异氟醚预处理对大鼠局灶性脑缺血损伤的保护作用

目的探讨异氟醚预处理能否诱导脑缺血耐受产生。方法30只雄性SD大鼠(350～400g)，随机分为三组对照组(n＝10)，动物不接受任何处理；Iso/5d／1h组(n＝10)，动物每天接受1h的异氟醚预处理(2％异氟醚，98％氧)，连续5d；O2／5d／1h组(n＝10)，动物每天接受1h的吸氧处理(98％氧，无异氟醚)，连续5d。所有动物均采用右侧颈动脉丝线栓塞大脑中动脉致局灶性脑缺血120min，观察再灌注后1，3，6，12，16，24h动物神经行为学改变及24h时脑梗死容积。结果术后各时间点神经行为学评分Iso／5d／1h组明显低于对照组和O     

七氟醚预处理对大鼠局灶性脑缺血-再灌注损伤的保护作用

目的观察七氟醚预处理对大鼠局灶性脑缺血一再灌注损伤的保护作用。方法32只雄性SD大鼠随机均分为四组,假手术组：仅分离血管,不留置线栓;Sevol、Sevo2和对照组：分别在缺血前吸入2％、3％七氟醚和纯氧30min。用左颈内动脉尼龙线线栓法使大脑中动脉阻闭120min,拔出尼龙线恢复再灌注。观察再灌注24h后神经功能损害改变并评分,然后处死动物取大脑行2,3,5-氯化三苯基四氮唑（TTC）染色以测量脑梗死体积。结果缺血-再灌注损伤后对照组大鼠神经功能损害较Sevol和Sevo2组更明显（P〈0．05或P〈0．01）。缺血-再灌注损伤24h后Sevo1组和Sevo2组脑梗死体积和梗死体积百分比,较对照组减小（P〈0．01）。结论缺血前吸入2％、3％七氟醚对大鼠局灶性脑缺血-再灌注损伤可产生保护作用。     

异氟醚调控Toll样受体4/核因子-κB信号通路保护大鼠肾缺血再灌注损伤

目的探讨异氟醚对肾缺血再灌注损伤(ischemic reperfusion injury, IRI)的保护作用及相关分子机制。方法 32只大鼠按随机数字表法分为假手术组(S组)、肾缺血再灌注损伤组(IRI组)、异氟醚预处理组(Iso+IRI组)和异氟醚+脂多糖组(Iso+IRI+LPS组), 每组8只。Iso+IRI组进行异氟醚(isoflurane, Iso)预处理, Iso+IRI+LPS组进行Iso预处理后腹腔注射脂多糖(lipopolysaccharide, LPS)0.1 mg/kg, 其他组同时注射同体积生理盐水。而后IRI组、Iso+IRI组及Iso+IRI+LPS组采用夹闭肾蒂法建立肾IRI模型, S组进行假手术。术后24 h检测大鼠静脉血Cr和BUN水平, ELISA法检测肾组织IL-1β、TNF-α、IL-6水平, 超氧化物歧化酶(superoxide dismutase, SOD)活性检测试剂盒检测肾组织SOD活性, 可见分光光度法检测肾组织丙二醛(malondialdehyde, MDA)、谷胱甘肽过氧化物酶(glutathion peroxidase, GSH...     

七氟醚预处理对大鼠脊髓缺血再灌注损伤的影响及自噬在其中的作用

目的 评价七氟醚预处理对大鼠脊髓缺血再灌注损伤的影响及自噬在其中的作用.方法 成年雄性SD大鼠45只,体重420～450 g,采用随机数字表法分为5组(n=9):对照组(Con组)、脊髓缺血再灌注组(I/R组)、七氟醚预处理组(Sevo组)、特异性自噬抑制剂3-甲基腺嘌呤组(3-MA组)和3-MA+七氟醚预处理组(3-MA+ Sevo组).I/R组胸主动脉球囊阻断+体循环低血压制备大鼠脊髓缺血再灌注模型,Sevo组于缺血前24h时吸入3.4％七氟醚2h,3-MA组和3-MA+ Sevo组分别于再灌注即刻和吸入七氟醚前15 min时鞘内注射20出3-MA(10 mmol/L).于再灌注24h时采用神经功能缺陷评分(NDS评分)法评价大鼠神经功能,随后处死取脊髓,Western blot法检测LC3B、Beclin 1、Bcl-2蛋白的表达水平.结果 与Con组比较,I/R组脊髓LC3B、Beclin 1蛋白表达上调,Bcl-2蛋白表达下调,NDS评分升高(P＜0.05);与I/R组比较,Sevo组、3-MA组和3-MA+ Sevo组脊髓LC3B、Beclin 1蛋白表达下调,Bcl-2蛋白表达上调,NDS评分降低(P＜0.05);Sevo组、3-MA组和3-MA+ Sevo组各指标比较差异无统计学意义(P＞0.05).结论 七氟醚预处理可减轻大鼠脊髓缺血再灌注损伤,其机制可能与上调Bcl-2,抑制自噬溶酶体途径,减轻自噬有关.     

