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.     

微生态制剂对肝硬化大鼠肠道细菌过度生长及肠道细菌易位的影响

目的 观察肝硬化大鼠肠道细菌过度生长及细菌易位情况,研究微生态制剂对其影响.方法 皮下注射40?l4橄榄油溶液诱导大鼠肝硬化模型,微生态制剂治疗.随机分成正常对照组(13只)、肝硬化模型组(10只)、肝硬化益生元治疗组(19只)、肝硬化益生菌治疗组(19只)及肝硬化治疗对照组(20只)5组.检测各组大鼠肠杆菌计数、血清内毒素,无菌操作取肠系膜淋巴结、肝、脾组织分别进行细菌培养观察细菌易位情况.结果 ①肝硬化模型组大鼠小肠内肠杆菌计数较正常组明显增多(P＜0.01);内毒素血症的阳性率及细菌易位率明显高于正常组(P＜0.01);②益生元治疗组肠杆菌计数较肝硬化治疗对照组明显降低(P＜0.05).益生元和益生菌治疗组内毒素血症的阳性率及细菌易位率均较肝硬化治疗对照组降低(P＜0.05),但二者之间无明显差异.结论 ①肝硬化大鼠存在小肠内肠杆菌明显过度生长,内毒素血症阳性率及细菌易位率明显高于正常组;②益生元和益生菌在治疗肝硬化大鼠内毒素血症及防止肠道细菌易位方面有明显疗效;③益生元对肝硬化大鼠肠杆菌过度生长有抑制作用.     

肝创伤时细菌移位及小肠Fas表达的实验研究

目的 研究肝外伤时小肠肠粘膜屏蔽损伤、细菌移位和Fas表达意义。方法 对肝损伤后不同时间进行血中IL－6、TNF、NO、内毒素、肠粘膜通透性的测定以及荧光标记菌示踪、组织学形态学及Fas免疫组化等观察。结果 肝创伤后血中IL－6、TNF、NO升高，内毒素、肠粘膜通透性、荧光标记菌总阳性率均升高；组织学可见损伤，并可见Fas表达的增加。结论 在肝损伤时可引起肠粘膜屏障损伤和细菌移位，肠道是闭合性肝外伤腹腔感染的重要来源。Fas表达增加可能与肠粘膜屏障损伤相关。     

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.     

乳果糖对门脉高压大鼠肠粘膜屏障功能保护作用的研究

目的探讨乳果糖对肝硬化门脉高压大鼠肠粘膜屏障功能的保护作用。方法50只雄性SD大鼠皮下注射50%CCl4橄榄油溶液,制造门脉高压模型。造模后存活大鼠随机分为：（1）治疗组;（2）对照组;（3）模型组。治疗组即乳果糖组,灌服乳果糖5mL/kg,每日2次,直至大鼠排稀便（共10d）;对照组仅灌服葡萄糖水。11d后处死取全血及肝、脾、肾、和肠系膜淋巴结组织匀浆后作细菌培养,测细菌易位率;采用改良的偶氮基质显色法行内毒素测定;取回肠粘膜组织行HE、Masson染色和超微病理的观察研究;采用免疫组织化学方法测定回肠末端紧密连接蛋白（occludin）表达水平。结果治疗组细菌易位发生率较对照组和模型组均明显降低（P〈0.05）;与模型组、对照组比较,治疗组肝功能显著改善（P〈0.01）;治疗组血清内毒素水平（0.20±0.08）Eu/mL亦明显低于对照组、模型组之（0.33±0.06）Eu/mL、（0.44±0.07）Eu/mL（P〈0.01）;紧密连接蛋白的表达,治疗组与对照组、模型组比较,亦具有显著性差异（P〈0.01）。结论口服乳果糖可以改善肠道屏障功能,减少门脉高压大鼠肠道菌群易位,减轻内毒素血症,从而一定程度上改善肝功能。     

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.

