Small intestinal bacteria overgrowth decreases small intestinal motility in the NASH rats

AIM： To explore the relationship between small intestinal motility and small intestinal bacteria overgrowth （SIBO） in Nonalcoholic steatohepatitis （NASH）, and to investigate the effect of SIBO on the pathogenesis of NASH in rats. The effect of cidomycin in alleviating severity of NASH is also studied.
METHODS： Forty eight rats were randomly divided into NASH group （n = 16）, cidomycin group （n = 16） and control group （n = 16）. Then each group were subdivided into small intestinal motility group （n = 8）, bacteria group （n = 8） respectively. A semi-solid colored marker was used for monitoring small intestinal transit. The proximal small intestine was harvested under sterile condition and processed for quantitation for aerobes （E. coli and anaerobes （Lactobacilli）. Liver pathologic score was calculated to qualify the severity of hepatitis. Serum ALT, AST levels were detected to evaluate the severity of hepatitis.
RESULTS： Small intestinal transit was inhibited in NASH group （P 〈 0.01）. Rats treated with cidomycin had higher small intestine transit rate than rats in NASH group （P 〈 0.01）. High fat diet resulted in quantitative alterations in the aerobes （E. coli） but not in the anoerobics （Lactobacill）. There was an increase in the number of E. coli in the proximal small intestinal flora in NASH group than in control group （1.70 ± 0.12 log10 （CFU/g） vs 1.28 ± 0.07 log10 （CFU/g）, P 〈 0.01）. TNF-α concentration was significantly higher in NASH group than in control group （1.13 ± 0.15 mmol/L vs 0.57 ± 0.09 mmol/L, P 〈 0.01）. TNF-α concentration was lower in cidomycin group than in NASH group （0.63 ± 0.09 mmol/L vs 1.13 ± 0.15 mmol/L, P 〈 0.01）. Treatment with cidomycin showed its effect by significantly lowering serum ALT, AST and TNF-α levels of NASH rats.
CONCLUSION： SIBO may decrease small intestinal movement in NASH rats. SIBO may be an important pathogenesis of Nash. And treatment with cidomycin by mouth can allevi     

Effects of psychological stress on small intestinal motility and expression of cholecystokinin and vasoactive intestinal polypeptide in plasma and small intestine in mice

AIM: To investigate the effects of psychological stress on small intestinal motility and expression of cholecystokinin (CCK) and vasoactive intestinal polypeptide (VIP) in plasma and small intestine, and to explore the relationship between small intestinal motor disorders and gastrointestinal hormones under psychological stress. METHODS: Thirty-six mice were randomly divided into psychological stress group and control group. A mouse model with psychological stress was established by housing the mice with a hungry cat in separate layers of a two-layer cage. A semi-solid colored marker (carbon-ink) was used for monitoring small intestinal transit. CCK and VIP levels in plasma and small intestine in mice were measured by radioimmunoassay (RIA). RESULTS: Small intestinal transit was inhibited (52.18±19.15% vs70.19±17.79%, P<0.01) in mice after psychological stress, compared to the controls. Small intestinal CCK levels in psychological stress mice were significantly lower than those in the control group (0.75±0.53 μg/g vs1.98±1.17 μg/g, P<0.01), whereas plasma CCK concentrations were not different between the groups. VIP levels in small intestine were significantly higher in psychological stress mice than those in the control group (8.45±1.09 μg/g vs7.03±2.36 μg/g, P<0.01), while there was no significant difference in plasma VIP levels between the two groups. CONCLUSION: Psychological stress inhibits the small intestinal transit, probably by down-regulating CCK and up-regulating VIP expression in small intestine.     

Separation of growth-stimulating peptides for Bifidobacterium from soybean conglycinin

AIM: To isolate and identify the soybean conglycinin peptides that selectively stimulates the growth of bifidobacteria in vitro, and to investigate the effect of soybean conglycinin peptides on intestinal ecosystem in vivo. METHODS: Soybean conglycinin was purified from soybean seeds by gel filtration(Sepharose-CL-6B). These proteins were submitted to hydrolysis by pepsin. Several growth-stimulating peptides for bifidobacteria were isolated chromatographically from pepsin hydrolysis of soybean conglycinin and identified by means of matrixassisted laser desorption ionization time of flight mass spectrometry(MALDI-TOF-MS). Parallel to in vitro study, in vivo experiments with soybean conglycinin peptides were performed in mice. Ninety male KM mice were randomly assigned into five groups of 16 mice each, and each group was administered for 21d intragastrically with physiological saline(control), conglycinin, pepsin-treated conglycinin(PTC), the most active fraction which isolated from pepsin-treated conglycinin(P2-PTC) and HCl-full hydrolysis of conglycinin(HCl-FHC), respectively. Intestinal microflora were evaluated by standard microbiologic methods and biochemical assays of cecal content samples after treatment. RESULTS: The results showed that the peptides which were isolated from soybean conglycinin could stimulate the growth of bifidobacteria in vitro, and the molecular mass of purified peptides with MALDI-TOF-MS ranged from 693.32 to 1829.55. Compared with control group, in vivo experiments showed that P2-PTC group decreased cecal pH(7.08±0.08 vs 7.21±0.09, P<0.05) and enterococcicourts(5.38±0.26 log_(10)CFU/g vs 5.78±0.19 log_(10)CFU/g, P<0.05), significantly increased sIgA level(172.08±35.40 ng/g vs 118.27±33.93 ng/g, P<0.01) and(3-galactosidase activity (1.28±0.23 U/g vs 1.82±0.58 U/g, P<0.05). CONCLUSION: The results have shown that conglycinin is good source for enzyme-mediated production of peptides which stimulate the growth of bifidobacteria. These peptides are inactive within the sequence of the parent protein but can be released during enzymatic hydrolysis, and in vivo experiments demonstrate that conglycinin peptides may be beneficial for improving gastrointestinal health.     

