辛伐他汀对兔脑血管痉挛中炎性反应的影响

目的探讨辛伐他汀对兔蛛网膜下腔出血（SAH）后脑血管痉挛（CVS）中炎性反应的影响。方法36只新西兰大白兔随机分为3组,每组12只。①对照组：给予常规饲养并枕大池二次注入等渗盐水;②sAH组：通过枕大池二次注血法建立SAH模型;③SAH＋辛伐他汀组：对SAH兔经胃灌注辛伐他汀5mg·kg^-1·d^-1,连续7d。在各组兔造模前后,行两次脑血管造影。第2次脑血管造影后1d,取基底动脉组织制作病理切片,分别于光镜和透射电镜下观察其显微及超微结构。行免疫荧光染色后,采用共聚焦显微镜观察基底动脉内皮细胞核转录因子-κB（NF—kB）表达量的变化,同时采用实时荧光定量PCR技术检测其细胞间黏附分子1（ICAM-1）mRNA的表达。结果①脑血管造影显示二次注血后,SAH组兔基底动脉出现明显的痉挛,管径变细,SAH组的管径为（0．68±0．09）mm,对照组为（0．87±0．06）mm,P〈0．05;而给予辛伐他汀后,痉挛减轻,SAH＋辛伐他汀组的管径为（0．77±0．08）mm,与SAH组管径比较,P〈0．05。SAH组兔基底动脉壁略有增厚,电镜显示平滑肌细胞内合成旺盛;而给予辛伐他汀预处理后,这些变化明显减轻。@SAH组兔基底动脉管壁内皮细胞内NF—κB表达高于对照组（156±9和84±8,P〈0．05）,而给予辛伐他汀后,NF—κB表达量降低（118±9）,与SAH组比较,P〈0．05。SAH组兔基底动脉组织ICAM-1mRNA的表达量高于对照组（0．843±0．029和0．673±0．011,P〈0．05）;给予辛伐他汀后,基底动脉ICAM-1mRNA的表达量低于SAH组（0．763±0．037）,与SAH组比较,P〈0．05。结论辛伐他汀可能通过抑制炎性反应从而预防SAH后CVS的发生,其抑制炎性反应,可能是通过NF—κB信号途径实现的。     

罗格列酮通过激活PPARγ改善肺动脉高压大鼠肺血管病变的研究

目的探讨过氧化物酶体增殖物激活受体γ（PPARγ）及其配体对野百合碱诱导的肺动脉高压大鼠肺血管病变的作用及机制。方法将40只SD大鼠随机分为4组：正常对照组、罗格列酮对照组、野百合碱组和罗格列酮干预组。野百合碱组和罗格列酮干预组给予野百合碱60mg／kg皮下注射;2个对照组给予等体积生理盐水皮下注射。罗格列酮对照组和罗格列酮干预组自注射生理盐水或野百合碱后,给予罗格列酮生理盐水混悬液（4．0mg·kg^-·d^-1）灌胃,正常对照组和野百合碱组每日给予等体积生理盐水灌胃,共4周。以右心导管测定右室收缩压（RVSP）和肺动脉平均压（mPAP）,计算右心肥厚指数（RVHI）作为评价右心室肥厚的指标;ELISA法测定血浆N0和内皮素-1（ET-1）水平;采用HE及Elastin Van Gieson染色法观察各级肺动脉的病理改变,测定并计算中膜厚度百分比（WT％）评价血管重塑程度;免疫组织化学法观察PPARγ的表达情况。结果罗格列酮干预组mPAP（28．2±5．3）mmHg、RVHI（0．35±0．05）和WTO（27．7±7．2）％较野百合碱组明显改善,但仍高于正常对照组。与野百合碱组比较,罗格列酮干预组可升高血浆NO水平（t=2．363,P〈0．05）、降低ET-1水平（t=3．522,P〈0．01）,并抑制肺小血管壁的增厚（t=5．192,P〈0．01）。结论罗格列酮可通过激活PPARγ改善野百合碱诱导的肺动脉高压大鼠肺血管重塑,并延缓肺动脉高压的进展。     

