largest intracranial artery diameters. Variation in vessel calibers, however, did not result in differences in Iba-1 or MAP2 expression, i.e. in histological findings for secondary brain injury.

Conclusions

Local delivery of high-dose nimodipine prolonged-release microparticles at high concentration resulted in significant reduction in angiographic vasospasm after experimental SAH and with no histological signs for matrix toxicity.     

A calcium channel blocker flunarizine attenuates the neurotoxic effects of iron

Iron is a metal highly concentrated in liver and brain tissue, and known to induce neuronal hyperactivity and oxidative stress. It has been established that iron levels rise in the brain in some neurodegenerative diseases such as Parkinson's and Alzheimer's diseases (AD). A body of evidence indicates a link between neuronal death and intracellular excessive calcium accumulation. The aim of the present study was to investigate the effects of a calcium antagonist, flunarizine, on neurotoxicity induced by intracerebroventricular (i.c.v.) iron injection. For this reason rats were divided into three groups as control, iron and iron+flunarizine groups. Animals in iron and iron+flunarizine groups received i.c.v. FeCl₃ injection (200 mM, 2.5 μl), while control rats received the same amount of saline into the cerebral ventricles. Rats in iron+flunarizine group also received i.c.v. flunarizine (1 μM, 2 μl) following FeCl₃ injection. All animals were kept alive for ten days following the operation and animals in iron+flunarizine group received intraperitoneal (i.p.) flunarizine injections once a day (10 mg/kg/day) during this period. After ten days, rats were sacrificed. The total numbers of neurons in hippocampus of all rats were estimated with the latest, unbiased stereological techniques. Findings of the present study suggest that flunarizine may attenuate the neurotoxic effects of iron injection by inhibiting the cellular influx of excessive calcium ions.     

烟酰胺经调控p38MAPK信号通路对高血压脑出血大鼠的脑保护作用机制分析

摘要 目的：探讨烟酰胺经调控p38MAPK信号通路对高血压脑出血大鼠的脑保护作用机制。方法：选择48只SD大鼠,随机选择12只作为假手术组,其余36只进行高血压脑出血造模,对比4组大鼠的血肿体积、左扭转比率、神经功能变化、出血脑组织p-p38MAPK、p38MAPK蛋白表达、烟酰胺腺嘌呤二核苷酸、凋亡诱导因子含量及脑组织含水量。结果：与模型组相比,尼莫地平组、烟酰胺组的血肿体积明显缩小;与烟酰胺组相比,尼莫地平组的血肿体积明显缩小（P<0.05）;与干预前相比,干预后烟酰胺组、尼莫地平组的血肿体积明显缩小,模型组的血肿体积明显增多（P<0.05）。与模型组相比,假手术组、尼莫地平组、烟酰胺组的向左扭转比率、p-p38MAPK/p38MAPK、烟酰胺腺嘌呤二核苷酸明显较高,脑组织含水量、凋亡诱导因子含量明显较低;与烟酰胺组相比,尼莫地平组、假手术组的左扭转比率、p-p38MAPK/p38MAPK、烟酰胺腺嘌呤二核苷酸明显较高,脑组织含水量、凋亡诱导因子含量明显较低;与尼莫地平组相比,假手术组的左扭转比率、p-p38MAPK/p38MAPK、烟酰胺腺嘌呤二核苷酸明显较高,脑组织含水量、凋亡诱导因子含量明显较低（P<0.05）。结论：在高血压脑出血大鼠中,p38MAPK介导的细胞凋亡途径会加剧高血压脑出血的脑损伤,烟酰胺会经过抑制p38MAPK信号通路减轻高血压脑出血后的脑损伤。     

