异丙酚对鼠心肌细胞缺氧/复氧损伤中的保护作用

心肌缺血/再灌注损伤是围术期经常面临的一种病理生理变化,静脉麻醉药异丙酚结构上的特殊性使其对各种因素（如缺血/再灌注）所致的氧化应激的诸多环节均有阻断作用,异丙酚的抗氧化性可能为其心肌保护作用的机制之一。本文研究了异丙酚预处理对心肌细胞缺氧/复氧损伤的保护作用及该作用是否与其抗氧化性有关。     

硫酸锌预处理对成年大鼠缺氧／复氧心肌细胞超微结构的影响

目的：研究硫酸锌预处理对成年大鼠缺氧／复氧心肌细胞超微结构的影响。方法：分离培养SD成年大鼠心肌细胞,建立心肌细胞缺氧／复氧损伤模型,将细胞随机分为正常组（N）,缺氧复氧组（H／R）,缺氧预处理组（HP）,硫酸锌（ZnSO4）预处理组（ZnP）,分别进行相应处理,然后用透射电镜对各组心肌细胞超微结构进行观察,并进行线粒体评分。结果：N组、HP组、ZnP组超微结构优于H／R组,线粒体评分较H／R组低（P〈0．05）,HP组、ZnP组超微结构变化相似且线粒体评分无统计学差异,但均高于N组（P〈0．05）。结论：缺氧／复氧可造成成年大鼠心肌细胞超微结构的损伤,ZnSO4预处理、缺氧预处理均能减轻这种损伤,且两者效果相当。     

自噬和PI3K-Akt-mTOR信号转导通路在缺氧预处理对高糖心肌细胞缺氧/复氧损伤保护中的作用

目的 探讨自噬和磷脂酰肌醇3激酶（phosphatidylinositol 3 hydroxy kinase, PI3K）-蛋白激酶B（protein kinase B, Akt）-雷帕霉素靶蛋白（mammalian target of rapamycin, mTOR）信号转导通路在缺氧预处理（hypoxia preconditioning, HPC）对高糖心肌细胞缺氧/复氧（anoxia/reoxygenation, AR）损伤中的作用及机制。 方法 将采用高糖培养基培养72 h的心肌细胞用随机数字表法分为5组：空白对照组（S组）、AR损伤对照组（AR组）、HPC组、渥曼青霉素＋HPC组（Wo＋HPC组）、雷帕霉素＋HPC组（Ra＋HPC组）。采用乳酸脱氢酶（lactate dehydrogenase, LDH）检测试剂盒检测心肌细胞LDH漏出率,Annexin V/PI双染流式细胞术检测心肌细胞凋亡情况,蛋白印迹法检测心肌细胞微管相关蛋白1轻链3（microtubulesas sociated protein light, LC3）-Ⅱ、Beclin-1、mTOR、PI3K表达和磷酸化（phospho, p）蛋白激酶B/蛋白激酶B（p-Akt/Akt）比值。 结果 与AR组比较,Wo＋HPC组LDH漏出率、早期和晚期凋亡率降低（P〈0.05）,LC3-Ⅱ和Beclin-1表达降低（P〈0.05）,mTOR、PI3K表达和p-Akt/Akt比值升高（P〈0.05）。HPC组各指标与AR组比较,差异均无统计学意义（P〉0.05）。与HPC组比较,Wo＋HPC组LDH漏出率、早期和晚期凋亡率降低（P〈0.05）,Beclin-1表达降低（P〈0.05）,mTOR、PI3K表达和p-Akt/Akt比值升高（P〈0.05）。 结论 激活PI3K-Akt-mTOR信号转导通路抑制自噬可明显改善HPC对高糖心肌细胞AR损伤的保护作用。     