TLR4和肠道菌群在原发性肝癌进展中动态变化及与预后的关系

目的探讨Toll-样受体4(TLR4)和肠道菌群在原发性肝癌进展中动态变化情况,并分析其与预后之间的关系。方法选取100例慢性乙肝患者、80例肝硬化合并乙型肝炎患者和60例肝癌合并乙型肝炎患者作为研究对象,并分别命名为乙型肝炎组、肝硬化组和肝癌组,另选取年龄及性别与其匹配的100名健康体检者作为对照组。采用流式细胞术检测各组外周血单核细胞表面TLR4表达情况,收集各组新鲜粪便,并检测其肠道菌群的分布,并分析两者之间的关系。比较各组外周血单核细胞表面TLR4表达和肠道菌群分布差异,并分析其与肝癌患者预后之间的关系。结果对照组、乙型肝炎组、肝硬化组和肝癌组外周血CD14+TLR4+单核细胞阳性率分别为(34.92±4.79)%、(41.92±7.46)%、(49.21±8.83)%和(57.62±10.58)%,4组比较差异有统计学意义(F=78.624,P<0.01);双歧杆菌含量分别为(10.73±2.91)lg CFU/g、(8.15±2.04)lg CFU/g、(6.33±1.32)lg CFU/g和(5.21±0.87)lg CFU/g,4组比较差异有统计学意义(F=15.932,P<0.01);肠球菌含量分别为(4.91±0.78)log CFU/g、(6.44±1.29)log CFU/g、(8.11±2.08)log CFU/g和(10.21±2.77)log CFU/g,4组比较差异有统计学意义(F=12.372,P<0.01)。经Pearson相关分析得知,单核细胞表面TLR4表达与乳酸杆菌和双歧杆菌呈负相关(P<0.05),其相关系数分别为-0.643和-0.672;与肠球菌和大肠埃希菌呈正相关(P<0.05),其相关系数分别为0.771和0.734。随访1年,60例肝癌患者中,18例复发,15例死亡。复发者和未复发者外周血CD14+TLR4+单核细胞阳性率分别为(59.32±9.17)%和(55.21±5.23)%,两者比较差异有统计学意义(t=2.200,P=0.032);死亡者与生存者外周血CD14+TLR4+单核细胞阳性率分别为(61.04±10.23)%和(53.29±8.11)%,两者比较差异有统计学意义(t=2.998,P=0.004)。与未复发者和生存者比较,复发者和死亡者双歧杆菌和乳酸杆菌含量明显减少,但肠球菌和大肠埃希菌含量则明显升高,差异有统计学意义(P<0.05)。结论TLR4可促进HBV进展为肝癌,与肠道菌群变化明显相关,两者在肝癌预后监测中有一定价值。     

CpG寡脱氧核苷酸促进小鼠清除体内结核分枝杆菌的机制

目的 探讨CpG寡脱氧核苷酸(CpG-ODN)增强小鼠体内结核分枝杆菌清除能力的可能机制.方法 将雌性BALB/c小鼠随机分为免疫组36只和对照组24只,并分别腹腔注射CpG-ODN 30 μg(溶于200 μl生理盐水)和200 μl生理盐水.2周后每只小鼠经尾静脉注射结核分枝杆菌H37Rv 1×106 CFU.感染后3周和4周每组分别处死12只小鼠,免疫组小鼠饲养至感染后6周处死.肺和脾组织进行菌落计数,观察肺和脾组织的病理学变化.用实时定量聚合酶链反应方法检测肺和脾组织γ-干扰素、白细胞介素(IL)-4、IL-10、IL-12、IL-18和诱导型一氧化氮合酶(iNOS)mRNA表达的相对含量.组间比较采用t检验.结果 感染后3周,免疫组小鼠的肺和脾组织经培养后无结核分枝杆菌生长.感染后4周,免疫组小鼠的肺和脾组织培养后有结核分枝杆菌生长,但明显少于对照组;肺组织中IL-18、γ-干扰素和iNOS的mRNA表达的相对含量分别为(3.6±0.5、0.32±0.14和23.2±4.7),均明显高于对照组的(1.6±1.1、0.20±0.10和16.2±5.1),IL-12p40 mRNA表达的相对含量(5.7±0.6)明显低于对照组(14.5±1.9),IL-4和IL-10 mRNA表达的相对含量(0.30±0.09和0.28±0.05)与对照组(0.26±0.05和0.29±0.08)无明显差别;脾组织中IL-18、γ-干扰素和iNOS mRNA表达的相对含量(5.5±1.3、0.52±0.07和9.1±1.8)明显高于对照组(0.8±0.4、0.21±0.06和6.0±1.4),IL-12p40、IL-4和IL-10 mRNA表达的相对含量(2.1±0.3、0.23 ±0.10和0.10±0.04)明显低于对照组(5.1±0.4、1.21±0.26和0.57±0.13).与感染后4周比较,免疫组小鼠感染后6周,肺组织γ-干扰素mRNA表达的相对含量(0.95±0.27)明显增高,IL-18、IL-4和IL-10 mRNA表达的相对含量(3.51±0.86、0.45±0.35和0.24±0.21)无明显变化,IL-12p40和iNOS mRNA表达的相对含量(1.72±1.41和1.1±0.5)明显降低;脾组织IL-12p40和IL-18 mRNA表达的相对含量(0.08±0.02)和(0.11±0.03)明显降低,IL-10 mRNA表达的相对含量(0.39±0.11)明显增高,γ-干扰素、IL-4和iNOS mRNA表达的相对含量(0.63±0.32、0.30±0.16和8.4±2.7)无明显变化.结论 CpG-ODN增强小鼠清除体内结核分枝杆菌的能力与IL-18、γ-干扰素和iNOS的表达增强及IL-4和IL-10的表达抑制密切相关.     

