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利多卡因对大鼠微栓栓塞致脑损伤的保护作用

时间:2010-08-24 11:35:28  来源:  作者:

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The protective effects of lidocaine on the brain against injury induced by microsphere embolism in rats

 

华震 王东信 吴新民 王沛玉

HUA Zhen,WANG Dong-xin,Xin-min,et a1. Department of Anesthesiology,First Hospital,Peking University,Beijing 100034, China

 

Abstract

  Objective:To investigate if lidocaine can alleviate the behavioral disorder,learning and memory dysfunction and neuropathological lesions induced by cerebral microsphere embolism.

  Methods:Sixty-five healthy male Wistar rats weighing 210-270 g were randomly divided into 5 groups:2 microsphere groups(n=14 each),2 lidocaine pretreatment groups(n=12,13)and control group(n=8).The animals were anesthetized with isoflurane,60% nitrous oxide and O2. In the microsphere groups 60O or 900 microspheres were injected into right internal carotid artery.In the lidocaine pretreatment groups a bolus of lidocaine 1.5mg/kg-1 was given via femoral vein 30 min before microsphere injection foHowed by lidocaine infusion at 2 mg/kg-1 /h-1 until 1h after microsphere injection.In control group vehicle without microsphere was infuected.The behavior score was recorded every day from the 1st to 7th day after microsphere injection. The Morris water maze test was performed 3 times a day starting from the 8th to 12th day after microsphere injection.The animals were sacrificed after the last water maze test.Brains were removed for microscopic examination of the hippocampus CA1 region.

  Results:1)The behavioral scores(0=no typical signs,9=worst resuhs)decreased with time after embolism in all groups and were significantly higher in the microsphere and lidocaine groups than in control group.They were significantly higher in microsphere group 2 than in microsphere group 1 and the two lidocaine groups(P<0.05,0.01).(2)In water maze test the latency periods shortened with time in all groups and were significantly shorter in lidocainegroup 2 than in microsphere group 2(P<0.01). The ratio of efective search strategy increased with timein all groups and was significantly higher in lidocaine groups 2 than in microsphere groups(P<0.05,0.1).(3)The number of is chemic dead neurons in hippocampus CAI region was significantly larger in microsl:Ihere and lidocaine groups than in control gro(P<0.05,0.01)and was significantly smaller in the lidocaine groups than in the microsphere groups(P<0.05).

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  Condusion:Lidocaine pretreatment has protective efect against the cerebral injury induced by microsphere embolism in rats.

  Key words:Lidocaine;Briain injuries;Intracranial embolism and thrombosis

 

  认知功能障碍是术后常见的中枢神经系统并发症,可导致病人恢复延迟、住院时间延长,并影响病人出院后的日常生活和工作[1,2]。脑微栓栓塞是导致心脏手术后认知功能障碍的主要原因之一[1,3],但目前尚无药物能有效地防治此并发症。利多卡因可降低冠脉搭桥手术后早期认知功能障碍的发生[4],推测与利多卡因减轻微栓栓塞所造成的脑损伤有关。本研究拟观察利多卡因对大鼠微栓栓塞致脑损伤的保护作用并探讨其机制,为临床研究提供参考。

 

材料与方法

  动物选择及分组 健康雄性Wistar大鼠65只,体重210~270g(北京维通利华实验动物中心提供)。随机分为5组,对照组(n=8):经右侧颈动脉注射2O%葡聚糖(微球载体);微栓1组(n=14)和微栓2组(n=14),分别注射600和900个微球;保护1组(n=12)和保护2组(n=13),分别注射600和900个微球,并给予利多卡因。另取雄性Wistar大鼠4只用于测定利多卡因血药浓度。

  微球栓塞大鼠模型[5] 大鼠吸人3%异氟醚、60%氧化亚氮和氧气的混合气体麻醉诱导。翻正反射消失后保持自主呼吸,异氟醚浓度维持于1%~1.5%。保温毯加热,直肠温维持于37.5~38.5℃。尾动脉穿刺置管持续测定有创血压;分别于微栓注人前10min和注人后20min抽取动脉血行血气分析和血糖测定。右股静脉穿刺置管。颈部正中切口,暴露并阻断右侧颈外动脉和翼腭动脉,右颈总动脉穿刺置管以备注射微球或载体。微球(NEM.005,Perkin.Elmar公司,美国)直径47~48m,以20%葡聚糖(Pharmcia公司,美国)为载体,总量150l,沿动脉血流方向在30S内缓慢匀速注射。注射完毕拔出导管后用外科胶止血,恢复颈外动脉和翼腭动脉血流,缝合伤口。微球注射过程中无渗漏;实验毕解剖鼠脑,微球在栓塞侧大脑半球弥散分布为模型建立成功标准。

