不同剂量异氟醚对中年小鼠认知功能及海马MBP和pNF-H表达的影响

目的:探讨异氟醚对中年小鼠认知功能及海马髓磷脂碱性蛋白(MBP, myelin basic protein)和磷酸化神经丝重亚单位(pNF-H,phosphorylated neurofilament heavy chain)表达的影响。方法:给予中年小鼠不同浓度的异氟醚处理,实验分为对照组和异氟醚处理组(0.5ISO,1.0ISO,1.5ISO),其中异氟醚组小鼠细胞分别给予0.5 MAC,1.0 MAC和1.5 MAC三个浓度的异氟醚处理4小时,对照组给予O_2处理4小时,随后通过水迷宫测试检测其学习记忆能力变化,通过免疫荧光检测海马形态结构及髓鞘相关蛋白MBP和pNF-H表达变化。结果:与对照组相比,(1)类临床浓度的异氟醚处理不影响中年小鼠的自发运动能力(总运动距离:sham:7275.17±1732.58; 0.5ISO:8057.58±1732.58; 1.0ISO:7540.98±1401.61; 1.5ISO:8243.79±1257.65;运动速度:sham:116.75±22.35; 0.5ISO:135.45±32.84; 1.0ISO:130.16±21.38; 1.5ISO:142.31±20.58),但1.0 MAC和1.5 MAC的异氟醚处理明显降低了中年小鼠在水迷宫目标象限的活动时间百分比(sham:58.62±13.70; 0.5ISO:48.92±7.22; 1.0ISO:31.23±13.16; 1.5ISO:30.29±15.76)(P 0.05),且高浓度异氟醚作用强于低浓度异氟醚;(2) 1.0 MAC和1.5 MAC的异氟醚处理明显下调了海马的MBP和p NF-H表达(MBP:sham:60.48±8.20; 0.5ISO:56.69±7.86; 1.0ISO:40.15±4.50; 1.5ISO:31.66±5.46; pNF-H:sham:62.23±9.45; 0.5ISO:55.47±6.98; 1.0ISO:40.16±6.97; 1.5ISO:30.94±5.89)(P 0.05),造成了小鼠海马髓鞘结构损伤,且高浓度损伤强于低浓度。结论:异氟醚可能通过下调中年小鼠海马MBP和pNF-H表达,破坏海马髓鞘完整性而损伤小鼠的学习认知能力。     

异氟烷对小鼠神经干细胞BDNF/Caspase3 及Notch信号相关基因表达的影响

目的:探讨异氟烷对小鼠神经干细胞的BDNF、Caspase3及Notch信号相关基因表达的影响。方法:给予体外培养的新生小鼠海马神经干细胞不同浓度异氟烷处理,实验分为对照组和异氟烷处理组(ISO1.0,ISO1.5),其中异氟烷组细胞分别给予1.0MAC和1.5 MAC两个浓度的异氟烷处理2小时,对照组给予O_2处理2小时,随后置于培养箱正常培养24小时后收集细胞,提取细胞RNA检测BDNF,Caspase3及Notch相关基因(Notch2、Notch 3和Hes5)的m RNA水平变化。结果:与对照组相比,(1)异氟烷组小鼠神经干细胞的功能基因BDNF m RNA水平下调,凋亡相关基因Caspase3的m RNA水平上调;(2)异氟烷组神经干细胞的Notch2和Notch3受体m RNA表达下调,Notch信号通路靶基因Hes5的m RNA水平也明显下调;(3)异氟烷对神经干细胞的作用具有剂量依赖性,浓度越高对神经干细胞BDNF、Caspase3及Notch信号相关基因表达的影响越大。结论:异氟烷可能通过抑制小鼠神经干细胞的Notch信号通路,下调BDNF的m RNA表达,上调Caspase3的m RNA水平,影响神经干细胞的正常功能。     