Effect of emodin on small intestinal peristalsis of mice and relevant mechanism

AIM: To investigate the effect of emodin on small intestinal peristalsis of mice and to explore its relevant mechanisms. METHODS: The effect of emodin on small intestinal peristalsis of mice was observed by charcoal powder propelling test of small intestine. The contents of motilin and somatostatin in small intestine of mice were determinated by radioimmunoassay. The electrical potential difference (PD) related to Na+ and glucose transport was measured across the wall of reverted intestinal sacs. Na+-K+-ATPase activity of small intestinal mucosa was measured by spectroscopic analysis. RESULTS: Different dosages of emodin can improve small intestinal peristalsis of mice. Emodin increased the content of motilin, while reduced the content of somatostatin in small intestine of mice significantly. Emodin 0.2, 0.4, 0.8, and 1.6 g/L decreased PD when there was glucose. However, emodin had little effect when glucose was free. The Na+-K+-ATPase activity of small intestinal mucosa of mice in emodin groups was inhibited obviously. CONCLUSION: Emodin can enhance the function of small intestinal peristalsis of mice by mechanisms of promoting secretion of motilin, lowering the content of somatostatin and inhibiting Na+-K+-ATPase activity of small intestinal mucosa.     

Helicobacter pylori infection: mechanism of colonization and functional dyspepsia Reduced colonization of gastric mucosa by Helicobacter pylori in mice deficient in interleukin-10

BACKGROUND AND AIMS: Interleukin-10 (IL-10) is a potent anti-inflammatory and immunoregulatory cytokine. Mice deficient in IL-10 production (IL-10-/-mice) develop a spontaneous chronic enterocolitis, suggesting that IL-10 is an important regulator of the mucosal immune response in vivo. The objective of this study was to determine the role of endogenous IL-10 in the host defense against gastric colonization by Helicobacter pylori by using IL-10-deficient mice. METHODS: The IL-10-/-mice were inoculated intragastrically with a mouse-adapted H. pylori isolate (Sydney Strain 1). Gastric colonization by H. pylori (biopsy urease test and bacterial colony counts), serum levels of H. pylori-specific immunoglobulin (Ig) M, A, G, isotypes of IgG, and the gastric mucosal inflammatory scores were determined 6 weeks after inoculation. Results were compared with those obtained from H. pylori-infected control mice (IL-10+/-mice). RESULTS: The colonization of gastric mucosa by H. pylori was reduced approximately 100-fold (P < 0.0001) in IL-10-/-mice (log10 4.87 +/- 0.26CFU/g tissue) as compared to IL-10+/-mice (log10 6.64 +/- 0.22 CFU/g tissue). Furthermore, IL-10-/-mice infected with H. pylori had significantly higher H. pylori-specific IgA and IgG antibodies in serum (P < or = 0.01), and developed much more severe chronic active gastritis than infected IL-10+/-mice. The median scores of the infiltration of gastric mucosa by mononuclear cells and neutrophils were up to threefold higher in IL-10-/-mice than they were in IL-10+/-mice. CONCLUSION: Our studies suggest that endogenous IL-10 is an inhibitor of the protective immune response to H. pylori infection. Interleukin-10 participates in the downregulation of H. pylori-induced gastric inflammatory responses, which apparently confers a survival advantage to the organism promoting more effective colonization of gastric mucosa.     

Bacterial populations contaminating the upper gut in patients with small intestinal bacterial overgrowth syndrome

OBJECTIVE: Small intestinal bacterial overgrowth syndrome (SIBOS) is characterized by an abnormally high bacterial population level in the upper gut, exceeding 10(5) organisms/ml (5 log colony-forming unit (CFU)/ml). To understand its origin and select an appropriate antibiotic treatment, we have analyzed the bacterial populations contaminating the upper gut in SIBOS patients. METHODS: Jejunal samples of 63 consecutive patients with diarrhea or malabsorption and conditions predisposing to SIBOS were cultured and antibiotic sensitivities determined. RESULTS: Concentrations of total, microaerophilic, and anaerobic bacteria were confirmed in 55 patients with SIBOS (mean +/- SE) 7.6 +/- 0.8, 7.4 +/- 0.9, and 6.1 +/- 0.7 log CFU/ml, respectively. Mean number of bacterial genera was 4.6 +/- 0.8. The main bacteria recovered were (mean +/- SE log CFU/ml) Streptococcus (71%; 6.4 +/- 0.8), Escherichia coli (69%; 7.2 +/- 0.9), Staphylococcus (25%; 6.2 +/- 0.6), Micrococcus (22%; 6.0 +/- 0.7), Klebsiella (20%; 7.1 +/- 0.8), Proteus (11%; 6.1 +/- 0.8) for microaerophilic bacteria, and Lactobacillus (75%; 6.1 +/- 1.1), Bacteroides (29%; 6.9 +/- 1.3), Clostridium (25%; 5.5 +/- 1.0), Veillonella (25%; 5.3 +/- 0.7), Fusobacterium (13%; 4.8 +/- 0.5), and Peptostreptococcus (13%; 6.1 +/- 0.7) for anaerobic bacteria. Amoxicillin-clavulanic acid and cefoxitin were efficient on >90% of strains. CONCLUSIONS: Contaminating flora isolated in SIBOS include commonly identified oropharyngeal and colonic flora, but these occur in SIBOS at different levels from those usually found in their original location. These data may hopefully serve as a starting point to further therapeutic controlled studies.     