CT血管造影评价兔基底动脉痉挛模型

目的探讨采用多层螺旋CT血管造影（multi-slices CT angiography，MSCTA）技术显示兔基底动脉，为兔脑血管痉挛（cerebralvasospasm，CVS）动物模型建立新的评价方法。方法取日本大耳白兔25只，分为对照组（5只）和蛛网膜下腔出血（subarachnoid hemorrhage，SAH）组（20只）。SAH组采用枕大池二次注血法制作兔脑基底动脉CVS模型，均经兔耳后中央静脉穿刺注射非离子型对比剂（碘海醇，含碘量300mg／m1），剂量按2．6ml／kg（体重）。采用高压注射器给药，注射速度0．4ml／s，延时15S开始扫描。SAH组于注血后1、4、7、11d，行2～5次基底动脉MSCTA。原始图像三维后处理技术采用容积重建（volume rendering，VR）。结果SAH组注血后1、4、7、11d基底动脉直径分别为（1．28±0．36）、（0．82±0．24）、（0．83±0．20）及（0．95±0．28）mm。VR法测得实验兔注血前基底动脉横径平均为（1．30±0．40）mm。CVS在注血后第1天出现，第4天达到高峰，第11天可见基底动脉痉挛有一定程度的缓解。结论MSCTA技术能够较理想地显示兔基底动脉，是评价活体动物CVS模型的可靠方法。     

吡咯烷二硫代氨基甲酸盐对兔脑血管痉挛的作用

目的观察吡咯烷二硫代氨基甲酸盐（PDTC）对兔蛛网膜下腔出血（SAH）后脑血管痉挛的影响及NF—κBp65、ICAM-1在基底动脉的表达。方法新西兰大白兔48只（雌雄不限）。随机分为对照组（8只）、SAH组（20只）及PDTC组（20只）。SAH组和PDTC组又分为SAH后1、3、5、7、14d亚组,每组4只。采用枕大池二次注血法制作SAH模型。PDTC组在第2次注血后即脑池内注射PDTC,0．25ml／次,2次／d,连续2d。观察基底动脉管径和厚度、病理形态学改变;免疫组化检测NF—κBp65、细胞间黏附分子1（ICAM-1）的表达。结果①SAH组在第3天开始出现基底动脉管径变细、管壁增厚,第7天最明显,与第1天比较,差异有统计学意义（P〈0．05,P〈0．01）;PDTC组仅第7天与第1天比较有差异（P〈0．05）。在第3、5、7天时,SAH组与对照组及PDTC组比较上述指标,差异均有统计学意义（P〈0．05,P〈0．01）;PDTC组与对照组比较,差异均无统计学意义。（2）PDTC组与SAH组同时间点比较,病理形态损害、炎性细胞浸润程度减轻。③SAH组在第3天开始出现NF—κBp6、ICAM—1表达,第7天达高峰。第3、5、7d（ICAM-1包括第14d）,SAH组表达量均明显高于对照组和PDTC组（P〈0．01）。PDTC组与对照组比较亦增高,P〈0．05。结论PDTC对SAH后迟发性脑血管痉挛具有一定的预防作用。通过抑制NF—κBp65、ICAM-1的表达可能是其机制之一。     

