肠黏膜屏障缺血/再灌注损伤研究进展

肠黏膜缺血／再灌注损伤是肠黏膜的主要损伤因素之一。各种原因引起肠道的缺血缺氧,导致肠黏膜的缺血／再灌注损伤,影响肠黏膜屏障功能。与肠黏膜缺血／再灌注损伤有关的主要因素包括：氧自由基、细胞因子、核转录因子-kB、细胞凋亡等。本文就肠黏膜屏障缺血／再灌注损伤相关因素的研究进展予以综述。     

肠腔灌注高氧液对缺血-再灌注后肠黏膜屏障损伤的保护作用

目的探讨缺血期经肠腔灌注高氧液对家兔肠缺血-再灌注后肠黏膜屏障损伤的保护作用。方法健康家兔24只,随机均分成三组:缺血-再灌注组(I/R组)、高氧液处理组(HOS组)、假手术对照组(Sham组)。Sham组只开腹游离但不夹闭肠系膜上动脉(SMA),另两组用无损伤动脉夹夹闭SMA1h。HOS组于缺血期以20ml.kg-1.h-1恒速向肠腔灌注高氧液1h,I/R组则以相同的方式灌注等量的生理盐水,松开动脉夹再灌注2h后取标本。光镜下观察各组肠黏膜组织形态学改变,测定肠黏膜组织ATP含量和肠道的氧摄取率(ERO2);定量分析门静脉血中细菌内毒素(ET)含量;检测血清中肿瘤坏死因子α(TNF-α)、乳酸(Lac)水平;观察细菌移位率。结果与Sham组相比,I/R组光镜下肠黏膜损伤严重,肠黏膜组织ATP含量及肠道的ERO2均明显下降,血液中ET含量、Lac和TNF-α水平明显升高(P<0.05或P<0.01),同时出现了广泛的细菌移位;经肠腔灌注高氧液(HOS组)能够明显改善小肠黏膜损伤及上皮细胞形态学改变,显著提高肠黏膜组织ATP含量及ERO2;明显降低血液中ET、Lac和TNF-α水平(P<0.05或P<0.01),同时显著减少肠道细菌移位率(P<0.05)。结论肠腔灌注高氧液能够显著减轻肠缺血-再灌注引起的小肠黏膜屏障功能障碍,是一种安全有效的小肠保护方法。     

肝缺血再灌注对肠道损伤及细菌移位的研究进展

肝缺血再灌注损伤除了对肝脏损伤外,还可因肠组织缺血缺氧、再灌注损伤、内毒素血症、免疫屏障受损等引起肠黏膜上皮细胞脱落、坏死,增加小肠通透性,促发肠道细菌和内毒素移位,诱发MODS,并且肝脏损伤和肠道损伤相互形成恶性循环。因此,在肝缺血再灌注过程中,有效的保护肠黏膜屏障,防止细菌和内毒素移位,将减少肝切除、肝移植等手术的并发症,提高其存活率。     