异氟醚对大鼠全脑缺血再灌注时海马ICAM-1 mRNA和外周血中性粒细胞表面CD11b/CD18表达的影响

目的 探讨异氟醚对大鼠全脑缺血再灌注时海马组织ICAM-1 mRNA和外周血中性粒细胞表面CD11b/CD18表达的影响.方法 Wistar大鼠63只,随机分为3组(n=21):假手术组(S组)、缺血再灌注组(I/R组)和异氟醚组(Iso组).采用四血管阻断法制备全脑缺血再灌注模型.Iso组在四血管阻断过程中及再灌注早期吸入1.4%异氟醚.于再灌注6、24、72 h时,采集外周静脉血,采用流式细胞仪测定中性粒细胞表面CD11b/CD18和CD18的表达;RT-PCR法测定海马组织细胞间粘附分子-1(ICAM-1)mRNA和核因子κB(NF-κB)mRNA的表达.结果 与S组比较,I/R组再灌注6 h时CD11b/CD18和CD11b表达上调,再灌注24、72 h时ICAM-1 mRNA表达上调,I/R组和Iso组再灌注24 h时NF-κB mRNA表达上调(P＜0.05或0.01);与I/R组比较,Iso组再灌注6 h时CD11b表达下调,再灌注24 h时ICAM-1 mRNA表达下调(P＜0.05).结论 异氟醚可减轻大鼠全脑缺血再灌注损伤,可能与其抑制海马ICAM-1 mRNA及外周血中性粒细胞表面CD11b/CD18的表达有关.     

ERK1/2激活参与乳化异氟醚后处理的脑保护作用

目的观察细胞外信号调节激酶1/2(ERK1/2)的激活在8%乳化异氟醚后处理对大鼠局灶性脑缺血-再灌注损伤中的作用。方法健康成年雄性SD大鼠48只,随机均分为六组:假手术组(S组)、缺血-再灌注组(IR组)、乳化异氟醚后处理组(EI组)、ERK抑制剂PD98059组(PD组)、乳化异氟醚后处理+PD98059组(EP组)、溶媒DMSO组(D组)。除S组外,均采用大脑中动脉阻闭2h,再灌注24h建立局灶性脑缺血-再灌注模型。缺血2h恢复再灌注即刻,EI组、EP组腹腔注射8%乳化异氟醚10.5ml/kg,其余各组注射生理盐水10.5ml/kg。PD组、EP组和D组于再灌注前30min侧脑室分别注入PD98059和DMSO。再灌注24h时进行神经功能缺陷评分(NDS评分),并观察组织形态学变化及细胞凋亡、p-ERK1/2阳性表达。结果与IR组相比,EI组NDS评分降低,凋亡细胞减少,磷酸化ERK1/2(p-ERK1/2)表达上调(P<0.05);与EI组相比,EP组NDS评分增高,凋亡细胞显著增加,p-ERK1/2表达下调(P<0.05)。结论 8%乳化异氟醚后处理通过激活ERK1/2信号通路对抗局灶性脑缺血-再灌注损伤。     