PKC在缺氧预处理和去甲肾上腺素预处理减轻乳鼠心肌细胞缺氧复氧损伤中的作用

目的 评价蛋白激酶C(PKC)在缺氧预处理和去甲肾上腺素预处理减轻乳鼠心肌细胞缺氧复氧损伤中的作用.方法 原代培养乳鼠心肌细胞,随机分为6组(n=25):对照组(Ⅰ组)常规培养;缺氧复氧组(Ⅱ组)细胞缺氧3 h,复氧1 h;缺氧预处理组(Ⅲ组)缺氧20 min,复氧20 min后制备缺氧复氧模型;去甲肾上腺素预处理组(Ⅳ组)细胞经终浓度为10-7 mol/L去甲肾上腺素孵育30 min后,去除去甲肾上腺素,再行缺氧复氧;H7+缺氧预处理组(Ⅴ组)细胞经终浓度为5×10-5 mol/L的H7孵育10 min后,去除H7,其余操作同Ⅲ组;H7+去甲肾上腺素预处理组(Ⅵ组)细胞经终浓度为5×10-5 mol/L的H7(PKC活性抑制剂)孵育10 min后,去除H7,其余操作同Ⅳ组.复氧结束后,测定心肌细胞存活率、培养液乳酸脱氢酶(LDH)、肌酸激酶(CK)活性和心肌细胞MDA含量和SOD活性.结果 与Ⅰ组比较,Ⅱ组细胞存活率和SOD活性降低,LDH、CK的活性及MDA含量升高(P＜0.01).与Ⅱ组比较,Ⅲ组和Ⅳ组细胞存活率和SOD活性升高,LDH、CK活性及MDA含量降低(P＜0.01).与Ⅲ组比较,Ⅴ组细胞存活率和SOD活性降低,LDH、CK活性及MDA含量升高(P＜0.01).与Ⅳ组比较,Ⅵ组细胞存活率和SOD活性降低,LDH、CK活性及MDA含量升高(P＜0.05).结论 PKC激活参与了缺氧预处理与去甲肾上腺素预处理减轻乳鼠心肌细胞缺氧复氧损伤.     

低温对二氮嗪预处理减轻大鼠海马神经元缺氧复氧损伤的作用

脑缺血再灌注损伤是一个多因素、多环节的恶性级联过程，针对不同环节发挥作用的保护措施联合应用比单一保护措施更有效。低温简单易行，安全范围大，是当前较为重要的脑保护措施，但低温并不能完全消除脑损伤。有研究表明，选择性线粒体内膜ATP敏感性钾通道（Mito-KATP）开放剂二氮嗪可减轻缺氧复氧性脑损伤。但低温对二氮嗪预处理减轻大鼠海马神经元缺氧复氧损伤的作用尚需进一步探讨。本研究拟观察低温对二氮嗪预处理减轻大鼠海马神经元缺氧复氧损伤的作用，为临床研究提供理论依据。     

地氟醚、七氟醚和异氟醚预处理对缺氧/复氧心肌细胞损害的保护作用

目的　研究地氟醚、七氟醚和异氟醚预处理对心肌细胞缺氧／复氧损害的保护作用。方法　原代培养乳鼠心肌细胞，随机分为对照、单纯缺氧／复氧及 １．５ＭＡＣ地氟醚、七氟醚和异氟醚预处理５组。实验结束测定乳酸脱氢酶（ＬＤＨ）和肌酸激酶（ＣＫ）活性、细胞存活和凋亡率。结果　与对照组比，单纯缺氧／复氧使ＬＤＨ、ＣＫ和细胞凋亡率升高及细胞存活率显著下降（Ｐ＜０．０１）；１．５ＭＡＣ地氟醚、七氟醚和异氟醚预处理显著减轻ＬＤＨ、ＣＫ和细胞凋亡率升高及细胞存活率下降，其中七氟醚减轻作用最强。结论　地氟醚、七氟醚和异氟醚预处理对心肌细胞缺氧／复氧损害有一定的保护作用，七氟醚的保护作用可能更强。     