硫化氢在肠缺血-再灌注损伤大鼠肠黏膜屏障功能障碍中的作用

目的 观察硫化氢(H_2S)在肠缺血.再灌注损伤大鼠肠黏膜屏障功能障碍中的作用.方法 雄性Wistar大鼠24只,分为S(假手术)组、Ⅰ(缺血-再灌注)组,N(缺血-再灌注+NaHS)组(n=8),N组在再灌注前10 min静脉注射100 μmol/kg NaHs后按每小时1 mg/kg持续静脉注射直到再灌注2 h,S和Ⅰ组静脉注射相同体积的生理盐水.采用改良的酶学分光光度法测定血浆D-乳酸水平,采用分光光度法检测小肠黏膜超氧化物歧化酶(SOD)和髓过氧化物酶(MPO)、丙二醛(MDA)、黄嘌呤氧化酶(XO)水平,敏感硫电极法检测硫化氢(H_2S)浓度.电镜下观察肠黏膜形态学改变,TUNEL染色观察小肠上皮细胞凋亡指数(AI),逆转录.聚合酶链反应(RT-PCR)法检测小肠黏膜组织胱硫醚-γ-裂解酶(CSE)、胱硫醚-β-合酶(CBS)、多聚ADP核糖合成酶(PARP)和细胞凋亡蛋白酶(Caspase)-3 mRNA的表达,蛋白质印迹法检测小肠黏膜PARP和Caspase-3蛋白水平.结果 N组D-乳酸含量、AI分别为(2.35±0.26)mg/L、(24.41±2.76)%,低于Ⅰ组、高于S组(P<0.01),两者正相关(r=0.892,P<0.01);N组MDA、XO分别为(9.17±0.35)nmol/mg、(9.94±0.41)U/g,低于Ⅰ组、高于S组(P<0.01),两者正相关(r=0.995,P<0.01);N组CSE mRNA、H_2S、SOD、MPO分别为(0.33±0.02)μmol/L、(35.27±3.14)μmol/L、(8.83±0.29)U/mg、(5.95±0.49)U/mg;N组CSE mRNA、H_2S、SOD水平均低于S组(P<0.01),N组H2S、SOD水平均高于Ⅰ组(P<0.01),N组MPO水平高于S组、低于Ⅰ组(P<0.01);N组活化的Caspase-3、PARP蛋白表达量分别为11.50±1.25、9.37±1.18,高于s组、低于Ⅰ组(P<0.01),两者正相关(r=0.785,P<0.01).结论 H_2S对肠缺血再灌注损伤大鼠肠黏膜屏障功能障碍有保护作用,其机制之一是减少中性粒细胞浸润和激活、肠上皮细胞氧化损伤水平,增加SOD清除氧自由基的活性,下调活化的Caspase-3和PARP蛋白表达.     

不同营养方式对肠道缺血再灌注大鼠肠屏障功能的影响

目的探讨不同营养物质及支持途径对肠道缺血再灌注大鼠肠屏障功能和细菌易位的影响。方法60只雄性SD大鼠建立肠道缺血再灌注模型,随机分成普通肠外营养组(PN),富含谷氨酰胺的肠外营养组(G-PN),普通肠内营养组(EN)及免疫增强型肠内营养组(IEN)。从术后第1天起连续营养支持7d,各组等氮、等热卡。观察肠道形态学、肠道黏膜通透性、肠道细菌易位情况和血浆内毒素水平及肠道免疫功能检测。结果PN组肠黏膜明显萎缩,其绒毛高度、黏膜厚度、隐窝深度及绒毛表面积均显著低于其他各组(P<0.05);其肠黏膜通透性及内毒素值显著高于其他各组(P<0.05),细菌易位率(100%)明显高于其他各组(G-PN组60.0%,EN组33.3%,IEN组20.0%)。PN组CD4 T淋巴细胞和IgA 浆细胞分布显著低于其他各组(P<0.01)。结论EN在维护肠黏膜屏障功能、防止细菌及内毒素易位方面优于PN。免疫增强型EN在维护肠黏膜屏障、改善肠道免疫功能、防止细菌易位方面作用优于普通EN。     

白藜芦醇对重症急性胰腺炎大鼠肠黏膜缺血-再灌注损伤的保护作用

目的 观察白藜芦醇对重症急性胰腺炎(SAP)大鼠肠黏膜组织中超氧化物歧化酶(SOD)、丙二醛(MDA)、细胞间黏附分子-1(ICAM-1)及血管细胞黏附分子-1(VCAM-1)变化规律的影响,探讨白藜芦醇对SAP大鼠肠黏膜缺血-再灌注损伤保护作用的可能机理.方法 将54只大鼠随机分为假手术组、SAP组及白藜芦醇治疗组3组,每组18只.应用逆行胰胆管穿刺注射牛磺胆酸钠制备大鼠SAP模型,白藜芦醇溶液于制模成功后5 min通过阴茎背静脉注射,于制模成功后3、6及12 h时分别取6只大鼠剖杀,观察各组大鼠回肠黏膜组织中SOD、MDA、ICAM-1、VCAM-1和组织学变化以及白藜芦醇对其的影响.结果 与假手术组比较,SAP组小肠组织中SOD活性在各时相均降低(P＜0.05),MDA水平均升高(P＜0.05),ICAM-1和VCAM-1的表达量均明显升高(P＜0.05);与SAP组比较,白藜芦醇治疗组中白藜芦醇可明显升高SOD活性(P＜0.05),降低MDA水平(P＜0.05),使ICAM-1和VCAM-1的表达量均明显降低(P＜0.05),同时白藜芦醇可减轻其组织病理损害.结论 氧自由基参与了SAP大鼠肠黏膜缺血-再灌注损伤的病理生理过程,白藜芦醇可提高SAP大鼠肠黏膜组织中SOD活性、降低MDA水平,抑制脂质过氧化反应,下调肠组织中ICAM-1和VCAM-1的表达量,从而在SAP时减少对肠黏膜上皮细胞的损伤,对肠黏膜缺血-再灌注损伤起保护作用.     