异氟醚对小鼠神经干细胞活力及内大麻素系统相关基因表达的影响

目的:探讨异氟醚对小鼠神经干细胞活力及内大麻素系统相关基因表达的影响。方法:给予体外培养的小鼠海马神经干细胞不同浓度异氟醚处理,实验分为对照组和异氟醚处理组(0.5ISO,1.0ISO),其中异氟醚组细胞分别给予0.5 MAC和1.0 MAC两个浓度的异氟醚处理2小时,对照组给予O_2处理2小时,随后检测细胞活力并提取细胞RNA检测其内源性大麻素受体1(Cannabinoid receptor1,CB1)、脂肪酰胺水解酶(Fatty acid amide hydrolase,FAAH)、单酰甘油脂肪酶(Monoacylglycerol lipase,MAGL)及二酰基甘油脂肪酶(Diacylglycerol lipase alpha,DAGLα)的mRNA表达的变化。结果:与对照组相比,(1)异氟醚处理明显抑制了体外培养神经干细胞的活力,且高浓度异氟醚抑制作用强于低浓度异氟醚;(2)异氟醚上调神经干细胞的内大麻素受体CB1 mRNA水平,且高浓度异氟醚作用强于低浓度异氟醚;(3)异氟醚促进神经干细胞FAAH和MAGL的mRNA表达而抑制DAGLα的mRNA表达,且高浓度异氟醚作用强于低浓度异氟醚。结论:异氟醚可能通过影响小鼠神经干细胞的内大麻素系统影响神经干细胞的活力。     

天麻素对镉诱导的星形胶质细胞损伤的保护效应

目的:探讨氯化镉(CdCl_2)和天麻素(GAS)对小鼠星形胶质细胞活力及神经营养因子GDNF和抗氧化基因Nrf2,HO-1,SOD-1表达的影响。方法:首先,给予体外培养的小鼠星形胶质细胞不同浓度的CdCl_2(Con,2.5μM,5μM,10μM,20μM)处理24 h或48 h,随后检测细胞活力筛选出造成星形胶质细胞损伤的CdCl_2浓度和时间。然后使用上述筛选的CdCl_2作用浓度(5μM)构建星形胶质细胞损伤的同时再给予不同浓度的天麻素(0,20μg/m L,30μg/m L,40μg/m L, 50μg/m L)处理24 h或48 h,随后检测细胞活力并提取细胞RNA检测其caspase3,GDNF(胶质源性神经营养因子Glial cell-derived neurotrophic factor,GDNF)和Nrf2(Nuclear factor erythroid2-related factor2),HO-1(Heme oxygenase 1),SOD-1(superoxide dismutase 1)等抗氧化基因的m RNA表达的变化。结果:(1) 2.5μM CdCl_2处理24 h后星形胶质细胞活力已经有明显下降(P0.05),5μM CdCl_2处理24 h后,星形胶质细胞活力显著下降(P0.01);(2) CdCl_2浓度越大,细胞损伤严重;(3)一定浓度的天麻素处理可以缓解CdCl_2造成的星形胶质损伤,恢复其细胞活力,下调caspase3 m RNA水平;(4) CdCl_2下调了星形胶质细胞的GDNF, Nrf2, HO-1和SOD-1的m RNA水平,天麻素可以抑制Cd Cl_2对上述基因的m RNA水平的调节作用,且浓度越高调节作用越强。结论:天麻素可能通过调节小鼠星形胶质细胞的GDNF, Nrf2, HO-1和SOD-1基因表达缓解CdCl_2导致的细胞损伤。     