Quantitative and Qualitative Measurements of K Vitamins in Human Intestinal Contents

Little data are available with regard to the amount and types of bacterially synthesized menaquinones within the human intestinal tract. Quantitative reverse phase high performance liquid chromatographic (HPLC) analysis of the distal colonic contents of 10 male volunteers revealed the following: (mean +/- SEM) micrograms/g dry weight: MK-4 to MK-7 5.55 (+/- 0.27); MK-9,10 14.54 +/- 0.29; K1 1.31 (+/- 0.14). Similar analyses of the colostomy contents of subjects revealed a total menaquinone content of 8.85 micrograms/g dry weight. The total intestinal contents obtained from five subjects after isotonic saline purgation qualitatively revealed MK-4 to MK-11 with a mean (+/- SEM) content of MK-4 to MK-10 of 5.4 +/- 2.1 micrograms/g dry weight or a mean (+/- SEM) of 1.6 +/- 0.7 mg dry weight of the total contents (243 g). The quantitative mean growth for the major menaquinone producers Escherichia coli and Bacteroides species was 5.2 +/- 3.2 and 9.2 +/- 1.8 log10 CFU/g dry weight, respectively. These results indicate that menaquinones are present in significant concentration in the human intestinal tract, and a potentially large reservoir of vitamin K may be available to the host.     

Protective effect of L-arginine preconditioning on ischemia and reperfusion injury associated with rat small bowel transplantation

AIM: To investigate the protective effect and possible mechanism of L-arginine preconditioning on ischemia and reperfusion injury associated with small bowel transplantation (SBT). METHODS: Male inbred Wistar rats weighting between 180 and 250 g were used as donors and recipients in the study. Heterotopic rat SBT was performed according to the techniques of Li and Wu. During the experiment, intestinal grafts were preserved in 4℃ Ringer's solution for 8 h before being transplanted. Animals were divided into three groups. In group 1, donors received intravenous L-arginine (50 mg/kg, 1 mL) injection 90 min before graft harvesting. However, donors in control group were given normal saline (NS) instead. In group 3, six rats were used as sham-operated control. Specimens were taken from intestinal grafts 15 min after reperfusion. Histological grading, tissue malondialdehyde (MDA) and myeloperoxidase (MPO) levels were assessed. The graft survival of each group was monitored daily until 14 d after transplantation. RESULTS: Levels of MDA and MPO in intestine of sham-operated rats were 2.0±0.22 mmol/g and 0.66±0.105 U/g. Eight hours of cold preservation followed by 15 min of reperfusion resulted in significant increases in tissue MDA and MPO levels. Pretreatment with L-arginine before graft harvesting resulted in lower enhancement of tissue levels of MDA and MPO and the differences were significant (4.71±1.02 mmol/g vs 8.02±3.49 mmol/g, 1.03±0.095 U/g vs 1.53±0.068 U/g, P<0.05). Besides, animals in L-arginine pretreated group had better histological structures and higher 2-wk graft survival rates comparing with that in NS treated group (3.3±0.52 vs 6±0.1, 0/6 vs 6/6, P<0.05 or 0.01). CONCLUSION: L-arginine preconditioning attenuates ischemia and reperfusion injury in the rat SBT model, which was due to antioxidant activities partially.     

Effect of bowel rehabilitative therapy on structural adaptation of remnant small intestine: animal experiment