雷米芬太尼预处理对大鼠局灶性脑缺血-再灌注损伤的保护作用

目的观察雷米芬太尼预处理对大鼠局灶性脑缺血再灌注损伤的保护作用。方法23只雄性大鼠,随机分为两组。雷米芬太尼预处理(R)组(n=13)经股静脉注入雷米芬太尼(0.6μg·kg-1·min-1),每次5min输注,连续3次,中间间隔5min;盐水对照(C)组(n=10)经股静脉注入盐水,每次5min输注,连续3次,中间间隔5min;30min后,所有动物用右侧颈内动脉尼龙线线栓法致大脑中动脉阻闭120min,然后拔出尼龙线恢复再灌注。观察再灌注后24h神经功能障碍改变并评分。再灌注24h时处死动物,取大脑行2,3,5triphenyltetrazolium(TTC)染色以计算脑梗死容积百分比。结果缺血再灌注后动物均表现一定神经功能障碍,再灌注24h内C组神经功能障碍逐渐加重,R组则呈减轻趋势;再灌注24h时神经功能障碍评分(NDS)R组明显低于C组(P<0.05);再灌注24h时脑梗死容积百分比,R组明显小于C组(P<0.01)。结论雷米芬太尼预处理对大鼠局灶性脑缺血再灌注损伤可产生保护作用。     

右美托咪啶对异氟醚致新生鼠海马神经细胞凋亡的影响

【摘要】 目的 比较右美托咪啶(Dex)预处理给药和分次给药两种方法对异氟醚(Iso)致新生大鼠海马细胞凋亡的影响。方法 将出生后7天(postnatal day 7, P7)的SD大鼠随机分成6组:空气+盐水组(Air+NS组)、空气+Dex 25 μg·kg-1分次给药组(Air+Dex25×3组)、空气+Dex 75 μg·kg-1预处理组(Air+Dex75组)、异氟醚+盐水组(Iso+NS组)、异氟醚+ Dex 25μg·kg-1分次给药组(Iso+Dex25×3组)以及异氟醚+Dex 75μg·kg-1预处理组(Iso+Dex75组)。前3组吸入空气,后3组吸入0.75%异氟醚6 h。Air+NS组、Iso+NS组、Air+Dex75组和Iso+Dex75组在麻醉前20 min腹腔内注射生理盐水或75 μg·kg-1剂量的Dex;Air+Dex25×3组和Iso+Dex25×3组分别在麻醉前20 min,麻醉开始后2 h和4 h腹腔内重复注射25μg·kg-1剂量的Dex。麻醉结束后用原位末端标记(TUNEL)法检测海马神经细胞凋亡(n=4); 用Western blot检测海马激活型caspase-3蛋白表达变化(n=4)。 结果 异氟醚能诱导海马CA1区TUNEL阳性细胞数增加391.0 %(P<0.001);激活型caspase-3表达增加122.0%(P<0.001)。Iso +Dex25×3组和Iso+Dex75分别减少异氟醚诱导的TUNEL阳性细胞的增加为80.7%(P<0.001)和73.2%(P<0.001);两组均能完全抑制激活型caspase-3表达的增加(P<0.001);两组间无统计学差异(P>0.05)。结论 右美托咪啶预处理给药和分次给药都能通过抑制海马细胞凋亡来减轻异氟醚对新生大鼠的脑毒性作用,且两者的抗凋亡效果相似。     

诱导型一氧化氮合酶在异氟醚延迟相预处理心肌保护中的作用

目的研究诱导型一氧化氮合酶(iNOS)在异氟醚延迟相预处理心肌保护中的作用。方法新西兰白兔36只随机分成五组:异氟醚预处理组(n=9),异氟醚持续吸入2h;1400Wa组(n=6),给予选择性iNOS阻滞药1400W;1400Wb组(n=6),于缺血-再灌注前30min给予1400W;异氟醚 1400W组(n=6),给予异氟醚持续吸入2h,在缺血-再灌注前30min给予1400W;对照组(n=9),给予生理盐水。各组建立心肌局部缺血-再灌注模型。监测缺血-再灌注期间血流动力学参数,测定心肌梗死范围,检测iNOS基因水平表达和蛋白表达。结果异氟醚预处理组[(23.98±2.65)%]和对照组[(42.14±3.06)%]相比明显减少心肌缺血-再灌注后心肌梗死范围(P<0.01),异氟醚 1400W组[(42.12%±2.60)%]和异氟醚预处理组相比,1400W可以取消异氟醚的减少心肌梗死范围的作用(P<0.01)。iNOS在基因水平和蛋白表达水平均增加。结论异氟醚延迟相预处理具有抗心肌缺血-再灌注损伤的作用,而且这种作用是由iNOS所介导。     

