内毒素血症大鼠肠道传输改变及一氧化氮作用

目的 探讨内毒素血症状态与肠道传输改变及一氧化氮变化,为多器官功能衰竭的发生提供理论依据。方法 １０４只雄性Ｗｉｓｔａｒ大鼠,随机分为对照组和内毒素血症组：肠道伟输速度研究采用腹腔注射ＬＰＳ １０ｍｇ／ｋｇ;观察内毒素血症肌间神经丛,以及空肠免疫组化染色显示ＮＯＳⅡ阳性神经在肠道分布及骨毒素血症后的变化。结果 内毒素血症后小肠传输速度加快,内毒素血症３、６、１２小时血浆ＮＯ、空肠ＮＯＳ活性（ｉＮＯ     

一氧化氮对内毒素血症大鼠肠道的保护作用

用一氧化氮（ＮＯ）合酶底物左旋精氨酸和其特异性抑制剂硝基左旋精氨酸对比观察两者对内毒素血症大鼠肠道损伤的影响。结果表明抑制ＮＯ合成可加重内毒素引起的肠道微血管损伤和肠粘膜上皮损害，而促进ＮＯ合成则可减轻上述改变。提示在本实验条件下，ＮＯ对内毒素血症大鼠的肠道损伤有一定的保护作用。     

急性胰腺炎与肠屏障损伤、细菌移位及内毒素血症

胰腺炎是常见的急腹症之一，自1901年Opie提出共同通道学说以来，胰酶激活、胰腺自身消化学说一直被认为是胰腺炎发病的经典机制。胰腺炎的治疗围绕着如何减少胰酶的产生、避免胰酶被激活而进行。然而这种治疗并未达到所希望的目的。重症胰腺炎患者往往死于继发的感染和脏器功能衰竭。显然传统的胰酶自身消化理论不能完全解释急性胰腺炎的病程发展和转归。     

PEG4000监测内毒素血症大鼠细菌移位的实验研究

目的:观察不同程度内毒素血症时血中PEG4000含量与细菌移位(bacterial translocation,BT)率,探讨血中聚乙二醇4000(polyethylene glycol 4000,PEG4000)含量与内毒素血症细菌移位率的关系.方法:建立大鼠PEG4000模型和内毒素血症模型,并根据内毒素(lipopolysaccharide,LPS)不同浓度分成三组(攻击0.1 mg/L LPS组,攻击1 mg/L LPS组和攻击5 mg/L LPS组.)另外设麻醉对照组及生理盐水注入组(对照组).分别测量各组大鼠血中PEG4000含量.取肠系膜淋巴结(mesenteric lymph nodes,MLN)进行细菌培养,并计算细菌移位率.结果:攻击组大鼠血PEG4000含量及细菌移位发生率比生理盐水注入组均明显升高,差异均有显著性.大鼠血LPS浓度和血PEG4000含量呈正相关.PEG4000含量与BT也有明显相关性(R2=0.823).结论:内毒素血症可引起肠黏膜通透性增高.肠通透性升高与BT率相关,PEG4000含量可监测细菌移位率.     

大鼠肠道缺血再灌注损伤后肠源性细菌/内毒素移位的初步研究

目的 观察肠道Ｉ／Ｒ损伤对肠源性细菌／内毒素移位的影响。方法 采用夹闭肠系膜前动脉（时间６０ｍｉｎ）技术复制肠道Ｉ／Ｒ损伤大鼠模型：（１）检测血浆内每素水平（鲎试剂定量试验法）和肿瘤坏死因子（ＴＮＦα）,（２）肠系膜淋巴结、肝、肺、肾组织交浆进行细菌培养。结果 研究成功地复制了肠道Ｉ／Ｒ损伤大鼠模型,并观察到大鼠肠道 伤可引起：（１）门、腔静脉血中内毒素水平明显升高（Ｐ均〈０．０１）,门脉血浆内毒     