大鼠脑血管痉挛时NO和ET—1变化及尼莫地平的影响

目的探讨蛛网膜下腔出血(SAH)后脑血管痉挛(CVS)时脑组织一氧化氮(NO)和内皮素-1(ET-1)含量变化及尼莫地平(ND)对其影响。方法将135只Wistar大鼠随机均分为SAH组、ND处理组和假手术组,观察手术前后基底动脉管径,及24h内局部脑血流量(rCBF)、脑组织NO和ET-1含量动态改变,并行海马病理检查。结果SAH后rCBF明显而持续降低,基底动脉管径显著缩小;海马CAl区锥体细胞严重受损;脑组织NO和ET-1含量均在SAH后1～24h显著增加(P＜0．05～0．01)。ND处理后使上述异常变化均减轻。结论SAH后脑组织NO、ET-1增多可能参与了CVS所致脑损害过程,ND通过减轻CVS和拮抗脑组织NO及ET-1的病理性改变而发挥脑保护作用。     

A Low Mortality Rat Model to Assess Delayed Cerebral Vasospasm After Experimental Subarachnoid Hemorrhage

Objective: To characterize and establish a reproducible model that demonstrates delayed cerebral vasospasm after aneurysmal subarachnoid hemorrhage (SAH) in rats, in order to identify the initiating events, pathophysiological changes and potential targets for treatment.Methods: Twenty-eight male Sprague-Dawley rats (250 - 300 g) were arbitrarily assigned to one of two groups - SAH or saline control. Rat subarachnoid hemorrhage in the SAH group (n=15) was induced by double injection of autologous blood, 48 hr apart, into the cisterna magna. Similarly, normal saline (n=13) was injected into the cisterna magna of the saline control group. Rats were sacrificed on day five after the second blood injection and the brains were preserved for histological analysis. The degree of vasospasm was measured using sections of the basilar artery, by measuring the internal luminal cross sectional area using NIH Image-J software. The significance was tested using Tukey/Kramer''s statistical analysis.Results: After analysis of histological sections, basilar artery luminal cross sectional area were smaller in the SAH than in the saline group, consistent with cerebral vasospasm in the former group. In the SAH group, basilar artery internal area (.056 μm ± 3) were significantly smaller from vasospasm five days after the second blood injection (seven days after the initial blood injection), compared to the saline control group with internal area (.069 ± 3; p=0.004). There were no mortalities from cerebral vasospasm.Conclusion: The rat double SAH model induces a mild, survivable, basilar artery vasospasm that can be used to study the pathophysiological mechanisms of cerebral vasospasm in a small animal model. A low and acceptable mortality rate is a significant criterion to be satisfied for an ideal SAH animal model so that the mechanisms of vasospasm can be elucidated ^{7, 8}. Further modifications of the model can be made to adjust for increased severity of vasospasm and neurological exams.     

Pre-electroconvulsive shock administration of calcium channel blockers reduces retrograde amnesia induced by ECS

Effect of pre-electroconvulsive shock (ECS) administration of calcium channel blockers (CCBs) like verapamil, diltiazem, nifedipine, nimodipine, flunarizine and cinnarizine on retrograde amnesia induced by ECS was examined using passive avoidance paradigm in rats. The groups (Gr 1-7) of adult, male Wistar rats received true ECS with CCBs (5mg/kg; i.p) or vehicle (10 ml/kg; ip) and other groups (Gr 8-14) received sham ECS with CCBs (5mg/kg; i.p) or vehicle (10 ml/kg; i.p). The anti-amnestic activity of CCBs were evaluated using the passive avoidance paradigm in rats. Results showed that, the baseline latencies for all the groups did not differ significantly. Rats receiving true ECS produced significantly lower latencies. There was increase in the post ECS step through latencies of the rats administered CCBs before ECS. Therefore, pre-ECS administration of calcium channel blockers might reduce retrograde amnesia produced by ECS without altering seizure duration.     