小鼠肠缺血再灌注时肠黏膜肥大细胞与肠道菌群的关系

目的:评价小鼠肠缺血再灌注时肠黏膜肥大细胞与肠道菌群的关系。方法:健康雄性C57BL/6小鼠48只,9～12周龄,体重20～25 g,采用随机数字表法分为4组( n＝12)：假手术组(Sham组)、假手术+肥大细胞膜稳定剂色甘酸钠组(Sham+CS组)、肠缺血再灌注组(I/R组)和肠缺血再灌注+色甘酸钠组(...     

小剂量氯胺酮预处理对大鼠肠缺血再灌注损伤的影响

目的 探讨小剂量氯胺酮预处理对大鼠肠缺血再灌注损伤的影响.方法 清洁级健康雄性SD大鼠48只,体重230～270 g,随机分为6组(n=8):假手术组(S组)、氯胺酮+假手术组(KS组)、肠缺血再灌注组(I/R组)、氯胺酮预处理组(K组)、锌原卟啉Ⅸ+氯胺酮预处理组(KZ组)和锌原卟啉Ⅸ组(Z组).采用夹闭肠系膜上动脉根部1 h后再灌注的方法 制备肠缺血再灌注模型.于麻醉前30 min时,S组腹腔注射生理盐水2 ml,K组和KS组均腹腔注射氯胺酮10 mg/kg,KZ组依次腹腔注射氯胺酮10 ms/kg和锌原卟啉Ⅸ5 mg/kg,Z组腹腔注射锌原卟啉Ⅸ5 mg/kg.S组、KS组仅分离肠系膜上动脉,不结扎.于再灌注6 h时处死大鼠,取肠组织测定丙二醛(MDA)含量和超氧化物歧化酶(SOD)活性、血红素加氧酶-1(HO-1)及诱导型一氧化氮合酶(iNOS)的表达,光镜下观察肠组织病理学结果 并采用Chiu评分评价损伤程度.结果 与S组比较,I/R组、KZ组和Z组肠组织MDA含量升高,SOD活性降低,K组MDA含量升高(P<0.05或0.01),SOD活性差异无统计学意义(P>0.05),I/R组、K组、KZ组和Z组肠组织HO-1和iNOS表达上调(P<0.05或0.01),肠组织病理学损伤加重;与I/R组比较,K组肠组织MDA含量降低,SOD活性升高,肠组织HO-1表达上调,iNOS表达下调(P<0.05),肠组织病理学损伤减轻,KZ组和Z组以上指标差异无统计学意义(P>0.05).结论 小剂量氯胺酮预处理可减轻大鼠肠缺血再灌注损伤,可能与氯胺酮上调肠组织HO-1表达,下调iNOS表达有关.     