二氮嗪预处理对大鼠海马神经细胞缺氧复氧损伤的影响

缺血预处理(IPC)被认为是所能得到的最强的心肌内源性保护之一。研究表明，这种奇异的预处理保护还存在于神经组织。本研究拟采用原代培养海马神经元的离体模型，排除活体状态下复杂的多因素(如血管、侧支循环、血液、血压、体温以及周围环境等)干扰，直接观察KATP通道开放剂二氮嗪对细胞缺氧复氧损伤的影响。     

在体外乳鼠心肌细胞缺氧的损伤及利多卡因的保护作用

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P物质对高糖孵育心肌细胞缺氧／复氧损伤的影响

目的：探讨P物质预处理对高糖孵育大鼠心肌细胞缺氧／复氧损伤的影响。方法：分离新生SD大乳鼠心脏为细胞悬液接种于细胞培养板,分别用正常糖和高糖培养基进行孵育,72h后将细胞随机分为5组,分别为正常对照组,高糖对照组,另外三组进行缺氧／复氧（A／R）处理：高糖A／R组,高糖SP＋A／R组和高糖SP＋D—SP＋A／R组。复氧后分别测定细胞凋亡率、缺氧液和复氧液中caspase-3活性以及LDH释放量。结果：高糖和缺氧／复氧均可引起细胞凋亡率增高,缺氧液和复氧液中CasPase-3活性以及LDH释放量均显著升高：SP可降低上述各项指标,且该作用可被NK-1受体拮抗剂（D-SP）逆转。结论：高糖孵育可造成心肌细胞损伤,缺氧／复氧可加剧高糖孵育的大鼠心肌细胞损伤．SP预处理可显著减轻该损伤,且该作用可能由NK-1受体介导。     

地氟醚预处理对中性粒细胞介导心肌细胞缺氧/复氧损伤的保护作用

目的研究地氟醚预处理对中性粒细胞介导的心肌细胞的缺氧/复氧损伤的保护作用。方法 原代培养的SD乳鼠心肌细胞,随机分为四组:缺氧,复氧组、中性粒细胞介导缺氧,复氧组、地氟醚预处理组、地氟醚预处理 中性粒细胞介导缺氧/复氧组,各组缺氧前时测定乳酸脱氢酶(LDH)、肌酸激酶-MB(CK-MB)活性、肌钙蛋白T(TnT)浓度和心肌细胞搏动频率,复氧后测定LDH、CK-MB活性、TnT浓度、心肌细胞搏动频率、心肌存活率和节律失常发生率。结果 除地氟醚预处理组外,各组缺氧前和复氧后各指标差异均有显著性(P<0.05或0.01)。LDH、CK—MB活性缺氧前和复氧后时的差值、心肌存活率和节律失常发生率在各组间差异有显著性(P<0.01),TnT缺氧前和复氧后的差值组间无明显差异(P>0.05)。组间地氟醚预处理 中性粒细胞介导缺氧,复氧组较中性粒细胞介导缺氧/复氧组LDH、CK—MB活性缺氧前和复氧后的差值及节律失常发生率降低(P<0.01),心肌细胞存活率明显升高(P<0.01),但仍不如单纯缺氧/复氧组上述指标。结论 地氟醚减轻中性粒细胞介导的缺氧/复氧损伤,但不能完全阻断其心肌细胞的损伤。     