海马Sirt1在高压氧预处理改善异氟醚诱导老龄小鼠认知功能障碍中的作用

摘要 目的：通过shRNA抑制沉默信息调节因子1（sirtuin 1,Sirt1）基因表达,研究Sirt1在高压氧预处理改善异氟醚（isoflurane,ISO）诱导小鼠认知功能障碍中的作用及其对小鼠海马BDNF、GDNF基因表达的影响。方法： 将64只C57雄性小鼠随机分为假手术组（Sham组）、高压氧组（HBO组）、异氟醚组（ISO组）、高压氧预处理+异氟醚组（HBO + ISO组）;以及对照组（NS组）、Sirt1抑制组（sh-Sirt1组）、对照+高压氧预处理组（NS + HBO组）和Sirt1抑制+高压氧预处理组（sh-Sirt1 + HBO组）,每组8只。经慢病毒转染以及ISO末次暴露24小时后进行认知功能测试（Morris水迷宫测试）,随后处死小鼠,利用实时荧光定量聚合酶链反应（RT-qPCR）检测海马BDNF和GDNF的mRNA表达情况。结果：（1）异氟醚可以导致明显的认知功能障碍,与Sham组相比,ISO组靶象限探索时间百分比显著减低（P<0.01）,ISO组小鼠海马BDNF和GDNF mRNA表达水平显著下降（P<0.01）。（2）高压氧预处理可以改善POCD小鼠的认知功能障碍,ISO + HBO组靶象限探索时间百分比显著高于ISO组（P<0.05）,ISO + HBO组小鼠海马BDNF（P<0.05）和GDNF（P<0.01）mRNA表达水平显著升高。（3）高压氧预处理可以显著增加POCD小鼠海马BDNF（P<0.01）和GDNF（P<0.05）mRNA表达水平,慢病毒介导shRNA靶向下调Sirt1可以逆转高压氧预处理对POCD小鼠海马BDNF（P<0.05）和GDNF（P<0.01）mRNA表达水平的改变。结论：高压氧预处理是治疗POCD的有效方法,Sirt1可能是POCD治疗的潜在分子靶点。     

活化星形胶质细胞NGF、IL-6表达的时间特性

目的:研究星形胶质细胞活化后神经生长因子(nerve growth factor,NGF)、白细胞介素-6(interleukin-6,IL-6)表达的时间规律性,探讨星形胶质细胞活化后启动保护性机制与损伤性机制的时间特性.方法:体外分离培养星形胶质细胞,分为对照组、活化组、抑制组.通过光学显微镜及免疫荧光化学观察各组细胞的形态变化;应用半定量RT-PCR方法分析各组细胞间胶原纤维酸性蛋白(glial fibrillary acidic protein,GFAP)mRNA及NGF mRNA、IL-6 mRNA表达变化;用ELISA法检测各组细胞上清液中不同时间点(6h,24h,48h,72h)NGF、IL-6的含量.结果:活化组与对照组比较,细胞胞体变大,GFAP荧光增强;RT-PCR示GFAP mRNA、NGF mRNA、IL-6 mRNA表达均明显增高,与对照组比较差异有显著性(P＜0.01);ELISA法检测示星形胶质细胞活化后NGF分泌量在活化后24小时达到高峰,与对照组比较差异有显著性(P＜0.01);活化后48小时IL-6的含量达到高峰,与对照组比较差异有显著性(P＜0.01);应用抑制剂Genistein干预后,与活化组相比,抑制组细胞胞体变小,星形胶质细胞活化被抑制,GFAP mRNA表达下降,NGF mRNA、IL-6 mMRA表达亦下降,与活化组比较差异有显著性(P＜0.01).结论:星形胶质细胞活化后NGF、IL-6表达均上调,但NGF表达时间早于IL-6表达时间,表明在星形胶质细胞活化的早期,可能其神经保护作用占主导,而后期其神经毒性作用逐渐明显;Genistein能抑制星形胶质细胞活化,使NGF、IL-6表达下调.     

七氟烷对培养的小鼠小胶质细胞炎症因子表达的影响（英文）

目的:探讨七氟烷对培养的小鼠小胶质细胞中炎症因子表达的影响。方法:取新生(2~3天)C57BL/6小鼠,分离小胶质细胞,将其随机分为4组(n=10):对照组(Control);七氟烷组(Sevoflurane);NF-κB抑制剂组(PDTC);NF-κB抑制剂+七氟烷组(PDTC+Sevoflurane)。用Drager麻醉机向Sevoflurane组PDTC+Sevoflurane组培养的小胶质细胞盒内释放21%O2,5%CO2,4.1%七氟烷的气体,用气体分析仪持续监测各组的浓度。应用Iba-1的免疫荧光染色法对小鼠小胶质细胞进行纯度鉴定。分别在于给七氟烷后2 h、4 h和6 h时采用免疫印迹分析技术检测两组小胶质细胞IL-6和TNF-α的表达水平和NF-κB的活性。PDTC+Sevoflurane组在给七氟烷前一小时给予PDTC,采用ELISA技术和免疫印迹分析技术检测各组小胶质细胞IL-6和TNF-α的浓度和NF-κB的表达。结果:免疫印迹显示七氟烷组细胞中IL-6、TNF-α水平和NF-κB的激活水平升高;PDTC降低了七氟烷作用后核内NF-κB的表达,减弱了IL-6和TNF-α水平的升高作用。结论:七氟烷可通过激活NF-κB信号通路,进一步激活培养的小鼠小胶质细胞中炎症因子的表达。     