  利多卡因给药 保护组大鼠于微球注人前30min经股静脉注射利多卡因(批号:LOP68H0139,Sigma公司,美国)1.5mg/kg负荷剂量,继以2mg/kg-1h-1持续输注直至微球注射后1h。其余组大鼠给予等量生理盐水。

  脑卒中行为评分 注射微球后第1~7天开始评分,每日在相同时间和环境中进行。以脑卒中大鼠的典型表现为评分标准[6],即在自主活动中出现行为活动减少、躯干偏斜、强迫转动。每项指标分值为0至3分:无典型症状为0分;轻度症状1分;中度症状2分;重度症状3分。最高累积分值为9分。

  水迷宫试验 大鼠Morris水迷宫[7]测试仪(上海吉量软件公司),平台置于西南象限水面下1.5cm。正式测试前一日将大鼠放人池中自由游泳90s,不放置平台。注射微球后第8~12天测试,每日3次,取其平均值。测试时将大鼠随机从3个不同入水点(西北、东北、东南象限中点)面向池壁放入水中,图像自动监视系统追踪大鼠的游泳轨迹(每次≤90s),记录大鼠找到固定平台的时间(潜伏期)。如果大鼠找到平台,允许其在平台上停留10s;如果90s内未找到平台,则记录为90s并将其引导至平台上停留10s。平台停留后放人笼中休息10min,开始下一次测试。每日3次成绩的平均值为当日成绩。直线式和趋向式游泳轨迹为有效搜索策略,边缘式和随机式为无效搜索策略,记录每日有效搜索策略比例。

  神经病理检查 水迷宫试验结束后,各组随机取3只大鼠,腹腔注射水合氯醛0.45g/kg麻醉后,经主动脉快速灌注生理盐水100ml,继以4%多聚甲醛(4℃)150rnl快速灌注和150ml持续灌注lh。取出鼠脑后在4%多聚甲醛中继续固定24h。标本进行石蜡包埋,前囱后4.4mm处行冠状切片,每个标本切取4张海马切片,HE染色。光镜下(10×20倍),在海马CAI区锥体细胞层连续摄取4个视野,计数4个视野内正常神经元和缺血坏死神经元数量。

  利多卡因血药浓度的测定 另取雄性Wistar大鼠4只,按上述剂量及速率给予利多卡因,输注75min(相当于微栓注入后45min)时经尾静脉抽血3ml,用高压气相色谱法(GC-7A型色谱仪,Shimadzu公司,日本)测定利多卡因血药浓度[8]

  统计学处理 采用SPSS11.0统计学软件,正态分布的计量资料以均数±标准差(x±s)表示,方差齐时组问比较采用单因素方差分析,组内比较采用双因素方差分析;非正态分布的计量资料以中位数[M(最小值~最大值)]表示。方差不齐或非正态分布资料采用Kruskal-Wallis H检验和秩和检验。P<0.05为差异有统计学意义。

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结 果

  微栓栓塞后24h内,微栓1组有1只大鼠死亡,微栓2组有2只大鼠死亡,保护1组有1只大鼠死亡,其余存活大鼠均完成实验。实验结束后,解剖鼠脑发现,微球在栓塞侧大脑半球弥散分布,表明微栓栓塞的模型成功建立。

  动物的体重以及栓塞前10min和栓塞后20mi时平均动脉压、动脉血气和血糖组间比较差异无统计学意义(P>0.05)。

  各组动物的行为评分随注射微球后时间延长而降低;微栓组和保护组的行为评分均高于对照组(P<0.05或0.01)。微栓2组在注射微球后第1~4天行为评分高于微栓1组;保护1组在注射微球后3、4天行为评分低于微栓1组;保护2组在注射微球后第1~4、6天行为评分低于微栓2组(P<0.05或0.01)。见表1。

