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.     

肝炎肝硬化患者肠壁通透性变化与细菌移位的临床研究

目的探讨肝炎肝硬化患者肠壁通透性与细菌及其毒素移位的关系。方法选择乙型肝炎肝硬化患者57例和16例健康志愿者,其中肝硬化患者按Child-Pugh分级分成A级14例,B级15例,C级28例。用高效液相色谱法（HPLC）测定各组尿中乳果糖和甘露醇（L/M）比值,同时采用鲎试验检测血浆内毒素,比较各组以及合并自发性细菌性腹膜炎（SBP）患者两指标改变情况。结果肝硬化各组内毒素水平均较正常对照组显著升高（P〈0.05）,而L/M值仅在肝硬化C级组显著升高（P〈0.01）,合并SBP肝硬化患者较未合并SBP肝硬化患者L/M值显著升高（P〈0.01）。结论严重肝硬化和合并腹腔感染的肝硬化患者肠壁通透性升高,是产生肠源性感染的重要机制。     

Prophylactic treatment with growth hormone improves intestinal barrier function and alleviates bacterial translocation in stressed rats

Background Damage to the gut barrier often occurs during critical illnesses. In such cases, it is very important to alleviate impairment of the intestinal barrier and protect intestinal barrier function. This study investigated the protective effect of growth hormone on intestinal barrier function in rats under stress.Methods This study consisted of prospective, randomized, and controlled animal experiments. Twenty-five Sprague-Dawley rats served as total parenteral nutrition (TPN) models and were divided into three groups: TPN group, sepsis (Sep) group, and growth hormone (GH) group. Another 8 rats served as normal controls. Each group received different stress stimuli. Rats were fed for 7 days, and samples were taken for examination 24 hours after gavaging with dual saccharides.Results The architecture of the small intestinal mucosa in the Sep group showed the most severe damage among all groups. Nitric oxide levels in blood plasma and immunoglobulin A levels in the intestinal mucosa of the GH group w     

肠道菌群移位对MODS发生发展的影响及其防治

人体肠道中储存的种类繁多的微生物共同构成了人体肠道的微生态环境,在正常情况下,肠道微生态处于平衡状态,肠道微生物与人体保持互利共生关系,但是当机体遭受强烈损害而处于应激状态时,肠道内蓄积的微生物失衡、细菌或其释放产物内毒素移位均可对炎症介质持续起着激惹作用,导致大量炎症介质的释放,造成内源性的感染,参与SIRS(systemic inflammatory response syndrome,SIRS)/MODS(multiple organ dysfunction syndrome,MODS)的发生发展,因此,肠道是炎症细胞激活、炎症介质释放的重要场地之一,也是MODS的源地之一,积极预防纠正肠道微生态失衡于MODS治疗及预后有着重要意义。     

急性坏死性胰腺炎后肠道微生态失调与细菌移位关系的研究

15只杂种犬,分为实验组（n＝8）和对照组（n＝7）。七天后活杀。结果发现,实验组犬肠粘膜及内容物中大肠杆菌计数高出对照组10－300倍,而双歧杆菌及乳杆菌则明显减少（P＜0.01）;肠粘膜双歧杆菌／大肠杆菌比值严重倒置（P＜0．05）;肝、胰、脾、肺、肾及肠系膜淋巴结出现了肠道细菌移位;第1、2天血培养结果分别为6／8和5／8。本研究证实,急性坏死性胰腺炎后肠道出现明显的微生态失调,肠道细菌移位到胰腺及其它脏器,成为胰腺及胰周感染的根源。     

正常国人乳果糖和甘露醇排出率比值

目的测定正常国人口服乳果糖、甘露醇测试液后尿中乳果糖／甘露醇排出率比值（Ｌ／Ｍ）。方法用带脉冲电化学检测器的高压液相仪（ＨＰＬＣ－ＰＥＤ）分别测定６０例健康志愿者口服以往剂量（乳果糖１０ｇ、甘露醇５ｇ）和小剂量（乳果糖２ｇ、甘露醇１ｇ）测试液后,尿中乳果糖和甘露醇浓度,并计算乳果糖和甘露醇尿中排出率及其比值。结果口服以往剂量和小剂量测试液６ｈ后,正常国人尿中Ｌ／Ｍ比值分别为０．０２６±０．００６和０．０３６±０．００８。结论ＨＰＬＣ－ＰＥＤ方法检测灵敏度高,可减少乳果糖和甘露醇的测试量,测定乳果糖与甘露醇排出率比值反映肠粘膜通透性是一种实用的临床方法。     