Nrf3通路参与星形胶质细胞对抗鱼藤酮毒性的保护作用

目的：寻找星形胶质细胞在对抗由鱼藤酮导致的氧化应激中发挥保护作用的相关分子并探讨其作用机制。 方法：小鼠多巴胺能MN9D细胞分别在星形胶质细胞条件培养液（ACM）与星形胶质细胞用新鲜培养基中培养24小时后加入鱼藤酮作用48小时。细胞计数,评价星形胶质细胞条件培养液对MN9D细胞的保护作用。利用基因芯片技术寻找MN9D细胞在ACM处理后发生表达上调或下调基因,并对这些基因进行分析,找出有意义基因。结果： 在不同作用时间和鱼藤酮浓度梯度下,经过ACM处理的MN9D细胞活性显著高于在普通培养基中培养的细胞。初步得到104个差异表达基因,其中62个表达上调基因,42个表达下调基因。这些基因主要与凋亡、肿瘤、细胞周期、代谢、信号转导、转录调节、翻译调节和传递蛋白等相关。对其中的Atp5a1,Nrf3基因进行分析,发现Nrf3通路参与了ACM的保护作用。结论： ACM能保护MN9D细胞抵抗鱼藤酮所致的细胞毒性, Atp5a1,Nrf3,GCL,NQO1等基因经ACM处理后发生差异表达,可能是星形胶质细胞保护作用的部分下游信号通路。     

七氟烷对培养的小鼠小胶质细胞炎症因子表达的影响

目的：探讨七氟烷对培养的小鼠小胶质细胞中炎症因子表达的影响。方法：取新生（2~3 天）C57BL/6小鼠,分离小胶质细胞, 将其随机分为4 组（n=10）：对照组（Control）;七氟烷组（Sevoflurane）;NF-资B抑制剂组（PDTC）;NF-kB 抑制剂+七氟烷组 （PDTC+Sevoflurane）。用Drager 麻醉机向Sevoflurane 组PDTC+Sevoflurane 组培养的小胶质细胞盒内释放21%O2,5%CO2,4.1% 七氟烷的气体,用气体分析仪持续监测各组的浓度。应用Iba-1 的免疫荧光染色法对小鼠小胶质细胞进行纯度鉴定。分别在于给 七氟烷后2 h、4 h 和6 h 时采用免疫印迹分析技术检测两组小胶质细胞IL-6 和TNF-alpha的表达水平和NF-kB 的活性。 PDTC+Sevoflurane 组在给七氟烷前一小时给予PDTC,采用ELISA 技术和免疫印迹分析技术检测各组小胶质细胞IL-6 和 TNF-alpha的浓度和NF-kB 的表达。结果：免疫印迹显示七氟烷组细胞中IL-6、TNF-alpha水平和NF- kB 的激活水平升高;PDTC降低了 七氟烷作用后核内NF-kB 的表达,减弱了IL-6和TNF-alpha水平的升高作用。结论：七氟烷可通过激活NF-kB信号通路,进一步激 活培养的小鼠小胶质细胞中炎症因子的表达。     