人参皂苷单体Re对大鼠心肌细胞缺氧的作用

目的 观察人参皂苷单体Re对大鼠心肌细胞缺氧的保护作用并探讨其机制.方法 SD大鼠乳鼠心肌细胞原代培养,按照随机数字表法分为5组,每组6个样本.正常对照组细胞常规培养;缺氧对照组细胞常规培养48 h再缺氧培养12 h;另外3组细胞先常规培养48 h,分别用20、40、80 g/L人参皂苷单体Re预处理30 min再缺氧12 h,相对应设为单体Re低、中、高浓度组.采用ELISA法检测心肌细胞上清液中乳酸脱氢酶(LDH)活性,荧光漂白恢复(FRAP)实验观察细胞间连接通讯,以FRAP率表示结果.数据处理行组间或配对t检验.结果 (1)与缺氧对照组细胞LDH活性[(403±22)U/L]比较,单体Re低、中、高浓度组均明显降低,分别为(255±16)、(241±13)、(237±24)U/L(t值分别为5.1、5.2、8.3,P值均小于0.05).(2)细胞经激光淬灭后10 min,正常对照组FRAP率为(74.8±3.6)%;缺氧对照组FRAP率为(13.2±5.6)%;单体Re低、中、高浓度组FRAP率分别为(34.3±3.9)%、(36.2±3.1)%、(39.5±2.9)%,与缺氧对照组比较,差异均有统计学意义(t值分别为18.3、-41.9、-6.6,P值均小于0.05).结论 采用人参皂苷单体Re预处理可降低缺氧大鼠心肌细胞LDH的释放,明显改善细胞间连接通讯,对缺氧心肌细胞有明显的保护作用,剂量尤以20 g/L为适宜.

Abstract：

Objective To investigate the protective effect of ginsenoside Re on myocardial cells of neonatal SD rat with hypoxia injury,and to explore its mechanism. Methods The primary passage of myocardial cells collected from neonatal SD rats were divided into A group (with ordinary treatment),B group[exposed to hypoxia (1% O2,5% CO2,94% N2) for 12 hours after being cultured for 48 hours],C group (pretreated with 80 g/L ginsenoside Re for 30 minutes after 48 hours of ordinary culture,then exposed to hypoxia for 12 hours),D group (received the same treatment as used in C group except for using 40 g/L ginsenoside Re),E group (received the same treatment as used in C group except for using 20 g/L ginsenoside Re) according to the random number table,with 6 samples in each group. Myocardial cell supernatants were collected for determination of content of lactate dehydrogenase (LDH) with enzyme linked immunosorbent assay. Fluorescence recovery after photobleaching technique was used to detect gap junction intercellular communication (GJIC).Result was observed by laser scanning confocal microscope. Data were processed with paired t test. Results (1) Compared with that in B group[(403±22)U/L],contents of LDH in E,D,and C groups were obviously decreased[(255±16),(241±13),(237±24)U/L,with t value respectively 5.1,5.2,8.3,P values all below 0.05]. (2) The fluorescence recovery rate in A group was (74.8±3.6)% 10 min after quenching,which was higher than that in B group[(13.2±5.6)%,t=15.2,P<0.01]. The fluorescence recovery rate in C,D,and E groups was respectively (39.5±2.9)%,(36.2±3.1)%,and (34.3±3.9)% 10 min after quenching,all higher than that in B group (with t value respectively -6.6,-41.9,18.3,P values all below 0.05). Conclusions Ginsenoside Re pretreatment,particularly with a dose of 20 g/L,can protect myocardial cells from hypoxia injury,and the effect may be attributable to inhibition of release of LDH and improvement of the GJIC function.     