缺血预处理-后处理对大鼠肠缺血再灌注损伤的影响

目的 评价缺血预处理.后处理对大鼠肠缺血再灌注损伤的影响.方法 清洁级成年雄性SD大鼠40只.体重225～275 g,随机分为5组(n=8):假手术组(S组)仅分离肠系膜上动脉(SMA),不夹闭;肠缺血再灌注组(IIR组)采用夹闭SMA 60 min,再灌注60 min的方法制备肠缺血再灌注损伤模型;缺血预处理组(IPr组)夹闭SMA 10 min,再灌注10 min,余同IIR组;缺血后处理组(IPo 组)夹闭SMA 60 min后,再灌注30 s,缺血30 s,反复3次,再灌注60 min;缺血预处理.后处理组(IPr-IPo组)先行缺血预处理,再行缺血后处理,操作过程同IPr组和IPo组.于再灌注60 min时各组取肠粘膜组织,观察肠粘膜形态并行Chiu评分,检测丙二醛(MDA)含量,超氧化物歧化酶(SOD)及髓过氧化物酶(MPO)活性,同时采集动脉血样检测血浆肿瘤坏死因子α(TNF-α)及白细胞介素6(IL-6)浓度.结果 与S组比较,其余各组Chiu评分、MDA含量、MPO活性、血浆TNF-α与IL-6浓度升高,SOD活性降低(P<0.05).与IIR组比较,IPr组、IPo组及IPr-IPo组Chiu评分、MDA含量、MPO活性、血浆TNF-α和IL-6浓度降低.SOD活性升高(P<0.01).与IPr组和IPo组比较,IPr-IPo组Chiu评分和MDA含量降低,SOD活性升高(P<0.05).IPr组与IPo组各指标比较差异无统计学意义(P>0.05).结论 缺血预处理-后处理可减轻大鼠肠缺血再灌注损伤,较单独应用时效果好.     

缺血预处理-后处理对大鼠肠缺血再灌注损伤的影响

Objective To evaluate the effects of ischemic preconditioning-postconditioning on the intestinal ischemia-reperfusion (IR) injury in rats. Methods Forty healthy male SD weighing 225-275 g were randomly assigned into 5 groups ( n = 8 each): group I sham operation (group S) ; group II intestinal IR (group IIR); group Ⅲ ischemic preconditioning (group Ipr); group IV ischemic postconditioning (group Ipo); group V Ipr+ Ipo. The rats were anesthetized with intraperitonel 20% urethane 5 ml/kg. Superior mesenteric artery (SMA) was occluded for 60 min followed by 60 min reperfusion. In group S, SMA was isolated but not occluded. In group Ipr, SMA was occluded for 10 min followed by 10 min reperfusion, and the rest procedures were performed using the method described in group IIR. In group Ipo, 60 min ischemia was followed by three 30 s episodes of ischemia at 30 s intervals for reperfusion. In group Ipr+ Ipo, Ipr was performed followed by Ipo and the procedures were performed using the methods described in group Ipr and Ipo. The animals were killed at 60 min of reperfusion. The intestinal tissues were immediately removed for determination of MDA content, SOD and MPO activities and the degree of damage to intestinal mucous membrane was scored according to Chiu score. Arterial blood samples were taken for determination of plasma concentrations of TNF-α and 1L-6. Results Compared with group S, Chiu score, MDA content, MPO activity, and plasma concentrations of TNF-α and IL-6 were significantly increased, whereas SOD activity decreased in the other 4 groups ( P < 0.05). Chiu score, MDA content, MPO activity, and plasma concentrations of TNF-α and IL-6 were significantly decreased, whereas SOD activity increased in group Ipr, Ipo and Ipr + Ipo as compared with group IIR ( P < 0.05). Chiu score and MDA content were significantly lower, whereas SOD activity higher in group Ipr + Ipo than in group Ipr and Ipo ( P < 0.05). No significant differences were detected in the indices between group Ipr and group Ipo ( P > 0.05). Conclusion Ischemic preconditioning-postconditioning can attenuate the intestinal IR injury in rats, and the efficacy is better than that of either Ipr or Ipo alone.     