罗格列酮对破骨细胞生成的影响

目的探讨罗格列酮对破骨细胞生成的影响。方法取C57BIM6小鼠骨髓内单个核细胞,用细胞核因子kappaB受体活化因子配基（RANKL）及巨噬细胞集落刺激因子（M—CSF）诱导其向破骨细胞分化,在诱导开始时即分成3组：空白对照组（G1）,0．5μmoL／L罗格列酮组（G2）,2．0μmol／L罗格列酮组（G3）,诱导结束后进行抗酒石酸酸性磷酸酶（TRAP）染色、检测TRAP活性以及实时PCR检测相关基因的表达。应用单因素方差分析进行统计学分析。结果破骨细胞生成的数目在G2组[（54±5）个]、G3组[（72±5）个]均高于G1组[（32±5）个],差异有统计学意义（F=82．43,P〈0．05）,TRAP活性也高于对照组（G1：2．32±0．14,G2：2．83±0．08,G3：3．35±0．10,F=108．12,P〈0．05）;过氧化物酶增殖物激活受体-γ（PPAR-γ）、组织蛋白酶K、c-fos与c-jun基因表达也高于对照组,且随着罗格列酮的浓度升高,相关基因的表达也增高（F值分别为33．50、37．46、53．73、39．77,均P〈0．05）。结论罗格列酮可能通过促进细胞增殖而促进破骨细胞生成,这司能是罗格列酮导致骨丢失的重要原因之一。     

PPAR-γ激动剂对急性坏死性胰腺炎大鼠肺损伤的作用

目的 探讨过氧化物酶体增殖物激活受体γ(PPAR-γ)激动剂罗格列酮对ANP大鼠肺损伤的作用及其机制.方法 雄性Wistar大鼠54只,按完全随机法分为假手术组(SO组)、ANP组、罗格列酮组.胆胰管逆行注射5%牛磺胆酸钠制备ANP模型.SO组、ANP组在造模前30 min股静脉注射10%DMSO(0.2 ml/100 g体重);罗格列酮组则注射等量10%DMSO溶解的罗格列酮(6 mg/kg体重).术后3 h、6 h、12 h分批剖杀,每个时间点6只.检测血清淀粉酶、肺组织髓过氧化物酶(MPO)、肺湿干重比、支气管肺泡灌洗液(BALF)蛋白含量.取胰头部胰腺组织和肺组织行病理学检查.RT-PCR检测肺组织TNF-α mRNA和ICAM-1 mRNA的表达.结果 ANP组血淀粉酶、肺MPO、湿干重比、BALF蛋白含量、胰腺及肺病理分值、肺脏TNF-α mRNA和ICAM-1 mRNA的表达水平均随时间延长而逐渐升高,12 h时分另0为(5353.0±728.2)U/L、(1.12±0.14)U/g、3.00±0.14、(0.438±0.056)g/L、11.17±0.93、8.17±0.75、0.57±0.03和1.53±0.08,均明显高于SO组(P<0.05或P<0.01).罗格列酮12 h组上述指标分别为(2847.4±841.0)U/L、(0.84±0.06)U/g、2.13±0.36、(0.283±0.078)g/L、7.75±0.27和4.33±0.82、0.26±0.04和0.84±0.02,均明显低于ANP 12 h组(P<0.05或P<0.01),但仍高于SO组(P<0.05或P<0.01).结论 罗格列酮对ANP大鼠胰腺及肺损伤具有一定程度保护作用,其机制可能与抑制肺组织TNF-α、ICAM-1 mRNA的表达有关.     

PPARγ激动剂对自发性高血压大鼠基质金属蛋白酶2的影响

目的：观察过氧化物酶体增殖物激活受体γ（PPARγ）激动剂罗格列酮对自发性高血压大鼠（SHR）心、肾、动脉血管基质金属蛋白酶2（MMP-2）表达及活性的影响，探讨罗格列酮心血管保护作用的机制。方法：健康雄性12周龄SHR大鼠12只，体重245～255g，随机被分为2组：对照组及罗格列酮组（5mg／kg·d），每组6只。应用实时多聚酶链氏反应（PCR）、Western印迹法、明胶酶谱法（zymography）等方法对用药4周后的SHR心、肾、动脉MMP-2的表达进行测定。结果：罗格列酮治疗能使SHR心、肾MMP-2 mRNA的表达降低97．6％和58．9％（P〈0．01，P〈0．05），使胸主动脉、颈动脉MMP-2的活性降低30．7％和24．6％（P〈0．05），而蛋白表达无明显差异。结论：罗格列酮治疗逆转SHR靶器官损害的作用机制可能与降低MMP-2的作用有关。     