C1型尼曼-匹克氏症小鼠嗅球胶质细胞的活性变化

本文观察Npc1基因突变对于小鼠嗅球神经胶质细胞活性的影响,探讨C1型尼曼-匹克氏症的病理机制。提取鼠尾基因组DNA,采用PCR检测基因型;采用免疫荧光组织化学染色观察出生后30 d的小鼠嗅球中小胶质细胞和星形胶质细胞的活性反应;采用免疫印迹方法检测嗅球中Neu N、神经丝蛋白(neurofilament,NF)、双皮质素(Doublecortin,DCX)、CD68和GFAP的蛋白表达情况。结果显示,Npc1基因突变导致小鼠嗅球中CD68和GFAP蛋白表达显著上调,小胶质细胞和星形胶质细胞的活性明显增强;磷酸化NF的表达也明显增加,而DCX的表达量显著下调。以上结果提示,Npc1基因突变在早期能够引起小鼠嗅球发生一些变化。     

Relationship of feline bispectral index to multiples of isoflurane minimum alveolar concentration

The study reported here was done to determine the relationship between bispectral index (BIS) values and minimum alveolar concentration (MAC) multiples of isoflurane in cats. Isoflurane MAC was determined using the tail-clamp method in eight domestic cats. Ten days later, the cats were anesthetized a second time with isoflurane at each of five MAC multiples administered in random order. Ventilation was controlled and, after a 20-min equilibration period at each MAC multiple of isoflurane, BIS data were collected for 5 min and the median BIS value calculated. Data from each isoflurane MAC multiple were compared using analysis of variance for repeated measures, and statistical significance was set at P < 0.05. The MAC of isoflurane (mean +/- 1 standard deviation) was 1.8% +/- 0.2%. BIS values at 0.5 MAC could not be recorded due to spontaneous movement in all eight cats. BIS values at 2.0 MAC were confounded by burst suppression in seven of the eight cats. Over the range of 0.8 to 1.5 MAC, BIS values decreased significantly with increasing end-tidal isoflurane concentrations. Mean (+/- 1 standard deviation) BIS measurements were 32 +/- 3 at 0.8 MAC, 20 +/- 4 at 1.0 MAC, and 5 +/- 3 at 1.5 MAC. Therefore, BIS values are inversely and linearly related to end-tidal isoflurane concentrations in anesthetized cats. However, the consistently low BIS values recorded in this study suggest that clinical BIS endpoints used to titrate anesthetic agents in humans may not be applicable to cats.     

Changes in minimal alveolar concentration of isoflurane following treatment with medetomidine and tiletamine/zolazepam, epidural morphine or systemic buprenorphine in pigs

The aim of this study was to determine the changes in minimal alveolar concentration (MAC) of isoflurane after treatment with medetomidine and tiletamine/zolazepam (MTZ), epidural morphine or systemic buprenorphine in 11 healthy crossbred pigs. The first part of this study was to measure the baseline values in pigs induced with isoflurane (5%) by face mask and maintained with isoflurane in air and oxygen for 2 h (ISO). Baseline isoflurane MAC was determined using mechanical stimulation. Thereafter, each pig was randomly chosen for a crossover test in which the same animal received three different treatments with at least one week in between treatments. The three treatments were as follows: induction of anaesthesia with medetomidine (0.05 mg kg(-1)) and tiletamine/zolazepam (2.5 mg kg(-1) each) given intramuscularly (MTZ); MTZ followed by epidural morphine (0.1 mg kg(-1); MTZ/M); and MTZ followed by intramuscular buprenorphine (0.1 mg kg(-1); MTZ/B). All pigs were maintained with isoflurane in oxygen and air for 2 h and their lungs were mechanically ventilated. The end-tidal isoflurane concentration, respiratory rate, inspiratory and expiratory O2 and CO2 concentrations, heart rate (HR) and arterial blood pressure were recorded every 10 min. Arterial blood gases were analysed every 20 min. Among the treatment groups, differences in isoflurane MAC were tested using GLM and Tukey's method for further comparison; P < 0.05 was adopted as significant. Isoflurane MAC was 1.9 +/- 0.3%. MTZ reduced isoflurane MAC to 0.6 +/- 0.1%. Additional morphine or buprenorphine reduced the MTZ isoflurane MAC further to 0.4 +/- 0.2 and 0.3 +/- 0.1%, respectively. During MTZ, MTZ/M and MTZ/B mean arterial blood pressure was higher and the alveolar-arterial oxygen tension difference was lower compared with ISO. In conclusion, induction of anaesthesia with MTZ reduced the isoflurane MAC in pigs by 68%. Additional epidural morphine or systemic buprenorphine decreased MTZ isoflurane MAC by 33 and 50%, respectively.     