异丙酚预先给药对缺氧复氧鼠脑神经元的保护作用

目的：观察异丙酚预先给药对缺氧复氧鼠脑神经元神经细胞活力、一氧化氮(NO)产量、热休克蛋白(Hsp70)和Hsp70 mRNA表达的影响，探讨异丙酚有无脑保护作用及其机制。方法:培养12d的胎鼠大脑神经元，随机分为四组：Ⅰ组(正常对照组)；Ⅱ组(缺氧复氧组)；Ⅲ组(14μmol／L异丙酚预处理组)；Ⅳ组(56μmol／L异丙酚预处理组)。Ⅲ组和Ⅳ组于缺氧前1h分别换入含有14μmol／L和56μmol／L异丙酚的培养液，随后置入95％N2 5％CO2培养箱中缺氧30min。四组于复氧的1、2、4、6、24h(分别记为T1、T2、T4、L、L)分别用MTT(改良四甲基偶氮唑盐)细胞酶学分析法和硝酸还原酶法测定神经元神经细胞活力(用OD值表示)和NO产量，同时四组于复氧的1、3、8、24、48、72h分别用原位杂交法和免疫组化法观察Hsp70 mRNA及Hsp70阳性细胞百分率。结果与Ⅰ组相比，Ⅱ组T1-24各时点OD值降低；Ⅲ组、Ⅳ组T1、T2时点OD值升高；与Ⅱ组相比，Ⅲ组、Ⅳ组OD值均升高；Ⅲ组、Ⅳ组间差异无显著性。在T1、T2及T4时点，与Ⅰ组相比，Ⅱ组NO产量增高；与Ⅱ组相比，Ⅲ组、Ⅳ组NO产量降低；Ⅰ组与Ⅲ组、Ⅰ组与Ⅳ组、Ⅲ组与Ⅳ组间差异无显著性。与Ⅰ组相比，Ⅱ组Hsp70 mRNA及Hsp70阳性细胞百分率增高，且开始增高的时间分别为3h和8h，高峰时间分别为24h和48h；与Ⅰ组相比，Ⅲ组、Ⅳ组Hsp70 mRNA阳性细胞百分率高峰提前至8h；Ⅲ、Ⅳ组间差异无显著性；与Ⅱ组和Ⅲ组相比，Ⅳ组Hsp70高峰提前至24h，而Ⅲ组与Ⅱ组差异无显著性。结论:异丙酚预先给药可抑制缺氧复氧引发的神经细胞活力降低，减轻神经细胞的缺氧复氧性损伤，这可能与异丙酚可抑制NO产量增高及分别从转录和翻译两个水平诱导鼠脑神经元Hsp70 mRNA和Hsp70的表达高峰提前有关。     

Anti-inflammatory effect of erythropoietin pretreatment on cardiomyocytes with hypoxia/reoxygenation injury and the possible mechanism

Objective： To investigate the anti-inflammatory effect of erythropoietin （EPO） pretreatment on cardiomyocytes exposed to hypoxialreoxygenation injury （H/R） and explore the possible mechanism.
Methods： The cultured neonatal rats＇ ventricular cardiomyocytes were divided randomly into 4 groups, control group （C group）, EPO pretreatment group （E group）, EPO and pyrrolidine dithiocarbamate （PDTC） pretreatment group （EP group） and PDTC pretreatment group （P group）. After 24 hours＇ pretreatment, the cardiomyocytes were exposed to H/R. After pretreatment and H/R, the expression of tumor necrosis factor- α （TNF- α ） gene in all the groups was detected by RT-PCR and Western blot. The nuclear factor- κ B （NF- κB） activity was detected by electrophoretic mobility shift assay （EMSA） and the inhibitor- κB α （Ⅰ- κB α） protein level was detected by Western blot.
Results： The decrement of Ⅰ- κB a protein and the increasing NF- KB activity were found in cardiomyocytes pretreated with EPO before H/R compared to other groups （t=3.321, 4.183, P〈0.01）. However, after H/R, NF- κB activity and expression of TNF- α gene were significantly reduced, Ⅰ- κB a protein expression was increased in cardiomyocytes of E group compared to other groups （t=-3.425, 3.687, 3.454, P〈0.01）. All theses changes caused by EPO pretreatment were eliminated by the intervention of PDTC （an antagonist to NF- κB） during pretreatment.
Conclusions： EPO pretreatment can inhibit the activation of NF- κB and upregulation of TNF- α gene in cardiomyocytes exposed to H/R through a negative feedback of NF- κB signaling pathway, and thus produces the anti-inflammatory effect. This might be one of the ways EPO produces the anti-inflammatory effect.     