AIM To investigate the individual and thecombined effects of glutamine, dietary fiber,and growth hormone on the structural adaptationof the remnant small bowel.METHODS Forty-two adult male Sprague-Dawley rats underwent 85% mid-small bowelresection and received total parenteral nutrition(TPN) support during the first threepostoperational days. From the 4thpostoperational day, animals were randomlyassigned to receive 7 different treatments for 8days: TPNcon group, receiving TPN and enteral20g·L~1 glycine perfusion; TPN Gin group,receiving TPN and enteral 20 g·L~1 glutamineperfusion; ENcon group, receiving enteralnutrition (EN) fortified with 20 g·L~1 glycine; EN Gin group, enteral nutrition fortified with20g·L~1 glutamine; EN Fib group, enteralnutrition and 2 g·d~1 oral soybean fiber; EN GHgroup, enteral nutrition and subcutaneousgrowth hormone (GH) (0. 3IU) injection twicedaily; and ENint group, glutamine-enriched EN,oral soybean fiber, and subcutaneous GHinjection.RESULTS Enteral glutamine perfusion duringTPN increased the small intestinal villus height(jejunal villus height 250μm 29μm in TPNcon vs 330μm±54μm in TPN Gln, ileal villus height260μm±28μm in TPNcon vs 330μm±22μm inTPN Gln, P<0.05) and mucosa thickness(jejunal mucosa thickness 360μm ± 32μm inTPNcon vs 460μm±65μm in TPN Gln, ilealmucosa thickness 400μm ± 25μm in TPNcon vs490μm ± 11μm in TPN Gin, P<0.05) incomparison with the TPNcon group. Either fibersupplementation or GH administration improvedbody mass gain (end body weight 270 g ± 3.6 g inEN Fib, 265.7 g ± 3.3 g in EN GH, vs 257g±3.3g in ENcon, P<0.05), elevated plasmainsulin-like growth factor (IGF-I) level(880μg·L~1±52μg.L~(-1) in EN Fib, 1200μg·L(-1) 96μg·L~(-1) in EN GH, vs 620μg·L~(-1) ±43μg·L~1 in ENcon, P<0.05), and increased thevillus height (jejunum 560μm ± 44μm in EN ± Fib,530μm ± 30μm in EN±GH, vs 450μm±44μm inENcon, ileum 400μm ± 30μm in EN Fib, 380μm±49μm in EN ± GH, vs 320μm ± 16μm in ENcon,P<0.05) and the mucosa thickness (jejunum740μm ± 66μm in EN ± Fib, 705μm ± 27 μm in EN ±GH, vs 608μm ± 58μm in ENcon, ileum 570μm ±27μm in EN ± Fib, 560μm ± 56μm in EN ± GH, vs480μm ± 40μm in ENcon, P<0.05) in remnantjejunum and ileum. Glutamine-enriched ENproduced little effect in body mass, plasma IGF-I level, and remnant small bowel mucosalstructure. The ENint group had greater bodymass (280g ± 2.2 g), plasma IGF-1 level(1450μg.L~1 ± 137μg.L~1), and villus height(jejunum 620μm ± 56μm, ileum 450μm ± 31μm)and mucosal thickness (jejunum 800μm ± 52μm,ileum 633μm ± 33μm) than those in ENcon, EN Gln (jejunum villus height and mucosa thickness450μm ± 47μm and 610μm ± 63μm, ileum villusheight and mucosa thickness 330μm ± 39μm and500μm±52μm), EN GH groups (P<0.05), andthan those in EN Fib group although nostatistical significance was attained.CONCLUSION Both dietary fiber and GH whenused separately can enhance the postresectionalsmall bowel structural adaptation. Simultaneoususe of these two gut-trophic factors can producesynergistic effects on small bowel structuraladaptation. Enteral glutamine perfusion isbeneficial in preserving small bowel mucosalstructure during TPN, but has little beneficialeffect during EN.     

Effects of two methods of reconstruction of digestive tract after total gastrectomy on gastrointestinal motility in rats

AIM: To compare the effects of Roux-en-Y and jejunum interposition reconstruction procedures after total gastrectomy on intestinal motility.METHODS: Fifty male Sprague-Dawley rats were randomly divided into 5 groups: the control group (C), the laparotomy group (L), the jejunal transection group (JT) where the jejunum was transected 10 cm distal from the Treitz ligament and anastomosed, the Roux-en-Y group (RY) and the jejunal interposition group (JI) after total gastrectomy. To evaluate intestinal transit, the animals were given 0.1 ml Evans Blue solution through an orogastric tube. The rats were executed by CO2 inhalation 30 minutes later and the intestinal transmit was determined as the distance between the site of esophageojejunal anastomosis and the most distal site of small intestine colored with blue.RESULTS: One month after operation, the body weight of rats among JI and RY were almost identical (274.6±9.5 vs 270.4±10.6, P＞0.05), but were significantly lighter than those of JT and L group. Four months after the operation, the body weight in the JI group increased compared to the preoperative level (345.2±15.7 g vs 299.5±8.3 g, P＜0.01).However, the body weight of RY group decreased compared to preoperative (255.1±11.3 g vs 295.0±12.0 g, P＜0.01).The difference was more significant at six months postoperative. Small bowel transmit time in RY was slower than that in JI group and C group (P＜0.01).CONCLUSION: Changes of body weight and intestinal motility in JI group are less influenced than in RY group.     

Reduced interstitial cells of Cajal and increased intraepithelial lymphocytes are associated with development of small intestinal bacterial overgrowth in post-infectious IBS mouse model

Objective: Intestinal dysmotility and immune activation are likely involved in the pathogenesis of small intestinal bacteria overgrowth (SIBO) in irritable bowel syndrome (IBS). We aimed at investigating the role of interstitial cells of Cajal (ICC) and intestinal inflammation in the development of SIBO using a post-infectious IBS (PI-IBS) mouse model.

Materials and methods: NIH mice were randomly infected with Trichinella spiralis. Visceral sensitivity and stool pattern were assessed at 8-weeks post-infection (PI). Intestinal bacteria counts from jejunum and ileum were measured by quantitative real-time PCR to evaluate the presence of SIBO. ICC density, intraepithelial lymphocytes (IELs) counts, and intestinal cytokine levels (IL1-β, IL-6, toll-like receptor-4 (TLR-4), IL-10) in the ileum were examined.