胆汁酸对肝硬化大鼠肠道细菌移位和内毒素血症的影响

目的观察胆汁酸对肝硬化大鼠的肠道细菌移位和内毒素血症的影响。方法将37只肝硬化及30只健康大鼠均随机分为熊去氧胆酸组、甘氨胆酸组(均给予胆汁酸70mg·kg-1·d-1)及对照组(给予等量生理盐水)治疗2周。测定胆汁分泌速度、末端回肠细菌总数、细菌移位率及血浆内毒素水平。结果肝硬化大鼠胆汁分泌速度显著低于健康大鼠(P<0.01),给予胆汁酸治疗后,速度增至正常水平。肝硬化大鼠比健康大鼠的回肠细菌总量显著增高(P<0.01),而给予胆汁酸后则降至正常水平。给予胆汁酸的肝硬化大鼠细菌移位率及血浆内毒素水平均较肝硬化对照组显著降低(P<0.01),肝硬化大鼠熊去氧胆酸组和甘氨胆酸组间上述指标差别均无统计学意义(P>0.05)。结论给予肝硬化大鼠结合型或非结合型胆汁酸均可以增加胆汁分泌、抑制肠道细菌过度生长,减少细菌移位、内毒素血症的发生率。     

肝门阻断对大鼠肠道细菌移位和内毒素血症的影响

 【目的】 探讨大鼠肝门阻断后肠道细菌移位&#65380;内毒素血症情况及肝硬化模型肝门阻断后细菌移位特点&#65377;【方法】 将40只非肝硬化雄性SD大鼠及40只肝硬化模型雄性SD大鼠分别随机分为假手术组(n = 10)&#65380;肝门阻断10 min(n = 10)&#65380;20 min(n = 10)&#65380;30 min组(n = 10),在行肝门阻断手术24 h后分别取肠系膜淋巴结&#65380;肝&#65380;肺及门&#65380;腔静脉血作细菌培养,并取门&#65380;腔静脉血作内毒素检测&#65377;【结果】 非肝硬化大鼠肝门阻断30 min组门&#65380;腔静脉血内毒素浓度(EU/mL 0.18 ± 0.05&#65380;0.17 ± 0.06)明显高于假手术组(EU/mL 0.12 ± 0.03&#65380;0.11 ± 0.03),肠系膜淋巴结细菌培养呈阳性&#65377;肝硬化大鼠肝门阻断20 min组门&#65380;腔静脉血内毒素浓度(EU/mL 0.42 ± 0.09&#65380;0.35 ± 0.07)明显高于假手术组(EU/mL 0.15 ± 0.04&#65380;0.14 ± 0.03),并随肝门阻断时间延长升高越明显,肠系膜淋巴结&#65380;肝及门&#65380;腔静脉血细菌培养出现阳性,且随肝门阻断时间延长阳性率升高越明显,培养出阳性细菌主要为大肠杆菌&#65377;在肝门阻断20&#65380;30 min下肝硬化大鼠比非肝硬化大鼠门&#65380;腔静脉血内毒素浓度升高更明显(P < 0.01),出现细菌移位阳性率也更高&#65377;【结论】 大鼠肝门阻断后可导制内毒素血症及肠道细菌移位,这一病理过程在肝硬化情况下更容易出现,并且随肝门阻断时间延长而更加明显&#65377;     

大腹皮对肠道内毒素移位的影响

目的：探讨大腹皮对肠道内毒素移位的影响，为临床应用大腹皮提供理论依据。方法：30只Wistar大鼠随机分为大腹皮组、阿托品组及对照组，分别给大鼠灌服大腹皮水提液、阿托品或蒸馏水1h后，以葡聚糖蓝－2000为胃肠内标记物观察大鼠肠道传输的变化，同时测定血浆荧光内毒素的含量变化。结果：大腹皮组大鼠肠道传输显增强（P＜0．01），血浆荧光内毒素的含量显低于对照组（P＜0．01）；阿托品组肠道传 输显减弱（P＜0．01），血浆荧光内毒素的含量显高于对照组（P＜0．01）。结论：大腹皮可通过促进肠道传输减少肠道内毒素的移位。     