异氟烷对化疗性大鼠异食癖恶心呕吐模型神经功能及呕吐相关神经递质的影响

摘要 目的：研究异氟烷预处理对化疗性大鼠异食癖恶心呕吐模型神经功能及呕吐相关神经递质的影响。方法：选用SD大鼠作为研究对象,腹腔注射顺铂以建立化疗性大鼠异食癖恶心呕吐模型（Model组）,腹腔注射等量生理研究作为对照组（Control）,在腹腔注射顺铂前1 h和12 h吸入异氟烷预处理作为异氟烷治疗组（Isoflurane）。记录腹腔注射顺铂0~12 h和12~24 h内各组大鼠摄入高岭土量;在腹腔注射顺铂0 h、12 h和24 h后,通过神经功能缺损评分法对各组大鼠神经功能进行评分;并在腹腔注射顺铂24 h后处死大鼠,收集大鼠回肠和延髓组织以检测5-羟色胺(5-Hydroxytryptamine,5-HT)、5-羟基-吲哚乙酸（5-hydroxy-indole acetic acid,5-HIAA）、色氨酸羟化酶（Tryptophan hydroxylase,TPH）以及单胺氧化酶（Monoamine oxidase,MAOA）含量。结果：与Control组相比,Model组和Isoflurane组大鼠在腹腔注射顺铂0~12 h,12~24 h以及0~24 h内摄入的高岭土量均显著升高（P<0.05）,并且Isoflurane组大鼠均显著Model组。三组大鼠在腹腔注射顺铂0 h、12 h和24 h后,神经功能评分均无显著差异（P>0.05）。与Control组大鼠相比,Model组和Isoflurane组大鼠在腹腔注射顺铂24 h后回肠/延髓组织内5-HT和TPH含量均显著升高,并且Isoflurane组大鼠显著低于Model组大鼠（P<0.05）;与Control组相比,Model组大鼠回肠和延髓组织中5-HIAA/5-HIT比值和MAOA含量均显著降低（P<0.05）;与Model组大鼠相比,Isoflurane组大鼠回肠5-HIAA含量、回肠/延髓5-HIAA/5-HT比值和MAOA含量均显著升高（P<0.05）。结论：异氟烷预处理可用于预防腹腔注射顺铂诱导的恶性呕吐,其机制可能与下降THP含量和提高MAOA含量,抑制5-HT合成以及促进5-HT代谢有关。     

Effects of Methadone on the Minimum Anesthetic Concentration of Isoflurane,and Its Effects on Heart Rate,Blood Pressure and Ventilation during Isoflurane Anesthesia in Hens (Gallus gallus domesticus)

The aim of this study was to measure the temporal effects of intramuscular methadone administration on the minimum anesthetic concentration (MAC) of isoflurane in hens, and to evaluate the effects of the isoflurane-methadone combination on heart rate and rhythm, blood pressure and ventilation. Thirteen healthy adult hens weighing 1.7 ± 0.2 kg were used. The MAC of isoflurane was determined in each individual using the bracketing method. Subsequently, the reduction in isoflurane MAC produced by methadone (3 or 6 mg kg^-1, IM) was determined by the up-and-down method. Stimulation was applied at 15 and 30 minutes, and at 45 minutes if the bird had not moved at 30 minutes. Isoflurane MAC reduction was calculated at each time point using logistic regression. After a washout period, birds were anesthetized with isoflurane and methadone, 6 mg kg^-1 IM was administered. Heart rate and rhythm, respiratory rate, blood gas values and invasive blood pressure were measured at 1.0 and 0.7 isoflurane MAC, and during 45 minutes after administration of methadone once birds were anesthetized with 0.7 isoflurane MAC. Fifteen minutes after administration of 3 mg kg^-1 of methadone, isoflurane MAC was reduced by 2 (-9 to 13)% [logistic regression estimate (95% Wald confidence interval)]. Administration of 6 mg kg^-1 of methadone decreased isoflurane MAC by 29 (11 to 46)%, 27 (-3 to 56)% and 10 (-8 to 28)% after 15, 30 and 45 minutes, respectively. Methadone (6 mg kg^-1) induced atrioventricular block in three animals and ventricular premature contractions in two. Methadone caused an increase in arterial blood pressure and arterial partial pressure of carbon dioxide, while heart rate and pH decreased. Methadone, 6 mg kg^-1 IM significantly reduced isoflurane MAC by 30% in hens 15 minutes after administration. At this dose, methadone caused mild respiratory acidosis and increase in systemic blood pressure.     