Results: PI-IBS mice demonstrated increased visceral sensitivity compared with the control group. One-third of the PI-IBS mice developed SIBO (SIBO+/PI-IBS) and was more likely to have abnormal stool form compared with SIBO negative PI-IBS (SIBO?/PI-IBS) mice but without difference in visceral sensitivity. SIBO+/PI-IBS mice had decreased ICC density and increased IELs counts in the ileum compared with SIBO?/PI-IBS mice. No difference in inflammatory cytokine expression levels were detected among the groups except for increased TLR-4 in PI-IBS mice compared with the control group.

Conclusions: Development of SIBO in PI-IBS mice was associated with reduced ICC density and increased IELs counts in the ileum. Our findings support the role of intestinal dysmotility and inflammation in the pathogenesis of SIBO in IBS and may provide potential therapeutic targets.     

Helicobacter pylori infection in interleukin-4-deficient and transgenic mice

BACKGROUND: Interleukin (IL)-4 is a potent anti-inflammatory and Th2-type immunoregulatory cytokine. Helicobacter pylori infection in humans induces a polarized Th1 immune response characterized by increased production of interferon-gamma and absence of IL-4. This study was designed to determine the role of endogenous IL-4 in the host defence against gastric colonization by H. pylori using IL-4-deficient (IL-4-/-) and transgenic (IL-4 Tg) mice. METHODS: IL-4-/- mice and IL-4 Tg mice were inoculated intragastrically with H. pylori Sydney Strain 1. Gastric colonization by H. pylori (biopsy urease test and bacterial colony counts), serum levels of H. pylori-specific immunoglobulin M, A, G, isotypes of IgG, and the gastric mucosal inflammatory scores were determined 6 weeks after inoculation. Results were compared with those obtained from H. pylori-infected IL-4+/+ (controls for IL-4-/- mice) and IL-4 WT (controls for IL-4 Tg) mice. RESULTS: Colonization of the gastric mucosa by H. pylori in IL-4-/- mice was similar to that of control IL-4+/+ mice. There was no significant difference in titres of H. pylori-specific antibodies or gastric inflammatory scores between the two groups of mice. Colonization of gastric mucosa by H. pylori was consistently lower in IL-4 Tg mice (log10 6.40+/-1.09 CFU/g tissue) compared with IL-4WT mice (log10 7.20+/-0.34 CFU/g tissue), although the difference was not significant. Nevertheless, IL-4 Tg mice did have significantly higher titres of H. pylori-specific IgA and IgG (P< or =0.01). CONCLUSION: These results show that endogenous IL-4 is not a major contributor to host resistance to H. pylori, and enhanced IL-4 production has little if any effect on gastric colonization by this organism, despite increased specific antibody production.     

丁酸钠对DMH诱导大鼠肠道肿瘤的作用

目的:观察1,2-二甲基肼(1,2-dimethy lhydrazine,DMH)是否可以诱导出小肠肿瘤,并与大肠进行比较.并探讨丁酸钠(sodium butyrate,NaBt)对DMH诱导肠道肿瘤的作用.方法:实验动物用SPF级♂Wistar大鼠,大小为8-9周龄,共分4组:DMH组、DMH+NaBt组、NaBt组、对照组.实验30-32wk之后过量麻醉使大鼠安乐死,取出小肠和大肠,观察肿瘤部位、数量、大小等;然后用10%甲醛固定,制作病理切片,观察各部位组织学改变.结果:实验结束时DMH组大鼠死亡率60.00%(18/30),DMH+NaBt组死亡率48.00%(12/25).DMH组肠道肿瘤发生率66.67%(8/12),4只肿瘤单发,4只多发,荷瘤率1.33(16/12),小肠肿瘤4个,大肠肿瘤12个;DMH+NaBt组肠道肿瘤发生率84.62%(11/13),6只为单发肿瘤,5只多发,荷瘤率1.46(19/13),小肠肿瘤3个,大肠肿瘤16个.两组之间肿瘤发生率及荷瘤率均无统计学差异.无论是DMH组还是DMH+NaBt组,结肠肿瘤发生率都高于小肠肿瘤,统计学有显著性差异(75.00%vs25.00%,P<0.05;84.21%vs15.79%,P<0.01).DMH组中肿瘤平均体积>0.05cm3个数占37.5%;DMH+NaBt组中肿瘤平均体积>0.05cm3个数占73.68%,两组肿瘤大小有统计学差异(37.50%vs73.68%,P<0.05).与DMH+NaBt组相比,DMH组浸润深度多局限于黏膜层内,有统计学差异(43.75%vs10.53%,P<0.05).结论:DMH也可诱导大鼠小肠肿瘤的发生,但发生率明显低于大肠肿瘤;NaBt可能促进肿瘤生长,关于NaBt对DMH诱导的肠道肿瘤作用仍需做进一步的深入研究.     

Altered intestinal function in patients with chronic heart failure.