内毒素血症对糖尿病大鼠氧化应激及一氧化氮的影响

目的观察内毒素血症对糖尿病大鼠氧化应激及一氧化氮(NO)的影响。方法SD大鼠腹腔注射链脲佐菌素(STZ,50 mg/kg)建立糖尿病动物模型,在此基础上再以脂多糖(LPS,0.5 mg/kg)腹腔注射诱导内毒素血症模型,观察注射LPS后6 h、12 h、24 h及72 h各时间点血糖、胰岛素、氧化应激指标(SOD、MDA、GSH)及一氧化氮水平的变化。结果内毒素血症糖尿病大鼠血清NO水平显著升高,于注射LPS后24 h达峰值(P<0.05);而血清SOD、GSH水平却明显降低(P<0.05),MDA水平则明显升高(P<0.05),分别于注射LPS后24 h达峰值或谷值;注射LPS后的血糖(12、24、72 h)及胰岛素水平(24、72 h)变化有统计学意义。结论内毒素血症可显著降低糖尿病大鼠抗氧化应激能力,增加NO的生成,同时加重糖代谢紊乱。     

急性脊髓损伤后家兔肠道菌群移位和内毒血症的肠道病理生理机制

目的探讨家兔脊髓损伤后肠道菌群移位和内毒血症的肠道病理生理机制。方法建立兔脊髓损伤性截瘫模型,12只家兔行脊髓损伤前后胃肠道电生理和压力测定。另外24只家兔分为:正常对照组(6只)和实验组(18只),在无菌条件下,采集门静脉血进行内毒素定量测定和细菌培养,肠系膜淋巴结作细菌培养并鉴定。取实验组和对照组各动物的小肠、结肠行HE染色检查观察肠黏膜病理变化,小肠行电镜检查观察肠黏膜上皮细胞病理变化。结果脊髓损伤后,发现胃肠道生物电改变明显,以结肠为重。中远段结肠的蠕动明显减少,部分时段甚至消失。早期小肠和结肠黏膜下充血和黏膜上皮细胞水肿,随后,黏膜上皮间隙增宽,细胞崩解,导致肠黏膜屏障破坏。血清内毒素含量从24h就开始增高,到72h差异显著(P<0.05)。门静脉血与肠系膜淋巴结各阶段细菌培养阳性率均较高,无统计学差异(P>0.05)。结论急性脊髓损伤后,中远段结肠的蠕动功能障碍导致排便障碍、细菌过度增长与入侵、影响血运等一系列破坏因素而加速肠黏膜屏障破坏为肠道菌群移位和内毒血症的主要病理生理机制。     

口服谷氨酰胺对实验性肝硬化大鼠血浆内毒素及NO水平变化的影响

目的　观察口服谷氨酰胺 (Gln)对实验性肝硬化大鼠血浆内毒素及一氧化氮 (NO)水平变化的关系 ,探讨肝硬化内毒素血症和高动力循环状态的关系。方法　采用四氯化碳致大鼠肝硬化模型。 4 0只大鼠随机分为 2组 ,A组为肝硬化 +正常饮食组 ,B组为肝硬化 +Gln组。采用麦滋林颗粒 (含 99%谷氨酰胺 )灌胃 (每天 0 .6g kg)。采用鲎试剂与鲎三肽的偶氮显色法测定血浆内毒素含量 ,采用还原显色法测定血浆NO含量。结果　A组大鼠 9周与 1 2周内毒素与NO水平明显升高 ,P <0 .0 5。B组大鼠 9周与 1 2周上述指标降低 ,P <0 .0 5。结论　肝硬化时肠道的屏障功能受损 ,是导致内毒素血症及NO浓度增高的原因之一 ,而经口服谷氨酰胺后可以减轻内毒素血症 ,降低NO浓度。     