硫化氢对大鼠肝缺血再灌注损伤的影响

目的 评价硫化氢对大鼠肝缺血再灌注损伤的影响.方法 健康雄性SD大鼠30只,体重220～250 g,采用随机数字表法,将其随机分为假手术组(S组)、缺血再灌注组(IR组)和不同剂量硫化氢组(H2S1～3组),每组6只.S组仅暴露肝门,不夹闭动、静脉;IR组采用夹闭左、中叶肝蒂、门静脉和肝动脉支1h恢复灌注的方法制备大鼠肝缺血再灌注模型;H2S1～3组于再灌注前5min分别腹腔注射14、28、56 μmol/kg硫化氢钠.于再灌注6h时抽取下腔静脉血样并取肝组织,采用全自动生化分析仪测定血清谷丙转氨酶(ALT)和谷草转氨酶(AST)活性,采用二硫代二硝基苯甲酸法测定肝组织谷胱甘肽(GSH)含量,光镜下观察肝组织病理学结果.结果 与S组相比,IR组血清ALT和AST活性升高,肝组织GSH含量下降(P＜0.05);与IR组相比,H2S1～3组ALT和AST活性降低,肝组织GSH含量升高(P＜0.05);H2S1～3组肝病理学损伤较IR组明显减轻.结论 H2S可减轻大鼠肝缺血再灌注损伤.     

Role of intestinal bifidobacteria in the pathogenesis of gut-derived bacteria/endotoxin translocation and the effect of bifidobacterial supplement on gut barrier function following burns

Early multiple organ dysfunction syndrome appears to be facilitated with bacterial translocation in severely burn injury, yet the mechanisms of bacterial translocation remains in dispute. The aim of this study was to investigate the potential role of intestinal bifidobacteria in the pathogenesis of gut-derived bacteria/endotoxin translocation following burns and the effects of bifidobacterial supplement on gut barrier. Methods: Wistar rats were randomly divided into burn group (Burn, n=60),sham burn group (SB, n=10) in experiment Ⅰ , and burn + saline group (BS, n=30), burn + bifidobacteria group (BB, n=30), and sham-burn + saline group (SS, n= 10) in experiment Ⅱ. Animals in BB group were fed bifidobacterial preparation (5 × 109 CFU/ml) after burns, 1.5ml,twice daily. Animals in BS and SS were fed saline. Samples were taken on days 1, 3, and 5 in burn groups, and on day 3 in sham-burn groups. The incidence of bacteria/endotoxin translocation and counts of Bifidobacterium, Fungi and Escherichia coli in gut mucosa were determined with standard methods. The levels of sIgA in mucus of small intestine were measured by RIA. The positive sIgA expression in lamina propria and ileum mucosal injury was evaluated light microscopically by blinded examiners. Results: Our results showed that the incidence of bacterial translocation was increased after burns, which was accompanied by significant decrease in number of bifidobacteria but significant increase in E. coli and fungi in gut mucosa, and elevation of levels of plasma endotoxin and IL-6 (P<0. 001).The incidence of bacterial translocation was markedly reduced after 3- and 5-day supplementation of bifidobacteria compared with control group (P<0.05). The counts of mucosal bifidobacteria were increased by 4- to 40-fold,while E. coli and fungi were decreased by 2- to 30-fold and 10- to 150-fold, respectively, after bifidobacterial supplementation in contrast to control group. The damage of mucosa tended to be less pronounced after 3-day bifidobacteria-supplemented formula compared with control group [grade 2(0-6) vs. grade 4(3-6), P<0.05]. Moreover, the expression and release of sIgA was markedly augmented after 3-day bifidobacteria-supplementation formula and it returned to normal range on day 5. Conclusion: The decrease in counts and proportion of bifidobacteria in mucous membrane flora may play an important role in the development of bacteria/endotoxin translocation following thermal injury. The supplement of exogenous bifidobacteria could per se improve gut barriers, and attenuate bacteria/endotoxin translocation secondary to major burns.     