OBJECTIVES: We evaluated morphology and function of the gut in patients with chronic heart failure (CHF). BACKGROUND: Intestinal translocation of bacterial endotoxin may contribute to the inflammatory state observed in patients with CHF. The morphology and function of the gut may be abnormal. METHODS: We studied 22 patients with CHF (age 67 +/- 2 years, left ventricular ejection fraction [LVEF] 31 +/- 1%, New York Heart Association functional class 2.3 +/- 0.1, peak VO2 15.0 +/- 1.0 ml/kg/min) and 22 control subjects (62 +/- 1 years, LVEF 68 +/- 2%, peak VO2 24.7 +/- 1.3 ml/kg/min). Bowel wall thickness was assessed by transcutaneous sonography, small intestinal permeability by the lactulose-mannitol test, passive carrier-mediated transport by D-xylose test, large intestinal permeability by sucralose test (5- and 26-h urine collection, high-performance liquid chromatography), and mucosal bacterial biofilm by fluorescence in situ hybridization in biopsies taken during sigmoidoscopy. RESULTS: Chronic heart failure patients, compared with control patients, showed increased bowel wall thickness in the terminal ileum (1.48 +/- 0.16 mm vs. 1.04 +/- 0.08 mm), ascending colon (2.32 +/- 0.18 mm vs. 1.31 +/- 0.14 mm), transverse colon (2.19 +/- 0.20 vs. 1.27 +/- 0.08 mm), descending colon (2.59 +/- 0.18 mm vs. 1.43 +/- 0.13 mm), and sigmoid (2.97 +/- 0.27 mm vs. 1.64 +/- 0.14 mm) (all p < 0.01). Chronic heart failure patients had a 35% increase of small intestinal permeability (lactulose/mannitol ratio: 0.023 +/- 0.001 vs. 0.017 +/- 0.001, p = 0.006), a 210% increase of large intestinal permeability (sucralose excretion: 0.62 +/- 0.17% vs. 0.20 +/- 0.06%, p = 0.03), and a 29% decrease of D-xylose absorption, indicating bowel ischemia (26.7 +/- 3.0% vs. 37.4 +/- 1.4%, p = 0.003). Higher concentrations of adherent bacteria were found within mucus of CHF patients compared with control subjects (p = 0.007). CONCLUSIONS: Chronic heart failure is a multisystem disorder in which intestinal morphology, permeability, and absorption are modified. Increased intestinal permeability and an augmented bacterial biofilm may contribute to the origin of both chronic inflammation and malnutrition.     

Decreased expression of serotonin in the jejunum and increased numbers of mast cells in the terminal ileum in patients with irritable bowel syndrome

AIM： To investigate if there are changes in serotonin （5-HT） levels, enterochromaffin （EC） cells and mast cells in small intestinal mucosa of patients with irritable bowel syndrome （IBS）. METHODS： Diarrhea-predominant （IBS-D, n = 20）, or constipation-predominant （IBS-C, n = 18） IBS patients and healthy controls （n = 20） underwent colonoscopy and peroral small intestinal endoscopy, and mucosal samples were obtained at the descending part of the duodenum, proximal end of jejunum and terminal ileum. High-performance liquid chromatographyelectrochemistry and immunohistochemical methods were used to detect 5-HT content, EC cells and mast cells. RESULTS： （1） There were no differences in the number and distribution of EC cells between IBS patients and the normal group. （2） The mucosal 5-HT contents at the duodenum, jejunum and ileum in IBS-C patients were 182 ± 90, 122 ± 54, 61 ± 35 ng/mg protein, respectively, which were all lower than those in the normal group （256 ± 84, 188 ± 91, and 93 ± 45 ng/ mg protein, respectively）, with a significant difference at the jejunum （P 〈 0.05）. There were no differences in the small intestinal mucosal 5-HT contents between IBS-D patients and the normal group. The mucosal 5-HT contents at the duodenum were significantly higher than those at the ileum in the three groups （P 〈 0.001）. （3） The numbers of mast cells in patients with IBS-C and IBS-D at the ileum were 38.7 ± 9.4 and 35.8 ± 5.5/highpower field （hpf）, respectively, which were significantly more than that in the normal group （29.8 ± 4.4/hpf） （P 〈 0.001）. There was no significant difference in the numbers of mast cells at the other two parts between IBS patients and the normal group. The numbers of mast cells in IBS-C, IBS-D, and normal groups were all significantly higher at the ileum （38.7 ± 9.4, 35.8 ± 5.5, 29.8 ±4.4/hpf, respectively） than at the duodenum （19.6± 4.7, 18.5 ± 6.3, 19.2 ±3.3/hpf, respectively, P 〈 0.001）. CONCLUSIO     

Bioflora Probiotic in Immunomodulation and Prophylaxis of Intestinal Bacterial Translocation in Rats

The immunomodulator effect of Bioflora probiotic on T (CD4+) and B (CD20) lymphocytes in gastrointestinal mucosa and intestinal bacterial translocation was studied using Wistar rats (n = 10 per group). Two experiments were used: (I) stress with immobilization and water immersion at 22 degrees C for 7 h plus the application of indomethacin (Indo) 10 mg/kg SC every 24 h for 3 days (comparator group), and (II) stress experiment I with the addition of 1 mL of Bioflora applied through a orogastric tube every 12 h for 3 days. At the 4th day, in asepsis, a dissection laparotomy of liver, spleen, mesenteric lymphatic nodes, and cecum was performed for microbiological culture, and stomach, ileum, and colon were also dissected for immunohistochemical and quantification of CD4+ and CD20. Findings in experiment I revealed cecum bacterial overdevelopment of 6 x 10(10) +/- 2.3 x 10(9) colony-forming units (CFU) (P < 0.01) and positive cultures in liver, spleen, and all mesenteric lymphatic nodes. On the other hand, in the group treated with Probiotic Bioflora, cecum without overdevelopment (3 x 10(6) +/- 1.3 x 10(5) CFU), negative cultures in liver and spleen, and in lymphatic nodes two positive and eight negative cultures for E. coli and P. vulgaris (P < 0.01) were observed. Immunohistochemistry revealed a relevant increase of T lymphocytes (CD4+) in ileum and colon. Conclusions Bioflora probiotic was shown to be an intestinal immunomodulator that induced increased T (CD4+) lymphocytes that also offer prophylaxis of intestinal bacterial translocation in a stressed rat model.     