非洛地平对自发性高血压大鼠一氧化氮及诱导性一氧化氮合酶的影响

目的　观察非洛地平 (Felodipine)对自发性高血压大鼠一氧化氮 (NO)及诱导性一氧化氮合酶 (iNOS)的影响。方法　取自发性高血压大鼠 2 2只 ,随机分为生理盐水组、Felodipine正常剂量组及其低剂量组 ,每天灌胃一次 ,连续 15天 ,末次给药后摘眼球取血以及取动物脏器 ,分别测定血清NO和iNOS的含量。结果　灌胃 15天后 ,Felodipine正常剂量组的NO含量为 (12 7± 7 5 ) μmol/L ,与生理盐水组 (10 2 3± 4 6 ) μmol/L相比 ,差异有明显显著性 (P <0 0 1) ;Felodipine低剂量组NO含量为 (119± 8 3) μmol/L ,与生理盐水组相比 ,差异有显著性 (P <0 0 5 ) ,Felodipine正常剂量组的组织iNOS活性降低 ,为 1 17± 0 2 3,与生理盐水组 (2 2 5± 0 94 )相比 ,差异显著 (P <0 0 5 ) ,与Felodipine低剂量组 (1 76± 0 5 7)相比 ,差异亦显著 (P <0 0 5 )。结论　Felodipine组可有效地在降低血压的同时 ,提高血清NO的含量 ,并且对抗血压增高所造成的iNOS的活性增强 (或二者互为因果 )。     

Effects of lactulose on intestinal endotoxin and bacterial translocation in cirrhotic rats

Objective To investigate the effects of lactulose on intestinal bacterial overgrowth (IBO), bacterial translocation (BT), intestinal transit and permeability in cirrhotic rats.Methods BT in all animals was assessed by bacterial culture of mesenteric lymph node ( MLN), liver and spleen, and IBO was assessed by a jejunal bacterial count of the specific organism. Intestinal permeability was determined by the 24-hour urinary ^99mTc-diethylenetriamine pentaacetatic acid (^99mTc-DTPA) excretion, and intestinal transit was determined by measuring the distribution of ^51Cr in the intestine.Results BT and IBO were found in 48% and 80% of the cirrhotic rats, respectively, while not in the control rats. Cirrhotic rats with IBO had significantly higher levels of intestinal endotoxin higher rates of bacterial translocation, shorter intestinal transit time and higher intestinal permeability than those without IBO. It was also found that BT were closely associated with IBO and injury of the intestinal barrier. Compared with the placebo group, lactulose-treated rats had lower rates of BT and IBO,which were closely associated with increased intestinal transit and improved intestinal permeability by lactulose.Conclusions Our study indicate that endotoxin and bacterial translocation in cirrhotic rats may attribute to IBO and increased intestinal permeability. Lactulose that accelerates intestinal transit and improves intestinal permeability might be helpful in preventing intestinal bacterial and endotoxin translocation.     

不同潮气量机械通气对大鼠肺组织iNOS、NO的影响

目的 探讨诱导型一氧化氮合酶(iNOS)及一氧化氮(NO)在不同潮气量机械通气致大鼠急性肺损伤(VILI)中的作用. 方法 24只雄性Wistar大鼠随机分为对照组、小潮气量组和大潮气量组,每组各8只.用SABC免疫组化染色法检测肺组织iNOS蛋白表达,用逆转录—聚合酶链反应(RT-PCR)法检测肺组织iNOS mRNA表达,用硝酸还原酶法测定肺组织和血浆NO含量. 结果 与对照组和小潮气量组相比,大潮气量组大鼠肺组织iNOS mRNA及其蛋白表达水平以及肺组织和血浆NO含量均明显增JJU(均P<0.01);而小潮气量组与对照组各项指标比较差异无统计学意义(P>0.05). 结论 大潮气量机械通气可诱导肺组织iNOS mRNA及其蛋白高表达,产生大量内源性NO导致肺组织损伤,而小潮气量机械通气对正常肺组织无明显影响. 组化染色法检测肺组织iNOS蛋白表达,用逆转录一聚合酶链反应(RT-PCR)法检测肺组织iNOS mRNA表达,用硝酸还原酶法测定肺组织和血浆NO含量. 结果 与对照组和小潮气量组相比,大潮气量组大鼠肺组织iNOS mRNA及其蛋白表达水平以及肺组织和血浆NO含量均明显增JJU(均P<0.01) 而小潮气量组与对照组各项指标比较差异无统计学意义(P>0.05). 结论 大潮气量机械通气可诱导肺组织iNOS mRNA及其蛋白高表达,产生大量内源性NO导致肺组织损伤,而小潮气量机械通气对正常肺组织无     