     

小儿先天性心脏病术后肠道通透性的研究

目的 心脏手术中体外循环（extracorporeal circulation,ECC）的运用可引起肠道细胞的缺血缺氧,导致营养吸收障碍和肠粘膜屏障受损,缺血状态下肠道上皮通透性的增加早于肠道粘膜形态学的改变,所以测定肠道通透性的改变可反应先心病术后早期肠粘膜屏障功能的损伤.方法 选取先天性心脏病患儿10名,除外肠道病变和感染性疾病.分别于术前、术后24h、术后96h测定肠道通透性和血中内毒素浓度.采用高效液相色谱分析法（HPLC）测定尿中乳果糖（L）和甘露醇（M）的排泄比率（L/M）作为测定肠道通透性的指标,采取静脉血利用鲎试剂与合成基质（鲎三肽）的偶氮显色法来测定样品中微量的内毒素浓度.结果 先天性心脏病患儿手术后24 h肠道通透性增加（P＜0.01）,血中内毒素浓度较术前上升（P＜0.01）,术后96 h肠道通透性恢复,而血中内毒素仍维持在较高水平（P＜0.05）.结论 小儿先天性心脏病术后肠道通透性增高,并出现内毒素血症.     

梗阻性黄疸对大鼠肠黏膜上皮结构及内毒素移位的实验研究

目的研究梗阻性黄疸对大鼠肠黏膜上皮结构及内毒素移位的影响。方法 30只健康雄性Wistar大鼠随机分为3组:正常对照组、假手术组、梗阻性黄疸组(OJ组)。OJ组制成梗阻性黄疸动物模型,7 d后各组同一时间点取材。观察肠黏膜上皮组织形态变化,检测门静脉血内毒素、D-乳酸含量。结果 OJ组大鼠肠黏膜上皮结构受损,门静脉血内毒素、D-乳酸水平显著高于正常对照组和假手术组(P<0.05)。结论梗阻性黄疸可导致肠黏膜上皮结构完整性受损,是发生细菌及内毒素移位的形态学基础。     

严重腹腔感染早期肠黏膜病理损害的实验观察

目的 观察严重腹腔感染时肠黏膜的形态学变化,探讨严重腹腔感染早期肠黏膜病理损害与细菌易位的关系。方法 SD大鼠60只．随机分成实验组和对照组,每组30只。实验组采用盲肠结扎加穿孔手术制作严重腹腔感染模型,对照组仅行单纯剖腹手术。于术后1、2、4d每组取空肠、回肠组织,行常规病理检查和电镜下观察：心脏穿刺取血1ml行血浆内毒素水平测定;取血2ml作细菌培养。结果 对照组空、回肠黏膜光镜、电镜下观察均未见异常。实验组光镜下可见空、回肠黏膜和黏膜下层间质水肿、血管充血,黏膜层有中性粒细胞浸润,肠绒毛毛细血管充血,部分区域有黏膜上皮脱落,浆膜层明显炎性渗出;电镜下可见肠上皮细胞微绒毛稀疏,排列不整齐,部分脱落,肠上皮细胞间紧密连接出现异常．结构松弛。实验组术后血浆内毒素水平较对照组升高5～12倍,术后1、2、4d血细菌培养阳性率分别为20％、30％和10％,对照组血细菌培养均为阴性。结论 严重腹腔感染早期出现肠黏膜病理损害,诱发肠道细菌和内毒素易位。     

鲜生地(冻干粉)对肝损伤模型大鼠肠生物屏障的影响

[目的] 探讨鲜生地（冻干粉）对肝损伤模型大鼠肠生物屏障的影响。[方法]采用Pringle’s maneuver法制作大鼠肝缺血再灌注损伤模型。将64只实验大鼠随机分为假手术组、模型组、鲜生地（冻干粉）组及乳果糖组。观察大鼠粪便球杆菌比例、菌落培养,测定血清内毒素水平。[结果] 鲜生地组、乳果糖组粪便中益生菌增加,大肠杆菌减少,血清内毒素水平降低。[结论] 鲜生地能够调节肠道菌群,降低血内毒素水平,可能通过改善肠生物屏障,使肝细胞得到恢复。     