Reversal of delayed vasospasm by an inhibitor of the synthesis of 20-HETE

This study characterized the time course of changes in cerebral blood flow (CBF) and vascular diameter in a dual-hemorrhage model of subarachnoid hemorrhage (SAH) in rats and examined whether acute blockade of the synthesis of 20-hydroxyeicosatetraenoic acid (20-HETE) with N-(3-chloro-4-morpholin-4-yl)phenyl-N'-hydroxyimido formamide (TS-011) can reverse delayed vasospasm in this model. Rats received an intracisternal injection of blood (0.4 ml) on day 0 and a second injection 2 days later. CBF was sequentially measured using laser-Doppler flowmetry, and the diameters of the cerebral arteries were determined after filling the cerebral vasculature with a casting compound. CBF fell to 67% of control after the first intracisternal injection of blood but returned to a value near control 24 h later. CBF again fell to 63% of control after a second intracisternal injection of blood and remained 30% below control for 5 days. The fall in CBF after the second intracisternal injection of blood was associated with a sustained 30% reduction in the diameters of the middle cerebral, posterior communicating, and basilar arteries. Acute blockade of the synthesis of 20-HETE with TS-011 (0.1 mg/kg i.v.), 5 days after the second SAH, increased the diameters of the cerebral arteries, and CBF returned to control. These results indicate that the rats develop delayed vasospasm after induction of the dual-hemorrhage model of SAH and that blockade of the synthesis of 20-HETE fully reverses cerebral vasospasm in this model. They also implicate 20-HETE in the development and maintenance of delayed cerebral vasospasm.     

盐酸戊乙奎醚（长托宁）抑制脑缺血／再灌注时谷氨酸的释放及受体机制研究

目的：观察盐酸戊乙奎醚对全脑缺血／再灌注大鼠易损区海马谷氨酸（Glu）及其受体（NMDAR1）的影响,探讨盐酸戊乙奎醚脑保护作用机制。方法：雄性Wistar大鼠60只,随机分为3组（n=20）：假手术组（A组）;缺血再灌注对照组（B组）;盐酸戊乙奎醚干预组,采用Pulsinelli-Brierley四血管阻断法制备全脑缺血模型,实验分两部分进行,各组随机选择10只大鼠于全脑缺血15min再灌注1h、3h、6h,采用脑微透析技术结合高效液相色谱（HPLC）检测大鼠海马细胞外Glu水平的变化,其余10只大鼠于再灌注3h后灌流固定断头取脑,采用免疫组织化学方法,检测海马CA1区NMDAR1蛋白表达。结果：与缺血／再灌注组各对应时点相比较,盐酸戊乙奎醚干预组大鼠海马细胞外Glu含量明显降低,统计结果差异均有显著性（P〈0．05或P〈0．01）;海马CA1区NMDAR1表达明显受抑制,积分光密度、阳性细胞面积、平均灰度值均存在显著性差异（P〈0．05或P〈0．01）。结论：脑缺血／再灌注早期应用盐酸戊乙奎醚不仅减少兴奋性氨基酸释放,还能抑制NMDAR1的高表达而产生脑保护作用。     

仙灵骨葆对骨质疏松大鼠OPG/RANK/RANKL 表达的影响

目的:观察仙灵骨葆治疗骨质疏松模型大鼠后,对大鼠体内OPG/RANKL/RANK表达的影响。方法:卵巢摘除法建立SD大鼠骨质疏松模型,设立假手术组、对照组(单纯去卵巢组)、雌激素组(给予17β-雌二醇)和治疗组(给予仙灵骨葆)。术后1周开始给药,给药12周后检测各组大鼠股骨骨密度,ELISA法检测血清中OPG/RANKL含量,RT-PCR检测骨组织中OPG/RANK/RAN-KL mRNA表达,免疫组化检测骨组织中RANK的表达。结果:对照组大鼠骨密度显著低于假手术组;治疗组和雌激素组大鼠O-PG表达显著高于对照组,RANK及RANKL的表达显著低于对照组。结论:采用卵巢摘除法成功建立大鼠骨质疏松模型;仙灵骨葆可促进骨质疏松大鼠OPG的表达,并抑制RANK及RANKL的表达,对骨质疏松模型大鼠有治疗作用。     