异丙酚对大鼠肠缺血再灌注时肠粘膜细胞凋亡的影响

目的评价异丙酚对大鼠肠缺血再灌注（I／R）时肠粘膜细胞凋亡的影响。方法24只SD大鼠随机分为3组（n=8），假手术组（S组）仅分离肠系膜上动脉（SMA）；肠缺血再灌注组（I／R组）阻断SMA1h；异丙酚组（P组）阻断SMA前30min腹腔注射异丙酚100mg／kg。于再灌注3h处死大鼠，取回肠末端组织，电镜及TUNEL法观察肠粘膜上皮细胞凋亡情况，并计算肠粘膜上皮细胞凋亡指数；测定肠粘膜超氧化物歧化酶（SOD）活性、丙二醛（MDA）及神经酰胺（CER）含量，RT-PCR法测定肠粘膜鞘磷脂酶（SMase）mRNA表达。结果与S组比较，I／R组肠粘膜SOD活性降低，MDA含量、CER含量、肠粘膜上皮细胞凋亡指数及SMasemRNA表达升高（P〈0．05或0．01）；与I／R组比较，P组MDA含量、CER含量、肠粘膜上皮细胞凋亡指数及SMasemRNA表达降低，S01）活性升高（P〈0．05或O．01）。I／R组肠粘膜SOD活性与CER含量呈负相关（r＝-0．775，P〈0．01），肠粘膜上皮细胞凋亡指数与CER含量呈正相关（r=0．852，P〈0．01）；P组肠粘膜上皮细胞凋亡指数与CER含量呈正相关（r=0．782，P〈0．01）。结论异丙酚可抑制大鼠肠缺血再灌注时肠粘膜上皮细胞凋亡，可能与清除氧自由基、下调SMasemRNA表达、减少CER生成有关。     

不同剂量磷酸肌酸钠预先给药对大鼠肝缺血再灌注损伤的影响

目的 评价不同剂量磷酸肌酸钠预先给药对大鼠肝缺血再灌注损伤的影响.方法 健康雄性SD大鼠30只,体重200～250 g,采用随机数字表法分为5组(n=6):假手术组(S组)、缺血再灌注组(I/R组)、不同剂量磷酸肌酸钠预先给药组(P1～3组).采用阻断肝左中动脉及其门静脉90 min恢复灌注的方法制备大鼠肝缺血再灌注模型.P1-3组于缺血前60 min时分别尾静脉注射磷酸肌酸钠50、150和4S0mg/kg.S组和I/R组给予等容量生理盐水.于再灌注4h时采集腹主动脉血样,测定血浆ALT、AST、TNF-α和IL-1β水平.取肝组织,采用ELISA法检测MPO活性,免疫组化法检测细胞间粘附分子(ICAM-1)的表达水平,TUNEL法检测肝细胞凋亡数,电镜下观察病理学结果.结果 与S组比较,I/R组和P1～3组肝组织MPO、血浆ALT、AST活性及TNF-α、IL-1β浓度、肝细胞凋亡数升高(P＜0.05);与I/R组比较,P1～3组上述指标降低(P＜0.05);P1～3组上述指标依次降低(P＜0.05).结论 磷酸肌酸钠预先给药可呈剂量依赖性地减轻大鼠肝缺血再灌注损伤,其机制与抑制炎性反应有关.     

异丙酚联合白藜芦醇预先给药对大鼠肝脏缺血再灌注损伤的影响

目的 评价异丙酚联合白藜芦醇预先给药对大鼠肝脏缺血再灌注损伤的影响.方法 健康成年雄性SD大鼠108只,体重220 ～ 270 g,6～7周龄,采用随机数字表法,将其分为6组(n=18):假手术组(S组)、缺血再灌注组(I/R组)、溶剂组(TW-80组)、异丙酚组(P组)、白藜芦醇组(R组)和异丙酚+白藜芦醇组(P+R组).采用阻断第一肝门30 min后恢复灌注的方法制备大鼠肝脏缺血再灌注模型.于缺血前10 min经股静脉给药,P组静脉输注异丙酚10 mg·kg-1·h-1至术毕;R组静脉注射白藜芦醇10 mg/kg;P+R组静脉注射白藜芦醇10 mg/kg后输注异丙酚10 mg·kg1·h-1至术毕;S组和I/R组以等容量生理盐水替代,TW-80组静脉输注等容量TW-80.于再灌注3、6、12h时经上下腔静脉取血样2 ml,测定血清ALT、AST活性,取肝组织,测定SOD、髓过氧化物酶(MPO)活性、诱导型一氧化氮合酶(iNOS)表达、MDA和一氧化氮(N0)含量,观察肝组织病理学改变.结果 与S组比较,其余各组血清ALT、AST活性、肝组织MDA、NO含量、MPO活性和iNOS表达水平升高,SOD活性降低(P＜0.05).与I/R组比较,P组、R组及P+R组血清ALT、AST活性、肝组织MDA、NO含量、MPO活性和iNOS表达水平降低,SOD活性升高(P＜0.05),TW-80组上述各指标差异无统计学意义(P＞0.05).与P组和R组比较,P+R组肝组织SOD活性升高,其余指标均明显降低(P＜0.05).P组、R组及P+R组肝组织病理学损伤程度轻于I/R组.结论 异丙酚联合白藜芦醇预先给药可减轻大鼠肝脏缺血再灌注损伤,其效果优于两者单独应用;机制与提高机体抗氧化能力,抑制脂质过氧化反应,减少内源性NO生成有关.     