益生菌对炎症性肠病小鼠肠道菌群紊乱及细菌移位的影响

目的探讨植物乳杆菌（LP）对炎症性肠病（IBD）小鼠肠道菌群及细菌移位的影响。方法采用白介素10基因敲除（IL-10^-/-）小鼠作为IBD动物模型,将8周龄雌性小鼠随机分成空白对照组、IL-10^-/-组和IL—10^-/- ＋LP组三组。IL-10^-/- ＋LP组每日灌胃0．5mLLP菌液（1．0×10^9 CFU／mL）,其余两组灌胃Ringer缓冲液0．5mL,持续4周。以小鼠粪便中的双歧杆菌、乳酸杆菌、肠杆菌和产气荚膜梭菌数量及肠系膜淋巴结、脾脏细菌移位为检测指标。结果IL-10^-/-小鼠肠内双歧杆菌、乳酸杆菌含量明显下降,肠球菌、产气荚膜梭菌含量升高,且肠道细菌移位明显增加;而连续灌胃LP菌液4周后,益生菌发挥了对肠道的调节作用,纠正了肠道菌群失衡,并降低了肠道细菌移位。结论LP能纠正炎症性肠病小鼠肠道菌群紊乱,减少细菌移位,从而增强了肠道屏障功能。     

益生菌对炎症性肠病小鼠肠道菌群紊乱及细菌移位的影响

目的 探讨植物乳杆菌(LP)对炎症性肠病(IBD)小鼠肠道菌群及细菌移位的影响.方法 采用白介素10基因敲除(IL-10~(-/-))小鼠作为IBD动物模型,将8周龄雌性小鼠随机分成空白对照组、IL-10~(-/-)组和IL-10~(-/-)+LP组三组.IL-10~(-/-)+LP组每日灌胃0.5 mL LP菌液(1.0×10~9CFU/mL),其余两组灌胃Ringer缓冲液0.5 mL,持续4周.以小鼠粪便中的双歧杆菌、乳酸杆菌、肠杆菌和产气荚膜梭菌数量及肠系膜淋巴结、脾脏细菌移位为检测指标.结果 IL-10~(-/-)小鼠肠内双歧杆菌、乳酸杆菌含量明显下降,肠球菌、产气荚膜梭菌含量升高,且肠道细菌移位明显增加;而连续灌胃LP菌液4周后,益生菌发挥了对肠道的调节作用,纠正了肠道菌群失衡,并降低了肠道细菌移位.结论 LP能纠正炎症性肠病小鼠肠道菌群紊乱,减少细菌移位,从而增强了肠道屏障功能.     

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。     

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.     

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。     

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     

Effects of severe acute pancreatitis on gut bacteria/endotoxin translocation in pigs

Objective： To set up a swine model of severe acute pancreatitis（SAP） and to observe its relationship with the gut-originated bacteria/endotoxin translocation. Methods： Forty pigs weighing 17-22 kg were randomly diyided into SAP group （n=34） and sham-SAP group （n=6）. By injecting 1 ml/kg of combined solution of 5% sodium taurocholate and 8 000-10 000 benzoyl arginine ethyl ester（BAEE） units trypsin per milliliter into pancreas via pancreatic duct, SAP was induced under anesthesia. Endotoxin samples from vena cava were determined by chromogenic limulus amebocyte lysate （LAL） technique. Both portal and central vena blood samples were collected before and 72 h after the induction of SAP and cultured for both aerobic and anaerobic bacterial growth. Animals were sacrificed at the end of experiments by injecting 20 ml of 10% KCl intravenously and tissue specimens of mesenteriolum and mesocolon lymph nodes, lung, pulmonary portal lymph nods and pancreas were taken immediately after animal death, and homogenized for bacteriological studies. Results： Systemic plasma endotoxin levels increased rapidly 6 h post induction of SAP（PIS） with a peak at 48 h PIS （P〈0.01）. The magnitude of bacterial translocation in both portal and systemic blood and remote systemic organs as well were recovered PIS. Conclusion： （1） A swine model of SAP was established; （2）The early endotoxemia PIS seamed probable originated from gut endotoxin translocation; （3）The magnitude of bacterial translocation in both portal and systemic blood and the remote systemic organs as well were recovered at 72h PIS.     

基因重组碱性成纤维细胞生长因子对急性坏死性胰腺炎犬肠道细菌移位的影响

目的探讨基因重组碱性成纤维细胞生长因子（ｂＦＧＦ）对急性坏死性胰腺炎（ＡＮＰ）犬肠道细菌移位的影响。方法杂种犬２３只,分对照组（ｎ＝７）、ＡＮＰ组（ｎ＝８）和ｂＦＧＦ组（ｎ＝８）。ｂＦＧＦ组犬复制ＡＮＰ模型后,每日静脉注射ｂＦＧＦ（５μｇ／ｋｇ）。结果ｂＦＧＦ治疗后,ＡＮＰ犬肠粘膜损伤明显减轻,脏器细菌培养阳性率下降５０％,细菌移位数量减少９３．３％－９６．７％,肠粘膜蛋白质、ＤＮＡ含量显著增加（Ｐ＜０．０５）,丙二醛含量明显减少（Ｐ＜０．０５）。结论ｂＦＧＦ可显著减少ＡＮＰ时肠道细菌移位,其机制可能是通过增加肠粘膜蛋白质合成,促进肠粘膜损伤修复。     