异丙酚预处理对大鼠离体心脏缺血-再灌注损伤的影响

目的 探讨异丙酚预处理对心肌缺血-再灌注(I-R)损伤的作用及其机制。方法 成年雄性 SD 大鼠18只，随机分为对照组(C组)、I-R 组、50μmol/L 异丙酚预处理组(P组)，每组6只。建立Langendorff 离体心脏灌流模型，平衡35min 后 I-R 组和 P 组均停灌30min，然后复灌120min。其中 P 组停灌前用含50μmol/L 异丙酚的 K-H 液灌流10min，并用无异丙酚的 K-H 液冲洗10min。C 组不停灌，也不用异丙酚处理。灌流结束后，制备心肌组织匀浆，测定 NO 含量、总 NOS 及超氧化物歧化酶(SOD)活性，用免疫组化 SABC 染色检测诱导型 NOS(iNOS)蛋白与血红素氧化酶-1(HO-1)蛋白表达水平，同时行光镜及透射电镜观察。结果病理学显示 C 组正常，I-R 组心肌组织严重损伤，P 组轻度损伤；与C 组相比，I-R 组和 P 组 iNOS、HO-1蛋白表达量和 iNOS 活性均升高，cNOS 活性均降低(P<0.05或0.01)；I-R 组总 NOS 活性和 NO 含量、Cu.Zn-SOD、Mn-SOD 和总 SOD 活性均降低(P<0.05或0.01)，但P 组无变化(P>0.05)。与 I-R 组比较，P 组除 iNOS 活性不变外，其余指标均升高(P<0.05或0.01)。结论 异丙酚预处理对心肌 I-R 损伤具有保护作用，其机制在于抑制或清除氧自由基以降低氧化应激水平，并通过恢复 cNOS 活性而增加 NO 的含量。     

地氟醚预处理对缺血再灌注心肌的保护作用

目的 从细胞生化、心脏收缩性能和心肌细胞超微结构等方面来探讨地氟醚对心肌缺血再灌注损伤的影响。方法 采用改良Ｌａｎｇｅｎｄｏｒｆｆ离休大鼠心脏模型,将３０只大鼠随机分成３组：对照组（Ｃ）、缺血再灌注组（Ｉ－Ｒ组）和地氟醚组（Ｄ组）,每组各１０只,常温全心停灌３０分钟,再灌注３０分钟。结果 停灌前给１ＭＡＣ的地氟醚可以明显降低心肌丙二醛（ＭＤＡ）含量,促进心脏收缩功能的恢复和减轻心肌组织超微结构的损     