Effects of two fluid resuscitations on the bacterial translocation and inflammatory response of small intestine in rats with hemorrhagic shock

Objective： To investigate the effects of two fluid resuscitations on the bacterial translocation and the inflammatory factors of small intestine in rats with hemorrhagic shock. Methods： Fifty SD healthy male rats were randomly divided into 5 groups （ n = 10 per group） ： Group A （ Sham group）, Group B （ Ringer＇ s solution for 1 h ）, Group C （Ringer＇ s solution for 24 h ）, Group D （ hydroxyethyl starch for 1 h ） and Group E （（ hydroxyethyl starch for 24 h）. A model of rats with hemorrhagic shock was established. The bacterial translocation in liver, content of tumor necrosis factor-α （TNF-α） and changes of myeloperoxidase enzyme （MPO） activities in small intestine were pathologically investigated after these two fluid resuscitations, respectively. Results ： The bacterial translocation and the expression of TNF-α in the small intestine were detected at 1 h and 24 h after fluid resuscitation. There were significant increase in the number of translocated bacteria, TNF-α and MPO activities in Group C compared with Group B, significant decrease in Group E compared with Group D and in Group B compared with Group D. The number of translocated bacteria and TNF-α expression significantly decreased in Group E as compared with Group C. Conclusions： The bacterial translocation and the expression of TNF-α in the small intestine exist 24 h after fluid resuscitation. 6 % hydroxyethyl starch can improve the intestinal mucosa barrier function better than the Ringer＇ s solution.     

齐墩果酸预先给药对大鼠肝脏缺血再灌注损伤的影响

目的 探讨齐墩果酸预先给药对大鼠肝脏缺血再灌注损伤的影响.方法 清洁级健康雄性SD大鼠128只,体重230～250 g,随机分为4组(n=32):假手术组(S组)、缺血再灌注组(IR组)、羧甲基纤维素钠组(CMC组)和齐墩果酸预处理组(OA组).OA组胃内灌注齐墩果酸混悬液100 mg/kg,CMC组以相同容积的0.5%羧甲基纤维素钠溶液、S组与IR组以相同容积的饮用水替代,每天1次,连续7 d,第8天时IR组、CMC组和OA组采用阻断门静脉及肝动脉分支60 min后再灌注的方法制备肝脏缺血再灌注模型,S组仅分离胆管及门静脉、肝动脉分支.于再灌注即刻、3、6和12 h时取下腔静脉血样,测定血清ALT活性;取左肝中叶组织,测定SOD活性、MDA和谷胱甘肽(GSH)含量和磷酸化磷脂酰肌醇-3激酶(p-PI3K)、蛋白质丝氨酸苏氨酸激酶(Akt)、p-Akt、Bcl-2、Bax、p-Bad和Bad的表达水平,观察肝组织病理学结果.结果 与S组比较,IR组、CMC组和OA组再灌注期间血清ALT活性和肝组织MDA含量升高,肝组织SOD活性和GSH含量降低,p-PI3K、p-Akt、Bax、Bad、p-Bad表达上调,Bcl-2表达下调(P＜0.05);与IR组比较,OA组再灌注期间血清ALT活性和肝组织MDA含量降低,肝组织SOD活性和GSH含量升高,p-PIK、p-Akt、Bcl-2和p-Bad表达上调,Bad和Bax表达下调(P＜0.05),CMC组上述指标差异无统计学意义(P＞0.05);与CMC组比较,OA组再灌注期间血清ALT活性和肝组织MDA含量降低,肝组织SOD活性和GSH含量升高,p-PI3K、p-Akt、Bcl-2和p-Bad表达上调,Bad和Bax表达下调(P＜0.05).OA组肝组织病理学损伤较IR组减轻.结论 齐墩果酸预先给药可减轻大鼠肝脏缺血再灌注损伤,其机制可能与激活PI3K/Akt信号通路,抑制细胞凋亡有关.     