微生态制剂对肝硬化患者肠道菌群及内毒素水平干预疗效观察

目的探讨微生态制剂对肝硬化患者肠道菌群、内毒素水平的干预作用及疗效。方法选择肝硬化患者57例,另选取24例健康体检者作为健康组,将57例肝硬化患者随机分为对照组25例,观察组32例,两组均采用常规护肝利尿治疗,观察组在此基础上,加用双歧杆菌三联活菌胶囊治疗8周,分别测定治疗前各组及治疗后两疾病组肠道10种细菌菌落数和内毒素水平。并对比两疾病组治疗前后并发症的变化情况。结果治疗前肝硬化患者的内毒素水平显著高于健康体检者(P<0.01),肠道菌群中的双歧杆菌、乳杆菌、肠杆菌显著低于健康体检者(P<0.05或0.01),葡萄球菌、梭菌显著高于健康体检者(P<0.01)。治疗前两疾病组内毒素水平及各肠道菌群菌落数比较差异无统计学意义(P均>0.05),治疗后对照组内毒素水平无显著变化(P>0.05),观察组内毒素水平显著低于治疗前(P<0.01);对照组中肠杆菌、真杆菌较治疗前显著下降(P<0.05或0.01),观察组中肠杆菌、双歧杆菌、乳杆菌、拟杆菌较治疗前显著升高,葡萄球菌、梭菌较治疗前显著降低(P<0.05或0.01),其中治疗后观察组的双歧杆菌、乳杆菌菌落数显著高于对照组(P<0.05或0.01)。治疗前后比较,观察组的并发症发生率显著降低(P<0.01),对照组无改变。结论微生态制剂能调节肠道菌群状态,提高肠道有益菌如双歧杆菌含量,降低内毒素水平,对降低肝硬化并发症发生率、改善预后具有重要的临床意义。     

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.     

大鼠门静脉高压对血清内毒素及肠黏膜的影响分析

目的研究大鼠单纯门脉高压对血清内毒素以及肠黏膜的影响。方法选取16只大鼠,分为空白对照组(4只)和模型组(3 d组、7 d组、10 d组,每组4只),模型组构建门脉部分结扎模型,分别在3 d、7 d、10 d采集血液及大鼠的空肠、回肠和结肠,采用ELISA法检测血清内毒素含量观察内毒素的变化情况,采集各组不同部位肠组织进行HE染色,进行病理组织学观察分析。结果模型组大鼠均成功构建了门静脉部分结扎模型。三个不同时间点血清内毒素的结果与正常对照组之间差异无显著性。成模3 d后各肠段还未发生很大的损伤;成模7 d后各肠段较3 d粘膜层的局部肠绒毛出现了部分破坏和肿胀,上皮细胞与固有层间连结出现了松散的状况;成模10 d较3 d和7 d的肠粘膜层、固有层均出现了明显的损伤。结论在肝功能正常的情况下,门脉高压短时间内可以造成肠黏膜的损伤,但肠道产生的内毒素不会超出肝脏的处理能力而出现血清内毒素的升高现象。     

细菌内毒素对钛板上人牙龈成纤维细胞生物学形态及OPG表达的影响

目的:通过研究不同浓度的细菌内毒素对钛板上人牙龈成纤维细胞及其产物骨保护蛋白(osteoprotegerin,OPG)的影响,了解内毒素对种植体软组织以及骨组织愈合的作用?方法: 人牙龈组织块培养并用免疫荧光染色方法进行组织来源鉴定,用0?10?100 μg/ml浓度的细菌内毒素分别刺激钛板上的牙龈成纤维细胞,扫描电镜观察牙龈成纤维细胞的形态,并用ELISA法检测OPG的含量并进行统计学分析?结果:10 μg/ml细菌内毒素刺激的牙龈成纤维细胞较正常组细胞伪足增多,细胞基质分泌增加,而100 μg/ml组的细胞数量及基质分泌明显减少?ELISA法表明低浓度条件下,OPG的含量随着细菌内毒素浓度增多而增加,但100 μg/ml 组OPG含量显著降低?结论:低浓度细菌内毒素可以促进牙龈成纤维细胞生长及分泌细胞基质OPG,而高浓度细菌内毒素则抑制牙龈成纤维细胞增殖且OPG表达降低?     

质子泵抑制剂与小肠细菌过生长关系的研究

目的：探讨质子泵抑制剂（PPIs）的使用与小肠细菌过生长（SIBO）发生之间的关系。方法：采用前瞻性对照性研究收集30例服用低剂量PPI的患者、28例服用高剂量PPI的患者,20例健康志愿者作为对照,通过乳果糖呼气H2试验连续观察SIBO的发生情况。结果：低剂量PPI组中SIBO阳性18例,阴性12例,高剂量PPI组阳性22例,阴性6例,对照组阳性1例,阴性19例,低剂量与高剂量PPI组分别与健康对照组比较差异有统计学意义（P〈0.01）,高剂量PPI组与低剂量组比较差异有统计学意义（P〈0.05）;两个服药组的SIBO阳性率随服药时间的增加而增加（P〉0.05）;同一时间段,高剂量PPI组的SIBO阳性率高于低剂量PPI组（P〉0.05）;两组PPI的使用时间与SIBO阳性率均存在正相关。结论：长期、大量使用PPI的患者可增加小肠细菌过生长的阳性率,可能进一步增加疾病发生的风险。     

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.