Chuanxiongzine-astragaloside IV decreases IL-1β and Caspase-3 gene expressions in rat brain damaged by cerebral ischemia/reperfusion: a study of real-time quantitative PCR assay

The purpose of this study was to establish an absolute quantitative method to detect IL-1β and Caspase-3 gene expressions in rat brain after cerebral ischemia-reperfusion (I/R) using real-time PCR. Rats were randomized into the following groups: sham operation group, model group (cerebral I/R group), astragaloside IV (AST IV) group, chuanxiongzine-AST IV group and nimodipine group (n = 10 in each group). The rats in all the groups except sham operation group were subjected to cerebral I/R treatment. Sham operation and model groups were treated by normal saline (5 mL/kg). AST IV, chuanxiongzine-AST IV and nimodipine groups received 20 mg/kg AST IV, 10 mg/kg chuanxiongzine plus 20 mg/kg AST IV, and 10 mg/kg nimodipine treatments, respectively. The administrations of drugs were performed with intraperitoneal injections at 0 and 12 h, 1 d, 2 d, 3 d, till to 7 d after I/R. A real-time quantitative PCR assay was developed for absolute quantification of the expressions of IL-1β and Caspase-3 genes. The absolute quantification approach relies on the construction of an accurate standard curve. Thus, two plasmids which contained rat IL-1β and Caspase-3 genes respectively were constructed. The cloned circular plasmids were then quantified using a spectrophotometer and used as standards. Standard curves were generated, and the copy numbers of IL-1β and Caspase-3 mRNA isolated from I/R-damaged brain tissue were also calculated by SYBR Green I dye method using specific primers. The results showed that melting curves exhibited sharp peaks, and PCR product also generated prominent band with expected size in agarose gel electrophoresis, which validated the optimization of the selected primer sets of IL-1β and Caspase-3 genes. The optimal annealing temperatures of IL-1β and Caspase-3 genes were 59 °C and 61.2 °C, respectively. Real-time PCR results showed that the expression of IL-1β and Caspase-3 genes in the model group was significantly elevated compared to that in the sham operation group. However, compared to those in the model group, IL-1β and Caspase-3 gene expressions were obviously decreased in AST IV, chuanxiongzine-AST IV and nimodipine groups. Especially in chuanxiongzine-AST IV group, those two genes showed the most significant expression down-regulation. These results suggest the absolute quantitative method established in the present study is capable of detecting the changes of IL-1β and Caspase-3 gene expressions in rat brain damaged by I/R.     

HCN2在大鼠外周神经病理性疼痛发生中的作用

目的：初步探讨超极化激活的环核苷酸门控通道2型（HCN2）在外周神经病理性疼痛发生中的作用。方法：将24只健康成年大鼠进行随机分组（n=12）：假手术组（Sham）大鼠仅分离左侧L4、L5脊神经,模型组（SNL）分离脊神经后进行相应的结扎处理,手术7 d后用行为学方法进行模型评价;将造模成功的大鼠进行随机分组（n=6）：①阴性对照组（Saline）,左侧足底注射生理盐水;②阳性对照组（GBPT）,腹腔注射加巴喷丁;③实验组（ZD7288）,左侧足底注射HCN非特异性阻断剂ZD7288。在给药前以及给药后1 h、4 h、24 h、48 h用疼痛行为学实验检测其对神经病理性疼痛的作用;分别取手术前对照组（Control）、假手术组（Sham）和模型组（SNL）大鼠的背根神经节（DRG）（n=6）,利用qPCR和Western blot的方法研究造模前后大鼠DRG内HCN2的表达的变化情况。结果：①成功建立大鼠神经痛模型;②与Saline组比较,GBPT组和ZD7288组在注射1 h后,均能明显的减轻大鼠神经病理性疼痛的症状（P<0.01）,而GBPT组和ZD7288组之间比较则无差异;③与Control组和Sham组相比较,SNL组大鼠DRG内的HCN2 mRNA表达量明显增加（P<0.01）;与Control组和Sham组相比较,SNL组大鼠DRG内的HCN2通道蛋白表达量显著增加（P<0.05）。结论：HCN2参与外周神经病理性疼痛的发生,并有可能成为治疗神经病理性疼痛一个潜在的新靶点。     