罗格列酮对大鼠溃疡性结肠炎肠黏膜NF-κB,ICAM-1表达的影响

目的:探讨罗格列酮对大鼠溃疡性结肠炎肠黏膜核转录因子-κB(NF-κB),细胞间黏附分子-1(ICAM-1)表达的影响.方法:应用三硝基苯磺酸(TNB)/乙醇灌肠制备大鼠溃疡性结肠炎模型.实验设正常对照组,模型对照组,阳性药物组(柳氮磺吡啶SASP组,100mg/kg),罗格列酮组(2,4,8mg/kg),每天灌胃给药1次,给药时间从造模后第2天开始至实验结束共8d,观察大鼠疾病活动指数(DAI)和结肠黏膜损伤指数(CMDI),生化法检测大鼠结肠组织髓过氧化酶(MPO)活性,免疫组化法检测大鼠肠黏膜NF-κBp65和ICAM-1蛋白的表达.结果:与正常组相比,模型组DAI、CMDI评分及结肠组织MPO活性明显升高(2.11±1.29vs0.11±0.17,2.67±0.82vs0.33±0.52,1.26±0.36U/gvs0.27±0.07U/g,P<0.01),结肠黏膜NF-κBp65及ICAM-1表达明显增强(0.7081±0.0671vs0.2293±0.0474;0.4846±0.0366vs0.1783±0.0201,P<0.01).罗格列酮中、高剂量组DAI,CMDI评分及MPO活性较模型组有明显下降(DAI:1.11±0.50,0.61±0.25vs2.11±1.29,P<0.05;CMDI:1.67±0.52,1.17±0.75vs2.67±0.82,P<0.05;MPO:0.82±0.13,0.51±0.10U/gvs1.26±0.36U/g,P<0.01),NF-κB及ICAM-1表达也有不同程度降低(NF-κB:0.4544±0.0379,0.2577±0.0131vs0.7081±0.0671,P<0.01;ICAM-1:0.3854±0.0277,0.2830±0.0234vs0.4846±0.0366,P<0.01).大鼠结肠黏膜NF-κB的表达与ICAM-1表达呈正相关(r=0.927,P<0.01),ICAM-1的表达与结肠组织MPO活性也呈正相关(r=0.580,P<0.01).结论:罗格列酮对大鼠溃疡性结肠炎有保护作用,其作用机制可能与抑制NF-κB活化,减少黏附分子ICAM-1产生以及降低中性粒细胞浸润有关.     

R－型钙通道阻滞剂对大鼠蛛网膜下腔出血后脑动脉钙通道相关蛋白的影响

目的研究蛛网膜下腔出血（SAH）后脑动脉R-型钙通道的表达情况,并探讨R-型钙通道阻滞剂——SNX-482对脑动脉收缩相关蛋白的作用。方法20只雄性SD大鼠,随机分为假手术组、SAH组、SAH＋尼莫地平组、SAH＋SNX-482组,每组5只。采用大鼠鞍上池注射自体动脉血法制备SAH模型,其后第1、2日每天向假手术组和SAH组的脑池内注射25μl等渗盐水,向SAH＋尼莫地平组和SAH＋SNX-482组注射25μl尼莫地平或SNX-482。第3日取脑动脉标本,后经SDS-聚丙烯酰胺凝胶电泳和蛋白印迹半定量检测R-型钙通道蛋白和调宁蛋白（calponin）的表达水平,经尿素甘油-聚丙烯酰胺凝胶电泳和蛋白印迹检测肌球蛋白轻链2（MLC2）磷酸化百分比。结果①假手术组、SAH组、SAH＋尼莫地平组和SAH＋SNX-482组R-型钙通道蛋白相对量分别为0．38±0．08、0．86±0．07、0．66±0．11和0．72±0．09,假手术组的蛋白相对量均低于其他三组（P〈0．05）;②上述各组calponin相对量分别为2．32±0．14、0．54±0．17、0．75±0．19和1．42±0．15,各组间差异均具有统计学意义（P〈0．05）;③上述各组MLC2磷酸化百分比依次为12．2±2．8、41．0±3．2、36．1±2．8和25．3±1．9,除SAH和SAH＋尼莫地平两组外,其余各组间差异均具有统计学意义（P〈0．05）。结论R-型钙通道阻滞剂可抑制SAH大鼠脑动脉的calponin降解和MLC2磷酸化的程度,其作用强于L-型钙通道阻滞剂尼莫地平。     