异氟醚预处理对大鼠肝脏缺血再灌注损伤的影响

目的 探讨异氟醚预处理对大鼠肝脏缺血再灌注损伤的影响.方法 成年雄性SD大鼠24只,体重180～220 g,随机分为3组(n=8):假手术组(S组)吸人纯氧30 min,间隔30 min后仅开腹;肝脏缺血再灌注组(IR组)吸入纯氧30 min,间隔30 min后行肝脏缺血60 min,再灌注4 h;异氟醚预处理组(Iso组)吸入1.4%异氟醚30 min,间隔30 min后行肝脏缺血60 min,再灌注4 h.于再灌注4 h时处死大鼠,留取肝脏及腹主动脉血5ml.测定血清谷丙转氨酶(ALT)和谷草转氨酶(AST)浓度,血清及肝组织匀浆上清液中肿瘤坏死因子α(TNF-α)的浓度,肝组织髓过氧化物酶(MPO)、超氧化物歧化酶(SOD)活性及丙二醛(MDA)含量,观察肝组织病理学改变.结果 与S组比较,IR组、Iso组血清ALT、AST和TNF-α水平明显升高,肝组织TNF-α含量升高,肝组织MPO活性升高,MDA含量升高,SOD活性降低(P＜0.05或0.01),肝组织病理损伤明显;与IR组比较,Iso组血清ALT、AST和TNF-α水平降低,肝组织TNF-α含量降低,肝组织MPO活性降低,MDA含量降低,SOD活性升高(P＜0.05或0.01),肝组织病理损伤程度减轻.结论 1.4%异氟醚预处理可明显减轻大鼠肝脏缺血再灌注损伤,其机制可能与抑制TNF-α的释放、减少中性粒细胞在肝组织的浸润有关.     

Preconditioning with isoflurane produces dose-dependent neuroprotection via activation of adenosine triphosphate-regulated potassium channels after focal cerebral ischemia in rats

In this study, we determined whether repeated brief isoflurane (Iso) anesthesia induces ischemic tolerance to focal cerebral ischemia in a dose-response manner and whether the effect is dependent on adenosine triphosphate-regulated potassium channels. In Experiment 1, 40 rats were randomly assigned to 4 groups: control animals received 100% oxygen 1 h/d for 5 days, whereas the isoflurane (Iso)1, Iso2, and Iso3 groups received 0.75%, 1.5%, or 2.25% Iso in oxygen 1 h/d for 5 days. In Experiment 2, 36 rats were randomly assigned to 4 groups: controls received 100% oxygen 1 h/d for 5 days; animals in the Iso and I+G (Iso+glibenclamide) groups received 2% Iso in oxygen 1 h/d for 5 days, and the I+G group received glibenclamide (GLB) (5 mg/kg intraperitoneally) before each Iso pretreatment. Animals in the GLB group received GLB (5 mg/kg intraperitoneally) once a day for 5 days. Twenty-four hours after the last pretreatment, the right middle cerebral artery was occluded for 120 min. Neurologic deficit scores (NDS) and brain infarct volumes were evaluated at 24 h. The NDS and infarct volumes of Iso2 and Iso3 were less than those of the controls (P < 0.05). The infarct volume in Iso3 was smaller than in Iso2 (P < 0.05). The NDS and infarct volume in the Iso group were less than in the control and I+G groups (P < 0.05). There was no statistical difference among the control, I+G, and GLB groups. The study demonstrated that repeated Iso anesthesia induces ischemic tolerance in rats in a dose-response manner. GLB, an adenosine triphosphate-regulated potassium channel blocker, abolished the tolerance induced by Iso. IMPLICATIONS: Brief isoflurane anesthesia induces ischemic tolerance in the brain. The effect was found to be dose dependent in a rat focal cerebral ischemia model. Ischemic tolerance induced by isoflurane preconditioning is dependent on activation of adenosine triphosphate-regulated potassium channels.     