醒脑静对颅脑创伤的保护作用

目的：探讨醒脑静对颅脑损伤大鼠的保护作用及其机制。方法：健康雄性成年SD大鼠63只,随机分为3组（n=21）：假手术组、模型组、醒脑静组。模型组与醒脑静组均采用自由落体撞击伤方法制作创伤性脑损伤模型,假手术组仅行开颅术,不造成脑损伤。醒脑静组盆大鼠造模后10min内经尾静脉注射醒脑静注射液10ml／（kg·d）,模型组与假手术组则经尾静脉注射等量0．9％氯化钠溶液,三组均连续给药7d。给药第7天比较各组大鼠血清中S-100B蛋白和神经特异性烯醇化酶（NSE）水平,脑组织含水量,检测血清中超氧化物歧化酶（SOD）、丙二醛（MDA）和谷胱甘肽过氧化物酶（GSH—Px）含量,并对各组大鼠进行神经功能缺损评分。结果：与假手术组比较,醒脑静组和模型组均有明显的神经缺损,脑组织含水量、MDA、S-100B蛋白和NSE水平明显升高,SOD、GSH-Px含量明显降低;醒脑静组与模型组比较,醒脑静组神经缺损程度及脑含水量显著低于模型组,血清中MDA和NSE水平明显低于模型组,SOD、GSH-Px活性明显高于模型组。结论：醒脑静注射液对大鼠颅脑损伤具有保护作用,其作用机制可能与减轻颅脑损伤后脑水肿及抑制氧自由基反应、保护神经细胞有关。     

瑞舒伐他汀预处理对心肌缺血再灌注损伤大鼠自噬和凋亡的影响及机制研究

目的:探讨瑞舒伐他汀预处理对心肌缺血再灌注损伤(MIRI)大鼠自噬因子和凋亡相关基因的影响及作用机制.方法:将60只SD级大鼠纳入研究,遵循随机数字表法分成假手术组、模型组以及预处理组,每组20只.模型组以及预处理组大鼠均制备MIRI模型,假手术组按照相同的方式开胸,仅穿线不进行冠状动脉的结扎.模型制备前7d,预处理组...     

低氧诱导因子在肾炎大鼠肾小管间质中的表达及氯沙坦的保护作用研究

目的：观察低氧诱导因子在肾炎大鼠肾小管间质中表达的变化以及氯沙坦对肾炎的保护作用。方法：雄性Wistar 大鼠32只,随机分成假手术组、肾炎模型组、氯沙坦小剂量组、氯沙坦大剂量组各8 只,假手术组不做肾脏切除,其他组在右肾切除后尾静脉注射标记抗体。给药组则按量分别灌胃给药,8 周时处死。结果：大剂量给药组的血肌酐（Scr）、收缩压和24 h尿蛋白量较模型组显著降低,且小剂量给药组的血肌酐（Scr）和24h 尿蛋白量较模型组也显著降低。小剂量组和大剂量组大鼠的肾间质面积较肾炎模型组均显著降低。HIF-1αmRNA 大量表达于肾小管上皮细胞胞质和间质细胞胞质,且与模型组比较,小剂量给药组的HIF-1αmRNA显著降低;大剂量给药组较肾炎模型组HIF-1琢mRNA 的含量也显著降低。结论：氯沙坦可能可以通过影响低氧诱导因子（HIF-1α）的表达发挥对肾脏的保护作用。     

Experience with nimodipine treatment of vascular spasm after subarachnoid hemorrhage]

Pathogenesis of vasospasms following subarachnoid haemorrhage and possible therapeutic efficacy of nimodipine (calcium channel blocking agent) are discussed. The authors present their own experience in the treatment of 209 patients with subarachnoid haemorrhage with nimodipine. Collected clinical results suggest the necessity of the combined treatment of vasospasm following subarachnoid haemorrhage with nimodipine, hypervolemia, and hypertensive agents.     