罗格列酮对大鼠重症急性胰腺炎NF-κB和ICAM-1的作用

目的探讨大鼠重症急性胰腺炎（SAP）时罗格列酮对核因子-κB（NF-κB）和细胞间黏附分子-1（ICAM-1）的作用。方法急性胰腺炎模型组（SAP组）逆行胆胰管注射牛磺胆酸钠建立大鼠SAP模型;假手术组（SO组）逆行胆胰管注射等量生理盐水;罗格列酮组（R组）于造模前30min给予罗格列酮。检测血清淀粉酶（AMY）的变化,取胰头部胰腺组织行病理学检查;免疫组化检测胰腺组织NF-κB和ICAM-1的表达情况。结果SAP组各时间点AMY、胰腺组织病理评分及NF-κB和ICAM-1的表达较SO组增高（P〈0．01）;R组各时间点上述指标较SAP组均下降,但仍高于SO组（P〈0．01）;NF-κB和ICAM-1两者在SAP组和R组具有相关性（P〈0．01）。结论罗格列酮能减轻大鼠SAP胰腺病理损伤,其机制可能与通过抑制NF-κB的活性、降低ICAM-1的表达有关。     

米力农对兔蛛网膜下腔出血后脑血管痉挛的作用及其机制研究

目的探讨米力农对兔蛛网膜下腔出血(SAH)后脑血管痉挛的作用及其机制。方法取3个月龄日本大耳白兔32只,随机分为SAH组、对照组、米力农组及米力农+N-硝基-左旋精氨酸甲酯(L-NAME)组,共4组,每组8只。采用枕大池二次注入自体血建立SAH模型。向对照组兔枕大池内注入等渗盐水替代自体血,其他操作同SAH组。在SAH造模后30 min,对米力农组兔由耳源静脉注射米力农溶液5 ml(30μg/kg);米力农+L-NAME组,先经耳源静脉注射米力农溶液(30μg/kg),再注射L-NAME(30 mg/kg),共5 ml;对照组、SAH组注射等渗盐水5 ml。对4组兔均连续给药3 d,1次/d。术后第3天应用CT血管造影(CTA)和经颅多普勒超声(TCD)观察各组兔基底动脉的管径和血流速度。结果 TCD检查显示,对照组、SAH组、米力农组、米力农+L-NAME组基底动脉的平均血流速度分别为(19.4±1.8)、(32.7±4.2)、(17.8±1.8)及(33.2±7.2)cm/s;收缩期峰值流速分别为(27±5)、(45±4)、(29±3)及(44±4)cm/s。CTA检查显示,4组基底动脉管径分别为(1127±140)、(772±116)、(1113±101)及(802±91)μm。上述指标各组间比较,差异均有统计学意义,P<0.01。结论米力农对SAH后脑血管痉挛有缓解作用,其扩血管作用可能与L-NAME抑制一氧化氮合酶活性有关。     