Isoflurane Produces Delayed Preconditioning against Spinal Cord Ischemic Injury via Release of Free Radicals in Rabbits

Background: Whether isoflurane preconditioning produces delayed neuroprotection in the spinal cord is unclear. The authors tested the hypothesis that isoflurane produces delayed preconditioning against spinal cord ischemic injury and, further, that the beneficial effect is dependent on free radicals.

Methods: In experiment 1, 63 rabbits were randomly assigned to seven groups (n = 9 each): Animals in the control group only underwent spinal cord ischemia without pretreatment; animals in the Iso24h, Iso48h, and Iso72h groups received 40 min of 1.0 minimum alveolar concentration isoflurane in 100% oxygen each day for 5 consecutive days, with the last pretreatment at 24, 48, and 72 h, respectively, before spinal cord ischemia; animals in the O224h, O248h, and O272h groups received 40 min of 100% oxygen each day for 5 consecutive days, with the last pretreatment at 24, 48, and 72 h, respectively, before spinal cord ischemia. In experiment 2, 48 rabbits were randomly assigned into four groups (n = 12 each): Animals in the O2 and Iso groups received 3 ml/kg saline intraperitoneally 1 h before each session of oxygen pretreatment and isoflurane pretreatment, respectively. In the DMTU+Iso and DMTU+O2 groups, 10% dimethylthiourea (DMTU, a potent free radical scavenger) dissolved in saline (3 ml/kg) was administered at the same time point. Twenty-four hours after the last pretreatment, animals were subjected to spinal cord ischemia. Spinal cord ischemia was induced by an infrarenal aorta clamping for 20 min. Forty-eight hours after reperfusion, neurologic function and histopathology of the spinal cord were examined.

Results: In experiment 1, the neurologic and histopathologic outcomes in the Iso24h and Iso48h groups were better than those in the control group (P < 0.005 for each comparison); the neurologic and histopathologic outcomes in the control group showed no significant differences in comparison with the O224h, O248h, O272h, and Iso72h groups (P > 0.05 for each comparison). In experiment 2, the neurologic and histopathologic outcomes in the Iso group were better than those in the DMTU+Iso, O2, and DMTU+O2 groups (P < 0.01 for each comparison); there were no significant differences in the neurologic and histopathologic outcomes among the DMTU+Iso, O2, and DMTU+O2 groups (P > 0.05 for each comparison).     

Isoflurane produces delayed preconditioning against spinal cord ischemic injury via release of free radicals in rabbits

BACKGROUND: Whether isoflurane preconditioning produces delayed neuroprotection in the spinal cord is unclear. The authors tested the hypothesis that isoflurane produces delayed preconditioning against spinal cord ischemic injury and, further, that the beneficial effect is dependent on free radicals. METHODS: In experiment 1, 63 rabbits were randomly assigned to seven groups (n = 9 each): Animals in the control group only underwent spinal cord ischemia without pretreatment; animals in the Iso24h, Iso48h, and Iso72h groups received 40 min of 1.0 minimum alveolar concentration isoflurane in 100% oxygen each day for 5 consecutive days, with the last pretreatment at 24, 48, and 72 h, respectively, before spinal cord ischemia; animals in the O2 24h, O2 48h, and O2 72h groups received 40 min of 100% oxygen each day for 5 consecutive days, with the last pretreatment at 24, 48, and 72 h, respectively, before spinal cord ischemia. In experiment 2, 48 rabbits were randomly assigned into four groups (n = 12 each): Animals in the O2 and Iso groups received 3 ml/kg saline intraperitoneally 1 h before each session of oxygen pretreatment and isoflurane pretreatment, respectively. In the DMTU+Iso and DMTU+O2 groups, 10% dimethylthiourea (DMTU, a potent free radical scavenger) dissolved in saline (3 ml/kg) was administered at the same time point. Twenty-four hours after the last pretreatment, animals were subjected to spinal cord ischemia. Spinal cord ischemia was induced by an infrarenal aorta clamping for 20 min. Forty-eight hours after reperfusion, neurologic function and histopathology of the spinal cord were examined. RESULTS: In experiment 1, the neurologic and histopathologic outcomes in the Iso24h and Iso48h groups were better than those in the control group (P < 0.005 for each comparison); the neurologic and histopathologic outcomes in the control group showed no significant differences in comparison with the O2 24h, O2 48h, O2 72h, and Iso72h groups (P > 0.05 for each comparison). In experiment 2, the neurologic and histopathologic outcomes in the Iso group were better than those in the DMTU+Iso, O2, and DMTU+O2 groups (P < 0.01 for each comparison); there were no significant differences in the neurologic and histopathologic outcomes among the DMTU+Iso, O2, and DMTU+O2 groups (P > 0.05 for each comparison). CONCLUSIONS: Isoflurane produces delayed preconditioning against spinal cord ischemic injury, and the beneficial effect may be dependent on the release of free radicals.     