  各组动物的潜伏期均随测试天数增加而缩短。注射微球后第12天潜伏期微栓2组长于对照组,而保护2组短于微栓2组(P<0.05或0.01)。各组动物的有效搜索策略比率均随测试天数增加而升高。微栓2组在注射微球后第12天有效搜索策略比率低于对照组,保护1组在注射微球后第2、5天有效搜索策略比率高于微栓1组,保护2组在注射微球后第9、12天有效搜索策略比率高于微栓2组(P<0.05或0.01)。见表2。

  标本制作过程中保护1组有一标本损坏。由于两个微栓组结果接近,将其结果进行合并。两个保护组的结果也进行合并。栓塞侧海马CA1区的正常神经元计数微栓组少于对照组(P<0.05),保护组与对照组比较差异无统计学意义;缺血坏死神经元计数微栓组和保护组高于对照组,但保护组低于微栓组(P<0.05或0.01),见表3。

  4只大鼠利多卡因的血药浓度为(2.20士0.18)ktg/ml。

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参 考 文 献

1. Seines OA,Golds borough MA,Borowicz LM,et a1.Neurobehaviouralsequelaes of cardiopulmonary bypass.Lancet.1999,353:1601-1606.

2. Newman MF,Grocott HP,Mathew JP,et a1. Report of the substudy assessing the impact of neuroeogn ifive function on qua1ity of life 5 years after cardiac surgery Stroke,2001,32:2874-2881.

3. Pugsley W,Klinger L,Paschalis C,et a1. The impact of microemboli during cardiopulmonary bypass on neuropsychological functioning. Stroke,1994,25:1393-1399.

4. Wang D,Wu X,Li J,et a1. Efect of lidocaine on early postoperative cognitive dysfunction after coronary artery bypass surgery.Anesth Analg,2002.95:1134-1141.

5. Takagi K,Takeo S. Th e model of stroke induced by microsphere embo-lism in rats. Nippon Yakurigaku Zasshi,2003,121:440-46

6. Furlow TW. Bass NH. Arachidonate.induced cerebrovascular occlusion in the rat. The role of plateleta and aspirin in stroke.Neurology,1976,26:297-304

7. Moms RG,Garrud P,Rawlins JN,et al. Place navigation impaired in rats with hippoc ampal lesions.Nature,1982,297:681-683.

8. Keenaghan JB.The determination of lidocaine and pfilocaine in whole blood by gas chromatography.Anesthesiology,1968,29:110-112.

9. Nagakura A,Takagi N,e0 S.Impairment of cerebral cAMP-mediated signal tranaduction system and of spatial memory function after micresphero embolism in rats.Neuroscience,2002,113:519-528.

10. Takagi N,Miyake K,Tagnchi T,et a1.Changes in cholinergic neurons and hiluro in learning function after micresphero embolism-induced cerobral ischemia. Brain Res Bull,1997,43:87-92.

11. Wang D,Wu X,Zhong Y,et a1. Efect of lidocaine on improving cerebral protection provided by retrograde cerebral perfusion:a neuropathologic study.J Cardiothorac Vasc Anesth,1999,13:176-180.

12. Lei B. Cottrell JE,Kass IS.Neuroproteetive efect oflOW-dose lidocalne in a rat model of tran sient focal cerobral ischemia. Anesthesiology,2OO1,95:445-451.

13. Fried E,Amorim P,Chambers G,et al. The importance of sodium for an oxic transmission damage in rat hippoc ampal slices:mechan isms of protection by lidocaine. J Physiol,1995,489:557-565.

14. Sakabe T. Maekawa T,Ishikawa T,et a1.The efects of lidocaine on can ine cerobral metabolism and circulation rolated to the  electroencephalogram. Anesthesiology. 1974,40:433-441.

15. Taylor CP,Burke SP,Weber ML.Hippocampal slices:glutⅢ te overflow and cellular damage from ischemia are reduced by sodium-channel blockade.J Neuresci Metheds,1995,59:121-128.

16. LerLfant F,Lahet JJ,Courderot Mesuyer C,etal docmne has better antioxidant potential than ropivacaine and bupivacaine:in vitro comparison in a model of human erythrocytes submitted to in oxidative stres.Biomed Pharmacother,2OO4,58:248-254.

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