硫酸软骨素酶ABC治疗减少大鼠脊髓损伤引起的酪氨酸蛋白激酶A4的表达

本研究旨在探讨大鼠脊髓损伤(spinal cord impairment,SCI)后硫酸软骨素酶ABC (chondroitinase ABC,ChABC)对酪氨酸蛋白激酶A4 (ephrin A4,EphA4)表达变化的影响.选取成年雌性SD大鼠,随机分为假手术组、生理盐水(NS)组和ChABC组.NS组和ChABC...     

肾血管性高血压大鼠模型中ET1和CGRP的变化

目的探讨降钙素基因相关肽（CGRP）及血浆内皮素（ET1）在高血压病中的作用。方法选用正常血压大鼠42只,随机分对照组、手术组、假手术组,分别观察血压值、CGRP及ET1值。结果手术组与正常组比较血压明显高于正常对照组（P〈0．01）,假手术组与正常对照组比较,血压无明显变化（P〉0．05）;手术组与对照组比较CGRP显著升高（P〈0．01）;假手术组与正常对照组比较,CGRP未见升高（P〉0．05）。手术组与对照组比较ET1无明显变化（P〉0．05）。结论CGRP在肾血管性高血压的发生发展中具有保护作用。ET1与CGRP是心血管系统中的一对拮抗因子,与CGRP的作用相反,ET1有较强的缩血管作用,从而导致血压升高。     

丙泊酚对全肝缺血再灌注大鼠脑损伤的保护作用及机制研究

目的:探究丙泊酚对全肝缺血再灌注(THIR)大鼠脑损伤的保护作用及机制。方法:选取72只健康成年雄性SD大鼠,将其按照抽签法分成假手术组、对照组以及丙泊酚组。所有大鼠予以12h禁食处理,采用3%戊巴比妥钠行腹腔注射麻醉处理,常规消毒后取上腹部正中切口进入腹腔。假手术组仅暴露肝门,不予以阻断处理。对照组与丙泊酚组则以无创动脉夹阻断肝固有动脉、门静脉和胆总管,在右肾动脉水平处阻断肝下下腔静脉,膈肌水平阻断肝上下腔静脉,进入全肝缺血阶段,阻断30 min后去除动脉夹恢复肝血流。其中丙泊酚组在全肝缺血前10 min予以丙泊酚50 mg/kg腹腔注射干预,假手术组与对照组则予以等量的生理盐水腹腔注射干预。比较三组大鼠再灌注24h后的脑组织细胞凋亡率、特异性半胱氨酸蛋白酶-3(Caspase-3)蛋白表达水平,脑组织超氧化物歧化酶(SOD)、丙二醛(MDA)、一氧化氮(NO)水平,血清白介素-6(IL-6)以及肿瘤坏死因子-α(TNF-α)水平。结果:对照组与丙泊酚组大鼠的细胞凋亡率及Caspase-3相对表达量均高于假手术组,而丙泊酚组细胞凋亡率及Caspase-3相对表达量均低于对照组(均P<0.05)。对照组与丙泊酚组大鼠脑组织SOD水平均低于假手术组,而丙泊酚组脑组织SOD水平高于对照组;对照组与丙泊酚组大鼠脑组织MDA、NO水平均高于假手术组,而丙泊酚组脑组织MDA、NO水平低于对照组(均P<0.05)。对照组与丙泊酚组大鼠血清IL-6、TNF-α水平均高于假手术组,而丙泊酚组血清IL-6、TNF-α水平均低于对照组(均P<0.05)。结论:丙泊酚可有效抑制THIR大鼠脑损伤引起的细胞凋亡,其主要机制可能与抑制Caspase-3表达、炎症反应以及抗自由基损伤有关。     