红细胞生成素治疗兔脑血管痉挛及对核因子κB表达的影响

目的探讨红细胞生成素（EPO）对兔蛛网膜下腔出血（SAH）后迟发性脑血管痉挛（CVS）的疗效及其对核因子κB（NF-κB）表达的影响。方法取雄性新西兰白兔36只,随机分为对照组、SAH组和EPO治疗组,每组12只。采用枕大池二次注血SAH模型诱发迟发性CVS。EPO注射剂量为1000IU/kg,1次/8h;对照组和SAH组均给予EPO的溶剂（含人血清蛋白2.5mg/ml、氯化钠352mmol/L及蒸馏水）,以1ml/kg经腹腔注射,连续腹腔注射15次。造模后第5天处死动物,取基底动脉,采用HE染色测定基底动脉管腔横截面积,并用凝胶电泳迁移分析法检测NF-κB活性。结果①对照组、SAH组和EPO治疗组兔的基底动脉管腔横截面积分别为（0.412±0.034）、（0.210±0.018）和（0.342±0.030）mm2。SAH组与对照组比较,P〈0.01;EPO治疗组与SAH组比较,P〈0.01,与对照组比较,P〈0.05。②对照组、SAH组和EPO治疗组的NF-κB活性灰度值分别为：1.20±0.11、9.30±1.12和6.60±0.13,SAH组与对照组比较、EPO治疗组与对照组和SAH组比较,差异均有统计学意义（P〈0.01）。结论EPO能够缓解SAH后的迟发性CVS,并抑制SAH后血管中NF-κB的表达。     

Preliminary report: Effect of cobaltous ion on cerebral vasospasm in a rabbit subarachnoid hemorrhage model

Experimental studies have suggested what the primary role is of free radical products in the development of vasospasm. It has been suggested that the degradation products of hemolysis trigger free radical reactions leading to lipid peroxidation is subarachnoid hemorrhage (SAH). Therefore, Fe²⁺, a degradation product of hemoglobin, seems to be the most important substance in the pathogenesis of vasospasm. Cobaltous ion was shown to be a powerful inhibitor of lipid peroxidation in biological membrane. Eleven rabbits were anesthetized and received 5 ml of autologous arterial blood into the cisterna magna. Group 1 (n=6) received 0.1 mg/kg cobalt solution intratecally via the cisterna magna simultaneously with blood. Group 2 (n =5) underwent sham operation as a control group. Forty-eight hours later the rabbits were deeply anesthetized and the brainstem was quickly removed and put under the operating microscope to measure the basilar artery diameter. Afterwards, the upper part of the brainstem was used for lipid peroxidation measurement and the lower part for the histopathological examination. Significant vasospasm was observed in four and moderate vasospasm in one rabbit of group 2; mild vasospasm was seen in five rabbits and moderate vasospasm was seen in one rabbit of group 1. There was no vasospasm in the control group. A statistically significant increase in the levels of lipid peroxide was found in the brainstem of group 2. These data demonstrate that cobaltous ion represents a promising therapeutic tool in vasospasm after SAH.     

脑红蛋白对蛛网膜下腔出血大鼠早期脑损伤的保护作用

目的探讨脑红蛋白（NGB）对蛛网膜下腔出血（SAH）大鼠早期脑损伤的保护作用。方法将60只清洁级sD大鼠随机分为4组：正常组、假手术组、SAH组、治疗组（SAH＋腹腔注射氯化血红素）组。除SAH组30只外,其余每组10只大鼠。采用枕大池单次注血法建立大鼠SAH模型。采用免疫组化法和图像分析技术观测SAH后,不同时间大脑皮质颞叶的NGB免疫组化反应及平均吸光度A值;采用干湿法测量脑含水量,原位细胞凋亡检测法（TUNEL）检测颞叶神经元凋亡情况。结果①正常组和SAH后24h组平均吸光度4值分别是0．133±0．021和0．236±0．028：②sAH后颞叶皮质NGB阳性反应细胞迅速增加,24h达高峰,随后逐渐减少;③SAH组脑含水量为（77．5±0．4）％,治疗组脑含水量为（76．5±0．6）％,治疗组脑含水量较SAH组减少,差异有统计学意义（P〈0．05）;④治疗组和SAH组脑颞叶神经元凋亡程度为（9．8±2．4）％、（18．5±2．3）％。治疗组脑皮质神经元凋亡程度较SAH组降低（P〈0．05）。结论SAH后大鼠大脑皮质NGB阳性反应细胞呈动态变化。早期给予NGB能减少大鼠SAH模型的皮质神经元凋亡,降低脑水肿程度,具有明显的脑保护作用。     