腹部手术后肠粘膜屏障障碍及其临床意义

目的 探讨腹部外科术后患者血浆谷氨酰胺(Gln)水平、肠粘膜通透性与细菌移位及细菌移位与全身炎症反应综合征(SIRS)之间的关系.方法 腹部择期手术患者42例,于术前、术后2、7d采集外周血进行血浆Gin浓度和全血细菌DNA检测,同时进行尿中乳果糖/甘露醇(L/M)比值测定,分析肠粘膜屏障障碍与术后SIRS发生情况的关系.结果 血浆Gln浓度与术前比较,术后2、7 d血浆Gln浓度显著降低(P<0.01).与术前比较,术后尿中L/M比值显著增高(P<0.01).这42例手术病人术前PCR结果均为阴性,术后5例变为阳性,其中,术后2d的PCR阳性率为9.5%(4/42),术后7 d的PCR阳性率为2.4%(1/42).术后2 d的PCR阳性患者血浆Gin浓度较阴性患者显著降低(P<0.01).术后2d的PCR阳性患者的L/M比值较阴性患者显著增高(P<0.01).术后42例病人中,26例发生SIRS:SIRS组术后2 d Gln浓度较非SIRS组显著下降(P<0.01),而L/M比值显著增加(P<0.01).术后26例SIRS患者中5例PCR阳性,而16例非SIRS患者的PCR结果均为阴性,两组间PCR阳性率比较无显著性差异(P>0.05).结论 腹部手术后患者血浆Gln水平下降和肠粘膜通透性增高与细菌移位的发生密切相关,肠粘膜屏障障碍可能是术后感染的原因之一.     

胰十二指肠切除术后肠黏膜屏障损伤及SIRS与肠道细菌移位的关系

目的探讨胰十二指肠切除术后肠黏膜屏障损伤与肠道细菌移位的关系。方法将50例行胰十二指肠切除术患者术前及术后24、48、72 h检验全血细菌DNA、血浆D-乳酸和内毒素水平与空白对照组比较。结果术前所有患者细菌DNA PCR结果均为阴性,术后72 h内PCR检测阳性10例(20.00%),术后SIRS组与无SIRS组差异有统计学意义(P<0.01)。空白对照组与病例组术前血浆D-乳酸和内毒素水平差异无统计学意义(P>0.05),病例组术后各时段血浆D-乳酸和内毒素均显著高于术前(P<0.05),胰十二指肠切除术后患者血浆D-乳酸和内毒素呈正相关(P<0.05)。PCR阳性组血浆D-乳酸和内毒素显著高于PCR阴性组(P<0.01),SIRS组血浆D-乳酸和内毒素显著高于无SIRS组(P<0.01)。结论胰十二指肠切除术后肠黏膜屏障损伤、SIRS与肠道细菌移位密切相关,细菌DNA PCR有助于早期诊断肠道细菌移位。     

18例非失血性休克患者输血后临床分析

目的：研究休克患者输血后出现的病情变化与再灌注综合征的关系。方法：回顾性总结分析１９９３年１月～１９９７年１月我院收治的１８例非失血性休克患者输血前后临床表现比较。结果：１８例患者均发生病情突然恶化,其中６６７％（１２／１８）发生在输血４～２４ｈ内,１３例死亡,５例恢复正常。结论：休克患者输血后病情恶化可能与缺血 再灌注损伤有关。提出对非失血性休克患者输血应持慎重态度,若必须输血,则应在休克早期进行,同时注意预防再灌注损伤。     

雌激素对创伤失血性休克肠道细菌移位的影响

目的探讨雌激素对创伤失血性休克(Trauma/hemorrhageshock,T/HS)肠粘膜屏障损伤以及肠道细菌移位的影响。方法雌性青春期Wistar大鼠40只,随机分为卵巢切除组10只,对照组10只,雌二醇组10只,大剂量雌二醇组10只,观察T/HS60min,复苏4h后的肠粘膜损伤程度(Chiu氏评分),并取肠系膜淋巴结、肝组织及门静脉血进行细菌培养,改良鲎试剂法测定血浆内毒素含量。结果雌二醇组和大剂量雌二醇组与其他两组相比,肠粘膜Chiu氏评分显著降低,细菌培养计数及内毒素含量明显减少,P均<0.05。结论雌激素能改善创伤失血性休克大鼠的肠粘膜损伤程度,降低肠道细菌及内毒素移位的发生率。     