Increase in receptor binding affinity for nimodipine in the rat brain with permanent occlusion of bilateral carotid arteries

The permanent occlusion of bilateral common carotid arteries (2VO) in rats has been shown to cause progressive and long-lasting cognitive deficits which may be due to impairment of memory retention and/or memory recall process. To clarify the function of voltage dependent calcium channels and the receptor binding of nimodipine by chronic cerebral ischemia, we examined specific (+)-[3H]PN 200-110 binding and the effect of oral administration of nimodipine in brain regions and hearts of rats, at 2 weeks to 4 months after permanent 2VO. There was no significant difference in either dissociation constant (Kd) or maximal number of binding sites (Bmax) for (+)-[3H]PN 200-110 in the cerebral cortex, hippocampus, corpus striatum and thalamus between 2VO and sham rats. In addition, in vitro inhibitory effect of nimodipine on cerebral cortical (+)-[3H]PN 200-110 binding in 2VO rats was similar to that in sham rats. Compared to control rats, oral administration of nimodipine to both 2VO and sham rats at 2 months after permanent 2VO brought about a significant increase in Kd values of specific (+)-[3H]PN 200-110 binding in the cerebral cortex, hippocampus, thalamus and myocardium, and the increase in Kd values was much larger in brain regions of 2VO rats than sham rats. However, the increase in Kd values in the myocardium did not differ between 2VO and sham rats. This observation suggests an increased in vivo binding affinity for nimodipine in chronic ischemic brain. In conclusion, the present study has shown that oral administration of nimodipine may cause a greater occupation in vivo of 1,4-dihydropyridine (DHP) calcium channel antagonist receptors in brains of permanent 2VO rats than in sham rats. Thus, nimodipine may be pharmacologically effective in preventing brain dysfunction due to cerebral ischemia in vivo.     

miR-126调控脑缺血大鼠细胞凋亡机制的研究

摘要 目的：探讨脑缺血大鼠microRNA-126（MiR-126）在脑组织和血浆中表达的动态变化及与细胞凋亡的关系。方法：健康雄性SD大鼠45只随机分为3组,其中3只大鼠不作任何处理,用于检测正常大鼠中MiR-126在脑组织和血浆的表达,剩余大鼠随机分为假手术组和模型组,模型组用线栓法造脑缺血大鼠模型。TTC法检测模型组大鼠脑组织梗死病变用以确定造模是否成功;RT-qPCR检测大鼠造模后1、3、6、9、12、24和48小时脑组织和血浆中MiR-126的动态表达变化;采用苏木精-伊红染色法检测脑组织形态学变化;采用Western blot 方法分析相关凋亡蛋白表达的变化。结果：TTC法和H-E染色结果表明,大鼠脑缺血造模成功,模型组大鼠出现脑组织大面积梗死病变;MiR-126和Caspase-3表达在模型组大鼠脑组织和血浆中随着脑缺血时间的延长其表达水平逐渐提高,24 h到达高峰后,在48 h Mi-R126表达强度又降低,但仍然高于假手术组大鼠水平;Caspase-3在正常对照组和假手术组表达量都较少（P>0.05）,其他凋亡蛋白Bax和 STAT3相对表达水平趋势同 Caspase-3相似;而Bcl-2表达水平明显降低,趋势与其他凋亡蛋白相反。结论：MiR-126在脑缺血大鼠脑组织和血浆中表达水平明显升高,而且细胞凋亡明显增加,因此MiR-126可能通过促进细胞凋亡对脑缺血大鼠有保护作用,此研究为脑缺血发病机制和诊断提供更多依据。