异氟醚预处理对大鼠局灶性脑缺血再灌注时TLR4和MyD88表达的影响

目的 评价异氟醚预处理对大鼠局灶性脑缺血再灌注时Toll样受体4(TLR4)和髓样分化因子88(MyD88)表达的影响.方法 雄性成年SD大鼠54只,体重250～300 g,随机分为3组(n=18):假手术组(S组)仅分离血管,不留置线栓;脑缺血再灌注组(IR组)采用线栓法制备大鼠局灶性脑缺血再灌注模型,缺血2 h,再灌注24 h;异氟醚预处理(IP组)吸入2%异氟醚,1h/d,连续5 d,处理结束后24 h时制备大鼠局灶性脑缺血再灌注模型.再灌注24 h时进行神经功能缺陷评分,然后每组处死3只大鼠,测定脑梗死体积.分别于再灌注24、48和72 h时,处死5只大鼠,取右侧大脑缺血部位额叶皮质,采用Western blot法测定TLR4、MyD88和NF-κB的表达水平.结果 与S组比较,IR组和IP组神经功能缺陷评分升高,脑梗死体积增大,IR组TLR4、MyD88和NF-κB的表达均上调,IP组MyD88和NF-κB的表达上调(P＜0.05);与IR组比较,IP组神经功能缺陷评分降低,脑梗死体积减小,TLR4、MyD88和NF-κB的表达均下调(P＜0.05).结论 异氟烷预处理可通过抑制脑组织TLR4和MyD88的表达,减轻炎性反应,从而减轻大鼠局灶性脑缺血再灌注损伤.     

异氟醚预处理对大脑中动脉闭塞大鼠胶质细胞中Toll样受体4表达的影响

目的观察异氟醚预处理对大脑中动脉闭塞(MCAO)模型大鼠胶质细胞中Toll样受体4(TLR4)表达的影响。方法雄性SD大鼠48只,体重250～300g,随机均分为三组:假手术组(S组)、MCAO模型组(M组)、异氟醚预处理组(I组)。2h后进行再灌注,再灌注24h后进行神经功能评分,检测脑梗死容积,分别测定每个视野内TLR4与星形胶质细胞标记物(GFAP)共存阳性细胞数和TLR4与小胶质细胞标记物(OX42)共存阳性细胞数。结果与M组相比,I组神经功能评分降低,脑梗死容积减少,GFAP和OX42阳性细胞数均减少(P<0.05)。结论异氟醚预处理具有脑保护作用,抑制TLR4的表达及胶质细胞的活化可能是其作用机制之一。     

阿片受体在异氟醚延迟预处理减轻兔心肌缺血再灌注损伤中的作用

目的 探讨阿片受体在异氟醚延迟预处理减轻兔心肌缺血再灌注损伤中的作用.方法 健康雄性新西兰大白兔40只,体重2.0～2.5 kg,采用结扎左冠状动脉前降支40 min,再灌注120 min的方法制备心肌缺血再灌注损伤模型,随机分为4组(n=10):假手术组(S组)吸入纯氧2 h,24 h后仅动脉下穿线不结扎;心肌缺血再灌注组(IR组)吸入纯氧2 h,24 h后行心肌缺血再灌注;异氟醚延迟预处理组(I组)吸人2%异氟醚2 h,24 h后行心肌缺血再灌注;阿片受体阻断剂+异氟醚延迟预处理组(N组)静脉注射纳洛酮6 mg/kg后10 min,吸入2%异氟醚2 h,24 h后行心肌缺血再灌注.于再灌注120 min时取心脏,计算心肌缺血面积和梗死面积,测定磷酸化p38MAPK蛋白表达水平,观察心肌细胞超微结构.结果 S组心肌细胞完整,排列整齐,线粒体形态正常,糖原丰富;IR组和N组心肌细胞水肿,心肌纤维排列紊乱,线粒体、内质网膜水肿,空泡化;I组心肌细胞水肿程度减轻,心肌纤维排列较完整,线粒体轻度水肿.与IR组比较,I组心肌梗死面积减小,磷酸化p38MAPK蛋白表达下调(P<0.05),N组上述指标差异无统计学意义(P>0.05).结论 阿片受体参与异氟醚延迟预处理减轻兔心肌缺血再灌注损伤.     