Role of granulocyte colony-stimulating factor in paclitaxel-induced intestinal barrier breakdown and bacterial translocation in rats

Background  Chemotherapy causes breakdown of the intestinal barrier, which may lead to bacterial translocation. Paclitaxel, an anti-tubulin agent, has many side effects; however, its effect on the intestinal barrier is unknown. Previous studies show that granulocyte colony-stimulating factor (G-CSF) plays an important role in modulating intestinal barrier function, but these studies are not conclusive. Here, we investigated the effects of paclitaxel on the intestinal barrier, and whether G-CSF could prevent paclitaxel-induced bacterial translocation.

Methods  Twenty-four male Sprague-Dawley rats were divided into three groups: control group, paclitaxel group and paclitaxel + G-CSF group. Intestinal permeability was measured by the urinary excretion rates of lactulose and mannitol administered by gavage. The mesenteric lymph nodes, spleen and liver were aseptically harvested for bacterial culture. Endotoxin levels and white blood cell (WBC) counts were measured and bacterial quantification performed using relative real-time PCR. Jejunum samples were also obtained for histological observation. Intestinal apoptosis was evaluated using a fragmented DNA assay and terminal deoxynucleotidyl transferase-mediated deoxyuridine triphosphate (dUTP)-biotin nick end-labeling staining. One-way analysis of variance and Fisher’s exact test were used to compare differences between groups.

Results  Paclitaxel induced apoptosis in 12.5% of jejunum villus cells, which was reduced to 3.8% by G-CSF treatment. Apoptosis in the control group was 0.6%. Paclitaxel treatment also resulted in villus atrophy, increased intestinal permeability and a reduction in the WBC count. G-CSF treatment resulted in increased villus height and returned WBC counts to normal levels. No bacterial translocation was detected in the control group, whereas 6/8, 8/8, and 8/8 rats in the paclitaxel group were culture-positive in the liver, spleen and mesenteric lymph nodes, respectively. Bacterial translocation was partially inhibited by G-CSF.

Conclusions  Paclitaxel disrupts the intestinal barrier, resulting in bacterial translocation. G-CSF treatment protects the intestinal barrier, prevents bacterial translocation, and attenuates paclitaxel-induced intestinal side-effects.

     

肠缺血再灌注对大鼠肺组织一氧化氮及一氧化氮合酶的影响

目的：观察大鼠肠缺血再灌注后肺泡巨噬细胞活化分泌ＮＯ及肺组织内ＮＯＳ的变化。方法：建立实验大鼠肠缺血再灌注模型,采用Ｇｒｉｅｓｓ法和分光光度法分别测定肺组织内ＮＯ及ＮＯＳ的活性。结果：肠血再灌注组肺泡巨噬细胞分泌ＮＯ的水平及肺内ＮＯＳ的水平均显著高于假手术对照组。结论：肠缺血再灌注后肺内巨噬细胞的ｉＮＯＳ被激活,大量合成并释放ＮＯ,其作用一方面可增强杀菌功能,另一方面导致肺组织损伤。     