PI3K/Akt信号通路在乳化异氟醚预先给药减轻乳鼠心肌细胞缺氧复氧损伤中的作用

目的 评价磷脂酰肌醇-3激酶/蛋白质丝氨酸苏氨酸激酶(PI3K/Akt)信号通路在乳化异氟醚预先给药减轻乳鼠心肌细胞缺氧复氧损伤中的作用.方法 Wistar乳鼠60只,乳鼠心肌细胞于24孔培养板原代培养后,采用缺氧2 h复氧2 h建立缺氧复氧模型.乳鼠心肌细胞随机分为6组,每组8孔,正常对照组(C组):按正常条件继续培养4 h;A/R组:制备缺氧复氧模型;EI组:于细胞缺氧前即刻在培养液中加入乳化异氟醚,终浓度为1.68 mmol/L;EI+wortmannin(PI3K特异性抑制剂)组(EIW组):于细胞缺氧前即刻在培养液中加入乳化异氟醚和wortmannin,终浓度分别为1.68 mmol/L和100 nmol/L;wortmannin组(W组):于细胞缺氧前即刻在培养液中加入wortmannin,终浓度为100 nmol/L;脂肪乳组(F组):与细胞缺氧前即刻在培养液中加入30%脂肪乳,终浓度为0.05%.复氧2 h时,取细胞培养上清液测定乳酸脱氢酶(LDH)活性、肌钙蛋白I(cTnI)浓度,心肌细胞匀浆后测定超氧化物歧化酶(SOD)活性与丙二醛(MDA)含量,并测定心肌细胞磷酸化Akt(p-Akt)的表达水平.结果 与C组比较,其余5组上清液LDH活性、cTnI浓度和心肌细胞MDA含量升高,心肌细胞SOD活性降低(P<0.05);与A/R组比较,EI组和EIW组上清液LDH活性、cTnI浓度和心肌细胞MDA含量降低,心肌细胞SOD活性升高,F组除心肌细胞SOD活性升高外(P<0.05),其余指标差异均无统计学意义(P>0.05),W组上述指标差异无统计学意义(P>0.05);与EI组比较,EIW组、W组和F组上清液LDH活性、cTnI浓度和心肌细胞MDA含量升高,心肌细胞SOD活性降低(P<0.05).C组、EIW组、H/R组、F组和EI组心肌细胞p-Akt表达水平依次升高(P<0.05).结论 乳化异氟醚预先给药减轻乳鼠心肌细胞缺氧复氧损伤可能与进一步激活PI3K/Akt信号通路有关.     

c-jun反义基因重组体转染对缺氧复合烧伤血清刺激下大鼠心肌细胞的保护作用

目的 观察c-jun反义基因重组体转染对缺氧复合烧伤血清刺激下大鼠心肌细胞的保护作用。方法 培养大鼠心肌细胞，分为：(1)正常对照组；(2)转染组：构建c-jun反义基因重组体并转染人心肌细胞，随后进行缺氧复合烧伤血清刺激；(3)非转染组：仅进行缺氧复合烧伤血清刺激，不作其他处理。于刺激后l、3、7h，采用逆转录聚合酶链式反应(RT-PCR)检测c-jun mRNA的表达变化；用Western blot检测c-jun蛋白、肌钙蛋白T(TnT)和β-微管蛋白的表达变化；在光镜和电镜下观察心肌细胞形态结构改变。结果 (1)与正常对照组比较，非转染组c-jun mRNA与蛋白表达显，转染组较非转染组显下降。(2)与正常对照组比较，非转染组TnT与β-微管蛋白表达显下降，转染组较非转染组明显回升。(3)转染组心肌细胞骨架结构基本保持完好，偶见断裂与溶解。非转染组骨架网状结构紊乱、溶解与断裂，呈颗粒状。结论 缺氧复合烧伤血清刺激可使大鼠心肌细胞c-jun表达上调，进而引起心肌细胞损伤，c-jun反义基因重组体转染对该刺激条件下的心肌细胞具有保护作用。     

Protective effects of isoflurane pretreatment in endotoxin-induced lung injury

BACKGROUND: The concept of antiinflammatory effects of volatile anesthetics is well established in vitro and in some organ systems. Their protective role in lung injury, however, remains to be elucidated. The authors hypothesized that in the lung, isoflurane pretreatment may attenuate neutrophil infiltration and reduce endotoxin-induced injury. METHODS: Male C57Bl/6 mice were exposed to aerosolized lipopolysaccharide. Neutrophil recruitment into the pulmonary vasculature and migration into the different lung compartments (interstitium and alveolar air space) were determined by flow cytometry. Capillary protein leakage, formation of lung edema, and concentration of the chemokines keratinocyte-derived chemokine (CXCL1) and macrophage inflammatory protein 2 (CXCL2/3) in bronchoalveolar lavage were compared in mice with or without isoflurane treatment (1.4% inspired for 30 min) at different times before and after endotoxin exposure. RESULTS: Endotoxin inhalation induced significant neutrophil migration into all lung compartments. Isoflurane pretreatment attenuated both neutrophil recruitment into lung interstitium and alveolar space when given 1 or 12 h before or 1 h after lipopolysaccharide but not at 4, 6, or 24 h before endotoxin exposure. Isoflurane pretreatment 1 or 12 h before lipopolysaccharide also reduced protein leakage and pulmonary edema. Production of CXCL1 and CXCL2/3 in the bronchoalveolar lavage was reduced when isoflurane was given 1 h but not 12 h before lipopolysaccharide, suggesting different mechanisms for early and late protection. CONCLUSION: Isoflurane pretreatment reduces acute lung injury when given 1 or 12 h before an endotoxin challenge or within the first hour of an already established inflammation.     