乳化异氟醚预处理对大鼠局灶性脑缺血再灌注时脑组织突触后致密物质95活化的影响

目的 探讨乳化异氟醚预处理对大鼠局灶性脑缺血再灌注时脑组织突触后致密物质95(PSD95)活化的影响.方法 雄性清洁级SD大鼠32只,体重280 ～ 300 g,采用随机数字表法,将大鼠随机分为4组(n=8):假手术组(S组)、缺血再灌注组(I/R组)、乳化异氟醚组(EI组)和脂肪乳剂组(LE组).采用大脑中动脉阻塞法制备局灶性脑缺血再灌注模型.EI组和LE组分别腹腔注射8％乳化异氟醚10.5 ml/mg或30％脂肪乳10.5 ml/mg,24h后制备模型.再灌注6h时行神经功能缺陷评分,随机取4只大鼠,处死后取缺血侧海马和皮层组织,采用Western blot法检测磷酸化的PSD95( pPSD95)的表达水平.再灌注24 h时,随机取4只大鼠,处死后取脑组织,计算脑梗死体积百分比.结果 S组未见神经功能缺陷和脑梗死发生.与S组比较,I/R组、EI组和LE组神经功能缺陷评分、脑梗死体积百分比、海马和皮质pPSD95表达水平升高(P＜0.01);与I/R组比较,EI组神经功能缺陷评分、脑梗死体积百分比、海马和皮质pPSD95表达水平降低(P＜0.05),LE组差异无统计学意义(P＞0.05).结论乳化异氟醚可通过抑制脑组织PSD95的活化,减轻大鼠局灶性脑缺血再灌注损伤.     

Neuroprotective effect of low-dose lidocaine in a rat model of transient focal cerebral ischemia

BACKGROUND: A low concentration of lidocaine (10 microM) has been shown to reduce anoxic damage in vitro. The current study examined the effect of low-dose lidocaine on infarct size in rats when administered before transient focal cerebral isehemia. METHODS: Male Wistar rats (weight, 280-340 g) were anesthetized with isoflurane, intubated, and mechanically ventilated. After surgical preparation, animals were assigned to lidocaine 2-day (n = 10), vehicle 2-day (n 12), lidocaine 7-day (n = 13), and vehicle 7-day (n = 14) groups. A 1.5-mg/kg bolus dose of ildocaine was injected intravenously 30 mm before isehemia in the lidocaine 2-day and 7-day groups. Thereafter, an infusion was initiated at a rate of 2 mg x kg(-1) x h(-1) until 60 min of reperfusion after isehemia. Rats were subjected to 90 min of focal cerebral isehemia using the intraluminal suture method. Infarct size was determined by image analysis of 2,3,5-triphenyltetrazolium chloride-stained sections at 48 h or hematoxylin and eosin-stained sections 7 days after reperfusion. Neurologic outcome and body weight loss were also evaluated. RESULTS: The infarct size was significantly smaller in the lidocaine 2-day group (185.0+/-43.7 mm3) than in the vehicle 2-day group (261.3+/-45.8 mm3, P < 0.01). The reduction in the size of the infarct in the lidocaine 7-day group (130.4+/-62.9 mm3) was also significant compared with the vehicle 7-day group (216.6+/-73.6 mm3, P < 0.01). After 7 days of reperfusion, the rats in the lidocaine group demonstrated better neurologic outcomes and less weight loss. CONCLUSIONS: The current study demonstrated that a clinical anriarrhythmic dose of lidocaine, when given before and during transient focal cerebral isehemia, significantly reduced infaret size, improved neurologic outcome, and inhibited postisehemic weight loss.     