In Vitro Induction of Endothelial Apoptosis of the Post-Hypoxic Blood-Brain Barrier by Isoflurane but Not by Sevoflurane and Midazolam

Background

The effects of anesthetics on the injured brain continue to be the subject of controversial discussion. Since isoflurane has recently been shown to induce apoptosis of cerebral endothelial cells, this study compared different anesthetic compounds regarding their potential to induce cerebro-vascular apoptosis.

Methods

The in vitro model of the blood-brain barrier used in this study consisted of astrocyte-conditioned human umbilical vein endothelial cells (AC-HUVEC) has been used. After 24 h of deep hypoxia and reoxygenation or control treatment, AC-HUVEC were exposed to 0, 0.5, 1.0, or 2.0 times the minimum alveolar concentration of isoflurane or sevoflurane, or 0, 75, 150, or 300 nM of midazolam for 2 h. After 24 h, AC-HUVEC were harvested, and the degree of apoptosis was assessed by means of Western blots for the Bax and Bcl-2 ratio and, for controls and the highest concentration groups, terminal deoxynucleotidyl-mediated dUTP-biotin nick end labeling (TUNEL).

Results

Without hypoxic pretreatment, 2.0 MAC of isoflurane slightly increased TUNEL intensity compared to control and sevoflurane, but without any significant changes in the Bax and Bcl-2 ratio. After hypoxic pretreatment, exposure to isoflurane led to a multifold increase in the Bax and Bcl-2 ratio in a dose dependent manner, which was also significantly higher than the ratio observed in the 2 MAC sevoflurane group. TUNEL intensity in the post-hypoxic 2 MAC isoflurane group was increased by a factor of 11 vs. control and by 40 vs. sevoflurane. Sevoflurane and midazolam did not significantly alter these markers of apoptosis, when compared to the control group.

Conclusions

Isoflurane administered after hypoxia elevates markers of apoptosis in endothelial cells transdifferentiated to the cerebro-vascular endothelium. Endothelial apoptosis may be a previously underestimated mechanism of anesthetic neurotoxicity. Administration of high concentrations of isoflurane in experimental settings may have negative effects on the blood-brain barrier.     

Effect of isoflurane, atracurium, fentanyl, and noxious stimulation on bispectral index in pigs

The study reported here was done to determine the relationship between anesthesia depth and bispectral index (BIS) in stimulated pigs. Isoflurane minimal alveolar concentration (MAC) was determined using the tail-clamp method in 16 Yorkshire/Landrace-cross pigs with mean+/-SEM weight of 27.7+/-1.76 kg. One week later, BIS, ECG, heart rate, arterial blood pressure, esophageal temperature, end-tidal CO2 tension and isoflurane concentration, arterial pH, PaO2, PaCO2, plasma bicarbonate concentration, and base excess were determined at each of five isoflurane MAC-multiples: 0.8, 1.0, 1.3, 1.6, and 2.0. Six treatments were studied: isoflurane; isoflurane and atracurium; isoflurane, atracurium, and fentanyl; isoflurane with noxious stimulation; isoflurane and atracurium with noxious stimulation; and isoflurane, atracurium, and fentanyl with noxious stimulation. The noxious stimulus during BIS measurement was the same as that for MAC determination. Each pig was studied three times (n = 8), and order of MAC-multiples and treatments was randomized. Data were evaluated by use of general linear model analysis of variance and linear regression analysis, with statistical significance set at P < 0.05. Significant differences in BIS values were identified between MAC-multiples within each treatment and between treatment 3 compared with treatments 2 and 4. Significant differences also were observed within and between treatments for heart rate, arterial blood pressure, and PaO2. Use of BIS appears reliable for identification of light versus deep anesthesia, but is of limited use for discrimination between isoflurane MAC-multiples of 1 and 1.6. We conclude that, compared with other treatments, atracurium and noxious stimulation had no significant effect on BIS.     