早期腹腔穿刺引流对重症急性胰腺炎大鼠肠道细菌移位的影响

目的 探讨早期腹腔穿刺引流(abdominal paracentesis drainage,APD)对重症急性胰腺炎(severe acute pancreatitis,SAP)大鼠肠道细菌移位的影响.方法 将质粒标记有绿色荧光蛋白的大肠杆菌(E.coli marked with green fluorescent protein,GFP-E.coli)灌饲给SD大鼠,使其成功定植于大鼠肠道.将定植了GFP-E.coli的大鼠分为假手术组(Sham组)、SAP组和APD组,每组12只.逆行胰胆管注射5％牛磺胆酸钠制作大鼠SAP模型.SAP造模后于右下腹留置腹腔引流管,为APD治疗组.造模后24 h无菌条件下取材并处死.对比各组大鼠胰腺组织病理学评分,血液、肠系膜淋巴结(mesentericlymph nodes,MLN)、胰腺组织细菌移位情况,以及血清炎性因子CRP、TNF-α及IL-1β水平.结果 与假手术组比较,SAP组及APD组胰腺组织病理学评分,血液、MLN及胰腺组织细菌移位程度,血清内毒素水平,以及血清炎性因子CRP、TNF-α及IL-1β水平均显著升高(P＜0.05);与SAP组比较,APD组上述各项指标均显著降低(P＜0.05).结论 早期APD能减少SAP大鼠肠道细菌移位及全身炎症水平,并可能因此改善SAP.     

胆色素结石与肠屏障关系的动物实验及临床观察

目的 探讨胆色素结石形成与肠屏障功能间的关系及作用机制.方法 豚鼠80只随机分为对照组(CON)20只、成石组(PS)30只、肠黏膜保护组(GLN)30只,分别给予正常饲料、胆色素结石致石饮食、添加肠黏膜保护剂谷氨酰胺的致石饮食,饲养8周建立胆囊胆色素结石模型.检测并比较各组胆结石成石率、血浆二胺氧化酶(DAO)、血浆内毒素、尿甘露醇/乳果糖排泄率、腹腔淋巴结细菌移位和胆汁β-葡萄糖醛酸酶(β-G酶)活性.临床病例59例,分为对照组、胆同醇结石组、胆色素结石组,检测并比较各组血浆DAO、血浆内毒素.另选临床病例130例,分为对照组、胆固醇结石组、胆色素结石组,检测并比较各组尿99mTc-DTPA排泄率.结果 豚鼠模型中,成石组成石率为73.9%,与正常组相比,成石组血浆DAO、血浆内毒素水平、尿甘露醇/乳果糖排泄率、腹腔淋巴结细菌阳性率和内、外源性胆汁β-葡萄糖醛酸酶活性增高.肠黏膜保护组成石率下降至44.4%,除胆汁β-葡萄糖醛酸酶活性外其余各指标均较成石组降低.临床实验中,结石组患者血浆DAO、血浆内毒素水平高于对照组,胆色素结石组患者尿99mTc-DTPA排泄率高于对照组.结论 动物模型中胆色素结石豚鼠和临床实验中胆结石患者均存在肠黏膜屏障功能异常,胆色素结石形成与肠屏障功能异常之间具有一定的相关性.肠屏障功能异常可能通过细菌移位机制在促进胆色素结石的形成中发挥一定的作用.     

Intestinal permeability and orocaecal transit time in elderly patients with Parkinson's disease.