Protective effects of clarithromycin in rats with hypoxia/reoxygenation-induced intestinal injury

Background

This study was designed to determine the role of oxidative stress, nitric oxide (NO), and glutathione-related antioxidant enzymes in rat pups with hypoxia/reoxygenation (H/R)-induced bowel injury and to evaluate the potential benefits of prophylactic clarithromycin.

Methods

One-day-old Wistar albino rat pups (N = 21) were randomly divided into 3 groups: group I (control), group II (exposed to H/R), and group III (clarithromycin + H/R). Clarithromycin was administered (40 mg/kg) subcutaneously to group III for 3 days. On the fourth day, all rats except controls were exposed to H/R and were killed at 6 hours after H/R. Histopathologic injury scores (HIS), malonyldialdehyde, glutathione (GSH), glutathione-peroxidase (GSH-Px) activities, and NO levels were measured on intestinal samples.

Results

Whereas there was no difference for malonyldialdehyde levels among groups, HIS and NO levels were higher in group II than groups I and III (P < .05). However, GSH and GSH-Px activities were lower in group II than groups I and III (P < .05). Clarithromycin significantly increased GSH and GSH-Px activities and reduced HIS and NO levels in group III.

Conclusion

This study showed that oxidative stress and NO contributed to the pathogenesis of H/R-induced bowel injury and that clarithromycin had a protective effect on bowel injury owing to anti-inflammatory and antioxidant effects.     

Protective effects of Y-27632 on hypoxia/reoxygenation-induced intestinal injury in newborn rats

Background/Purpose

Necrotizing enterocolitis (NEC) is a major cause of mortality in neonates and is associated with a disruption in the protective intestinal barrier. The precise cause of NEC is elusive. However, ischemia/reperfusion injury of the intestine has been considered a major contributing factor. We examined the role of Y-27632, a selective Rho-kinase inhibitor, on a hypoxia/reoxygenation (H/R)-induced intestinal injury of newborn rat pups.

Methods

Hypoxia/reoxygenation was achieved by placing rat pups in an airtight chamber aerated with 95% N₂ + 5% CO₂ for 10 minutes followed by 10-minute 100% oxygen. Forty newborn rat pups were randomly allocated into 4 groups. Group 1 served as untreated controls. The pups in group 2 were subjected to H/R only. In groups 3 and 4, the rats were treated with intraperitoneal injection of 0.3 and 3 mg kg⁻¹ day⁻¹ of Y-27632 for 5 days following H/R, respectively. The pups were killed 6 days following the H/R injury. Intestine specimens were evaluated for histopathology and biochemical investigation.

Results

The microscopic lesions in H/R rat pups were virtually the same as those seen in neonatal NEC, with severe destruction of villi and crypts. Hypoxia/reoxygenation resulted in significant elevation in malondialdehyde levels, but decreased tissue nitric oxide levels (P < .05). Protective effects of Y-27632 on H/R-induced intestinal injury of newborn rat pups were observed with a significant decrease in the intestinal injury score, suppression in malondialdehyde levels, and increase in nitric oxide levels (P < .05).

Conclusions

In this experimental study, Y-27632 significantly attenuated H/R-induced intestinal injury. These findings indicate that inhibition of Rho-kinase may offer a novel therapeutic approach in the treatment of NEC.