不同浓度七氟醚联合瑞芬太尼对腹腔镜胆囊切除术患者应激反应和认知功能的影响

摘要 目的：探讨不同浓度七氟醚联合瑞芬太尼对腹腔镜胆囊切除术（LC）患者应激反应和认知功能的影响。方法：选择2022年6月至2022年12月期间在扬州大学附属医院接受LC的患者120例,按照随机数字表法将患者分为低浓度组[1.0最低肺泡有效浓度（MAC）七氟醚联合瑞芬太尼,n=60]和高浓度组（1.5MAC七氟醚联合瑞芬太尼,n=60）。对比两组血流动力学指标[心率（HR）、收缩压（SBP）、舒张压（DBP）]、苏醒质量、应激反应指标[超氧化物歧化酶（SOD）、丙二醛（MDA）、总抗氧化能力（T-AOC）]、认知功能和不良反应发生情况。结果：低浓度组插管后即刻（T1）~拔管时（T5）时间点HR、SBP、DBP高于高浓度组（P<0.05）。低浓度组的自主呼吸时间、苏醒时间、拔管时间、定向力恢复时间短于高浓度组（P<0.05）。两组术后1h SOD、T-AOC均下降,但低浓度组高于高浓度组（P<0.05）。两组术后1h MDA升高,但低浓度组低于高浓度组（P<0.05）。低浓度组术后6 h、术后12 h、术后24 h简易精神状态检查量表（MMSE）评分高于高浓度组（P<0.05）。两组不良反应发生率组间对比未见差异（P>0.05）。结论：与1.5MAC七氟醚相比,1.0MAC 七氟醚联合瑞芬太尼应用于LC患者的效果更好,可保持血流动力学平稳,有效控制机体的应激反应,同时还可减轻认知功能影响,提高苏醒质量。     

Effect of midazolam and butorphanol premedication on inhalant isoflurane anesthesia in mice

Isoflurane is a representative inhalant anesthesia used in laboratory animals. However, isoflurane mediates respiratory depression and adverse clinical reactions during induction. In the present study, we established a novel balanced anesthesia method in mice that combined isoflurane anesthesia with midazolam and butorphanol (MB). Thirty-four male C57BL/6J mice received either isoflurane alone or isoflurane with an intra-peritoneal MB premedication (3 mg/kg midazolam and 4 mg/kg butorphanol). The minimum alveolar concentration (MAC) in each group was evaluated. Induction time and adverse clinical reactions were recorded in each group. Core body temperature, heart rate, respiratory rate, and oxygen saturation (SPO₂) were assessed before and for 1 h after induction. Premedication with MB achieved a significant reduction in MAC compared with isoflurane monoanesthesia (isoflurane, 1.38 ± 0.15%; isoflurane with MB, 0.78 ± 0.10%; P<0.05). Induction time was significantly shortened with MB premedication, and adverse reactions such as excitement or incontinence were observed less frequently. Furthermore, isoflurane anesthesia with MB premedication caused increase of respiratory rates compared to isoflurane monoanesthesia. No significant decrease of SPO₂ was observed in MBI anesthesia, while a decrease in SPO₂ was apparent with isoflurane monoanesthesia (baseline, 98.3% ± 1.1; 10 min after induction, 91.8 ± 6.4%; P<0.05). In conclusion, premedication with MB was effective for the mitigation of respiratory depression induced by isoflurane in mice, with rapid induction and fewer adverse clinical reactions.