The aetiology of weight loss in patients with Parkinson''s disease is likely to be multifactorial. We studied 15 patients with Parkinson''s disease and 15 age- and sex-matched controls and looked for evidence of malabsorption due to small bowel bacterial overgrowth or alteration of intestinal permeability. There was a marked increase in orocaecal transit time in the patients with Parkinson''s disease, although lactulose hydrogen breath testing did not show evidence of small bowel bacterial contamination. Intestinal permeability measured by the differential sugar absorption test was also deranged. There was reduced absorption of mannitol in patients with Parkinson''s disease while lactulose absorption was similar in both groups, suggesting decreased non-mediated uptake across the enterocyte brush border membrane in patients with Parkinson''s disease.     

一氧化氮对内毒素血症大鼠肠道损伤及细菌移位的影响

目的 一氧化氮（NO）参与休克的血管扩张,血压下降,但它对组织损伤,特别是肠道的损伤及细菌移位的作用仍不十分清楚。本实验以NO合酶（NOS）底物左旋精氨酸及其抑制剂硝基左旋精氨酸（LNNA）为工具,观察NO对内毒素血症时大鼠肠道损伤及细菌移位的影响。方法 用内毒素（LPS,10mg/kg,ip）复制内毒素血症模型,给予LNNA或L-arg抑制或促进NO合成,测定肠道质过氧化物丙二醛（MDA)的含量,二胺氧化酶（DAD）活性及肠系膜淋巴结细菌培养。结果 LPS可降低肠细胞DAO活性,增加MDA含量和肠系膜淋巴细菌移位的发生率和细菌数量;用LNNA抑制NO后可加重LPS的上述作用,而给予L－arg促进NO合成则可减轻LPS的作用。结论 本实验结果表明在内毒素血症时,抑制NO可加重肠道损伤和细菌移位的发生,提示NO对肠组织有一定的保护作用。     

急性胰腺炎肠黏膜损伤情况及通透性改变的实验研究

目的：观察实验性重症急性胰腺炎（ANP）鼠肠通透性的改变,并观察肠黏膜形态变化及细菌移位的关系。方法：实验性大鼠41只,随机分为胰腺炎组和对照组。利用电子显微镜以硝酸镧作为踪剂观察肠黏膜通透性和肠细胞的渗透性。结果：回肠黏膜出现明显病理改变,肠黏膜通透性和肠细胞渗透性明显增高。胰腺炎组肠系膜淋巴结和腹水标本培养出肠道菌属者,结论：ANP时存在着严重的肠道屏障功能损伤。发病时肠黏膜即遭到严重破坏,肠通透性增高,从而引起肠道细菌移位。     

Bacterial translocation and change in intestinal permeability in patients after abdominal surgery

The purpose of this study was to investigate bacterial translocation and change in intestinal permeability in patients after abdominal surgery. Sixty-three patients undergoing elective abdominal surgery were enrolled in the study. Blood samples were collected prior to operation and 2, 24, 48 h after surgery for bacterial culture, microbial DNA extraction, plasma D-lactate and endotoxin measurement. PCR analysis was performed after DNA extraction, with β-lactosidase gene of E. coli and 16S rRNA gene as target genes. All patients were observed for a period of 30 days for infectious complications. Our results showed that no bacterial DNA was detected before surgery, but after operation it was found in 12 patients （19.0%）. Bacterial DNA was detected in 41.7% （10/24） of SIRS patients and 5.1% （2/39） of non-SIRS patients （P〈0.01）. About 83.3% of PCR-positive patients developed systemic inflammatory response syndrome （SIRS）, but only 27.5% of PCR-negative patients did so （P〈0.01）. Two thirds of PCR-positive patients developed infectious complications, while none of PCR-negative patients did （P〈0.01）. The blood culture was positive only in 3 patients （4.8%）, who were all PCR-positive. E. coli DNA was found in 66.7% of the PCR-positive patients. The plasma levels of D-lactate and endotoxin were elevated significantly 2, 24 and 48 h after operation in PCR-positive patients, with a significant positive correlation found between them （r=0.91, P〈0.01）. It is concluded that increased intestinal permeability was closely related with bacterial translocation. Intestinal bacterial translocation （most commonly E. coli） might occur at early stage （2 h） after abdominal surgery. Postoperative SIRS and infection might bear a close relationship with bacterial translocation.