Involvement of Rho-kinase-mediated phosphorylation of myosin light chain in enhancement of cerebral vasospasm

Subarachnoid hemorrhage (SAH) often induces a long-term narrowing of the cerebral artery called cerebral vasospasm. Myosin light chain (MLC) in the spastic basilar artery was reported previously to be phosphorylated by Ca(2+)/calmodulin-dependent MLC kinase. Because Rho-kinase, which is activated by the small GTPase Rho, phosphorylates not only MLC but also myosin phosphatase at its myosin-binding subunit (MBS), thus inactivating myosin phosphatase, we examined whether Rho-kinase is involved in the development of vasospasm. Cerebral vasospasm was produced in the canine basilar artery by a 2-hemorrhage method, and vasocontractions were induced by topical application of 80 mmol/L KCl or 0.5 micromol/L serotonin to the canine basilar artery exposed transclivally. The phosphorylation of MLC in the basilar artery was increased concurrently with an enhancement in the intensity of vasospasm with the passage of time after SAH. In addition, Rho-kinase in the basilar artery was activated concurrently with an increase in the phosphorylation of MBS at Ser854 in vasospasm. The Rho-kinase activation levels in vasospasm on days 0 and 2 were comparable to those in KCl- and serotonin-induced sustained vasocontraction, respectively, and those in vasospasm on day 7 were markedly high. The topical application of Y-27632, a specific inhibitor of Rho-kinase, to the exposed spastic basilar artery on day 7 induced a dose-dependent dilation, and the intensities of vasospasm and the phosphorylation of MBS and MLC were simultaneously decreased by 10 micromol/L Y-27632, although the decrease in MBS phosphorylation was more marked than the decrease in MLC phosphorylation. These results indicate that the activation of Rho-kinase and the phosphorylation of MLC and MBS occur concomitantly during vasospasm induced by SAH and suggest that Rho-kinase is involved in the enhancement of cerebral vasospasm in addition to Ca(2+)/calmodulin-dependent MLC kinase by increasing the phosphorylation of MLC directly or indirectly as a result of the inhibition of myosin phosphatase by its phosphorylation.     

Attenuation of canine cerebral vasospasm after subarachnoid hemorrhage by protein kinase C inhibitors despite augmented phosphorylation of myosin light chain

The purpose of the present study is to assess the roles of protein kinase C (PKC) isoforms, especially PKC delta and alpha, and 20-kD myosin light chain (MLC(20)) phosphorylation in the mechanism of cerebral vasospasm following subarachnoid hemorrhage (SAH). We had shown that those PKC isoforms are involved in the development of cerebral vasospasm. Using PKC isoform-specific inhibitors in a 'two- hemorrhage' canine model, we examined changes in the development of cerebral vasospasm, translocation of PKC isoforms and MLC(20) phosphorylation level in canine basilar arteries. A PKC inhibitor (5 microM rottlerin for PKC delta or chelerythrine for PKC alpha) was injected into the cisterna magna on day 4 before the second hemorrhage. The treatment was continued daily until day 7. Rottlerin inhibited the initial phase of vasospasm and PKC delta translocation, but did not significantly inhibit PKC alpha translocation. Chelerythrine inhibited cerebral vasospasm, and the translocation of both PKC delta and alpha throughout the entire course of the study. Although cerebral vasospasm after SAH was inhibited by each PKC inhibitor, the MLC(20) phosphorylation level remained elevated as in the untreated hemorrhage-control study. We conclude that cerebral vasospasm following SAH depends on PKC delta and alpha, while the enhancement of MLC(20) phosphorylation contributes little to this form of vasospasm.