神经元型一氧化氮合酶的核转位现象

目的：研究神经元型一氧化氮合酶（neuronal nitric oxide synthase,nNOS）的亚细胞分布。方法：以体外培养的大鼠星形胶质细胞以及神经细胞株PC12、R2为研究对象,应用共聚焦激光扫描显微镜及Western Blotting技术检测nNOS的亚细胞分布。结果：次传代后的前6天,nNOS主要分布于星形胶质细胞的细胞质内,细胞核内几乎没有分布。在次传代后的第7天,nNOS主要分布于细胞核内,且持续时间近10 h。此后,nNOS又主要分布于细胞质内。然而,在神经细胞株PC12、R2没有发生nNOS核转位.结论：在一定的体外培养时间,星形胶质细胞发生nNOS核转位,并且nNOS核转位是原代培养神经细胞特有的一种生物学行为。     

Effects of lactulose on intestinal endotoxin and bacterial translocation

Objective To investigate the effects of lactulose on intestinal bacterial overgrowth (IBO), bacterial translocation (BT), intestinal transit and permeability in cirrhotic rats.
Methods BT in all animals was assessed by bacterial culture of mesenteric lymph node (MLN), liver and spleen, and IBO was assessed by a jejunal bacterial count of the specific organism. Intestinal permeability was determined by the 24-hour urinary 99mTc-diethylenetriaminepentaacetate (99mTc-DTPA) excretion, and intestinal transit was determined by measuring the distribution of 51Cr in the intestine.
Results BT and IBO were found in 48% and 80% of the cirrhotic rats, respectively, while not in the control rats. Cirrhotic rats with IBO had significantly higher levels of intestinal endotoxin higher rates of bacterial translocation, shorter intestinal transit time and higher intestinal permeability than those without IBO. It was also found that BT was closely associated with IBO and injury of the intestinal barrier. Compared with the placebo group, lactulose-treated rats had lower rates of BT and IBO, which was closely associated with increased intestinal transit and improved intestinal permeability by lactulose.
Conclusions Our study indicate that endotoxin and bacterial translocation in cirrhotic rats may attribute to IBO and increased intestinal permeability. Lactulose that accelerates intestinal transit and improves intestinal permeability might be helpful in preventing intestinal bacterial and endotoxin translocation.     

乌司他丁对梗阻性黄疸肠粘膜屏障功能影响的实验研究

目的 探讨梗阻性黄疸对肠粘膜屏障功能的影响及乌司他丁(UTI)的保护作用.方法 取雄性SD大鼠72只,随机均分为假手术组(A组)、梗阻性黄疸组(B组)、UTI干预组(C组),每组又分术后3、5、7、10 d4个时相.采用胆总管结扎法建立梗阻性黄疸模型.C组从术后第1天始每天腹腔注射UTI 40 000IU/kg,A组和B组用等量生理盐水作对照.检测各时相肝功能,血浆内毒素,取肠系膜淋巴结、肝、脾组织行细菌培养,光镜观察末端回肠粘膜形态改变,并用病理图像分析系统测量肠绒毛高度及粘膜厚度.结果 各时相肝功能指标、血浆内毒素B组较A组升高(P＜0.01);C组较B组降低(P＜0.01);血浆内毒素C组较A组术后3 d时相差异无统计学意义(P＞0.05).细菌移位率B组较A组升高(P＜0.01);C组较B组降低(P＜0.05);C组与A组相比,差异无统计学意义(P＞0.05).B组术后第3天即见肠粘膜受损改变,随时间推移进行性加重;C组较B组肠粘膜损害明显减轻.B组各时相小肠绒毛高度、粘膜厚度均低于A组(P＜0.01);C组则较B组升高(P＜0.01或P＜0.05);C组较A组术后3 d时相差异无统计学意义(P＞0.05).结论 梗阻性黄疸早期即可导致肠粘膜屏障功能受损,且随时间延长进行性加重;UTI对梗阻性黄疸时受损的肠粘膜屏障功能具有保护作用,对早期病变效果更好.