天然蒙脱石防治烧伤后肠道细菌移位的实验研究

目的　探讨天然蒙脱石对烧伤大鼠肠道细菌移位的防治作用。　方法　SD大鼠54只,分为正常对照组6只、烧伤对照组与烧伤治疗组各24只。后两组大鼠预先喂服转染了质粒pUC19的示踪菌JM109,证实质粒已定植于其肠道后,制成30%TBSAⅢ度烫伤(以下称烧伤)模型。烧伤治疗组大鼠伤后立即喂服天然蒙脱石0. 6g d-1 kg-1,烧伤对照组大鼠不喂服药物。观察正常对照组大鼠以及烧伤对照组、烧伤治疗组大鼠伤后12h和1、3、5d血液、肠系膜淋巴结细菌移位情况,并行酶切鉴定;检测大鼠肠组织丙二醛(MDA)及超氧化物歧化酶(SOD)的含量;用病理学方法观察整段小肠的损伤情况,测量空肠黏膜绒毛高度并计算基底膜细胞核分裂相。　结果　血液细菌培养:伤后1、5d,烧伤对照组阳性鼠数多于正常对照组,烧伤治疗组阳性鼠数少于烧伤对照组(P<0 05).肠系膜淋巴结细菌定量:烧伤治疗组伤后1、5d为(38±16)、(68±20)集落形成单位(CFU) /g;烧伤对照组伤后1、5d为( 228±67 )、( 183±29 )CFU/g,明显高于前者(P<0. 01 ).MDA、SOD含量:烧伤治疗组与烧伤对照组伤后各时相点比较,差异有统计学意义(P<0. 05).烧伤治疗组大鼠伤后各时相点空肠绒毛高度及基底膜细胞核分裂相明显高于或多于烧伤对照组(P<0. 05或0. 01)。　结论　天然蒙脱石对严重烧伤大鼠肠     

人重组生长激素对梗阻性黄疸大鼠肠源性细菌/内毒素移位的影响

目的探讨人重组生长激素(rhGH)减轻梗阻性黄疸时肠源性细菌及内毒素移位的作用及机制。方法Wister大鼠42只分为3组假手术组(SO组)、胆总管结扎组(BDL组)及rhGH治疗组(rhGH组)。实验1周后检测各组肝功指标的变化及血浆内毒素水平,取肝、肾、肠系膜淋巴结等肠道外器官组织做细菌培养,电镜观察末端回肠黏膜变化。结果rhGH组多项肝功指标较BDL组明显改善,rhGH组血浆内毒素水平为(0·38±0·03)EU/ml,较BDL组的(0·65±0·04)EU/ml明显降低(P<0·01),与SO组的(0·30±0·02)EU/ml比较无显著差异(P>0·05)。BDL组肝、肾、肠系膜淋巴结中细菌移位率高于另两组,其中肠系膜淋巴结细菌移位率为64·29%,明显高于SO组及rhGH组(P<0·05),后两组之间各部位细菌检出率差别无显著性(P>0·05)。电镜显示BDL组肠黏膜上皮细胞坏死,细胞核固缩,线粒体肿胀变性,内质网明显扩张。rhGH组肠黏膜上皮改变较BDL组明显减轻,接近SO组所见。结论应用rhGH可保护梗阻性黄疸时小肠黏膜屏障功能,减少肠源性细菌/内毒素移位的发生。