乳化异氟烷预处理对大鼠局灶性脑缺血再灌注损伤的影响

目的 评价8%乳化异氟烷预处理对大鼠局灶性脑缺血再灌注损伤的影响.方法 健康雄性成年SD大鼠56只,体重250～280 g,随机分为4组(n=14),假手术组(S组)仅分离血管,不留置线栓;脑缺血再灌注组(IR组)、乳化异氟烷预处理组(EIP组)和脂肪乳剂组预处理(FIP组)分别腹腔注射生理盐水、8%乳化异氟烷或30%脂肪乳剂7.5 ml/kg,24 h后制备局灶性脑缺血再灌注模型.于再灌注24 h各组取8只大鼠,进行神经功能缺陷评分,然后处死大鼠,取脑组织,测定脑梗死体积;各组处死6只大鼠,取脑组织,检测细胞凋亡情况,计算细胞凋亡率,并测定Bcl-2、Bax、caspase-3和Cyt C的蛋白表达水平.结果 与S组比较,IR组、EIP组和FIP组神经功能缺陷评分和细胞凋亡率升高,脑组织Bcl-2、Bax、caspase-3和Cyt C的蛋白表达上调(P＜0.01);与IR组和FIP组比较,EIP组神经功能缺陷评分和细胞凋亡率降低,脑梗死体积减小,脑组织Bcl-2蛋白表达上调,Bax、caspase-3和Cyt C 的蛋白表达下调(P＜0.05);IR组和FIP组各指标比较差异无统计学意义(P＞0.05).结论 8%乳化异氟烷预处理可减轻大鼠脑缺血再灌注损伤,其机制可能与上调Bcl-2蛋白表达,下调Bax蛋白表达,减少线粒体释放Cyt C,降低caspase-3活化,抑制神经元凋亡有关.     

Effect of isoflurane on neuronal apoptosis in rats subjected to focal cerebral ischemia

Although isoflurane can reduce ischemic neuronal injury after short postischemic recovery intervals, this neuroprotective efficacy is not sustained. Neuronal apoptosis can contribute to the gradual increase in infarct size after ischemia. This suggests that isoflurane, although capable of reducing early neuronal death, may not inhibit ischemia-induced apoptosis. We investigated the effects of isoflurane on markers of apoptosis in rats subjected to focal ischemia. Fasted Wistar-Kyoto rats were anesthetized with isoflurane and randomly allocated to awake (n = 40) or isoflurane (n = 40) groups. Animals in both groups were subjected to focal ischemia by filament occlusion of the middle cerebral artery for 70 min. Pericranial temperature was servo-controlled at 37 degrees C +/- 0.2 degrees C throughout the experiment. In the awake group, isoflurane was discontinued and the animals were allowed to awaken. In the isoflurane group, isoflurane anesthesia was maintained at 1.5 MAC (minimum alveolar anesthetic concentration). Animals were killed 7 h, 1 day, 4 days, or 7 days after reperfusion (n = 10/group/time point). The area of cerebral infarction was measured by image analysis in a hematoxylin and eosin stained section. In three adjacent sections, apoptotic neurons were identified by TUNEL staining and immunostaining for active caspase-9 and caspase-3. Infarct size was smaller in the isoflurane group than the awake group 7 h, 1 day, and 4 days after reperfusion (P < 0.05). However, this difference was absent 7 days after reperfusion. The number of apoptotic (TUNEL, caspase-3, and caspase-9 positive) cells 1 day after ischemia was significantly more in the awake versus isoflurane group. After a recovery period of 4 or 7 days, the number of apoptotic cells in the isoflurane group was more than in the awake group. After 7 days, the number of caspase-3 and -9 positive neurons was more in the isoflurane group (P < 0.05). The data indicate that isoflurane delays but does not prevent the development of cerebral infarction caused by ischemia. Isoflurane reduced the development of apoptosis early after ischemia but did not prevent it at later stages of postischemic recovery. IMPLICATIONS: The effect of isoflurane on neuronal apoptosis was investigated in rats subjected to focal cerebral ischemia. In isoflurane-anesthetized animals, ischemia-induced apoptosis occurred during the later stages of postischemic recovery. Isoflurane did not inhibit postischemic neuronal apoptosis.