Proximal gastric response to small intestinal nutrients is abnormal in mechanically ventilated critically ill patients

AIM: To determine the response of the proximal stomach to small intestinal nutrients in critically ill patients. METHODS: Proximal gastric motility was measured in 13 critically ill patients (49.3±4.7 years) and 12 healthy volunteers (27.7±2.9 years) using a barostat technique. Recordings were performed at baseline, during a 60-min intra-duodenal infusion of Ensure (2 kcal/min), and for 2 h following the infusion. Minimum distending pressure (MDP), intra-bag volume and fundic wave activity were determined. RESULTS: The MDP was higher in patients (11.7±1.1 vs 7.8±0.7 mmHg; P < 0.01). Baseline intrabag volumes were similar in the 2 groups. In healthy subjects, a 'bimodal' proximal gastric volume response was observed. In patients, the initial increase in proximal gastric volume was small and delayed, but eventually reached a maximal volume similar to that of healthy subjects. In healthy subjects, the proximal gastric volume rapidly returned to baseline level after nutrient infusion (median 18 min). In contrast, the recovery of volume to baseline was delayed in critically ill patients (median 106 min). In 6 patients, the volume had not returned to baseline level 2 hours after nutrient infusion. In patients, fundic volume waves were less frequent (P < 0.05) and had lower amplitude (P < 0.001), compared to healthy subjects. CONCLUSION: In critical illness, proximal gastric motor responses to small intestinal nutrient stimulation are abnormal.     

暴发性肝衰竭小鼠细菌侵袭肠黏膜方式的研究

目的 通过研究细菌侵袭肠黏膜屏障的方式,探讨暴发性肝衰竭(FHF)并发自发性腹膜炎(SBP)的机制.方法 取240只雄性BALB/c小鼠,分为等渗盐水(NS)组(40只)、脂多糖(LPS)组(40只)、氨基半乳糖(GalN)组(40只).FHF模型组(120只).分别腹腔注射相同体积的NS、LPS(10μg/kg)、GalN(800 mg/kg)、LPS(10μg/kg)/GalN(800 mg/kg).注射处理后,分别于2、6、9、12 h和24 h处死小鼠(每个时间点处死8只小鼠).实验小鼠均在相应时间点摘取眼球,留取血清,并断头处死动物,留肝脏及大肠组织标本.用全自动生物化学分析仪检测ALT;对肝组织和大肠组织进行HE染色检测;透射电镜观察大肠黏膜超微结构及细菌侵袭肠黏膜的方式.用SPSS13.0统计软件进行数据分析,两组间ALT水平的分析采用Mann-Whitney U检验.结果 FHF模型组ALT水平、肝组织病理学检测结果及病死率和临床表现均符合FHF的诊断标准.4组小鼠注射处理后9 h,HE染色发现大肠组织仅有轻微水肿及少量炎性细胞浸润,此时,透射电镜下观察发现FHF模型组肠上皮细胞微绒毛断裂、脱落、变短,紧密连接(TJs)不完整,细胞器变化明显,HE染色发现FHF模型组肝脏呈成片的出血性坏死,残存的肝细胞肿胀,出血坏死区见较多炎性细胞浸润,但NS组、LPS组、GalN组肝脏组织病理形态及大肠黏膜超微结构变化不明显.FHF模型组注射处理后6～9 h,细菌以胞饮的形式穿入肠壁,细菌穿入肠壁区域的肠道黏膜绒毛脱落,TJs出现断裂,注射处理后12 h发现穿入的细菌以囊胞的形式存在.结论 LPS(10μg/kg)/GalN(800 mg/kg)联合注射建立的FHF小鼠模型是成功的.FHF时,肠黏膜TJs的断裂可能为肠道内细菌进入肠黏膜提供了条件,TJs的断裂可能是FHF并发SBP的原因之一.

Abstract：

Objective To explore the mechanism of fulminate hepatic failure (FHF) complicated with spontaneous peritonitis (SBP) through the research of bacteria invading the intestinal mucosa barrier.Methods 240 BalB/c male mice were divided into four groups as isotonic NS group (n = 40), lipopolysaccharide (LPS) group (n = 40), galactosamine (GalN) group (n = 40) and FHF model group (n = 120). Each mouse received same volume of NS, LPS (10 μ g/kg), GalN (800 mg/kg) or LPS (10 μ g/kg)/GalN (800 mg/kg)intraperitoneal injection according to its group. 8 mice were executed at 2, 6, 9, 12 and 24 hours after injection, respectively, and the liver and intestinal tissue samples were taken at the same time. ALT was measured by automatic biochemical analyzer and was compared between groups using Mann-Whitney U test.Liver and intestinal tissue received HE staining. The ultrastructure of intestinal mucosa and the method by which bacteria invaded the intestinal mucosa were observed by transmission electron microscopy. All data were analyzed by SPSS13.0 statistic software. Results ALT level, results of hepatic pathology, mortality and clinical manifestations of mice in the FHF model group met the diagnostic criteria of FHF. Intestinal tissue was found with slight edema and little inflammatory cells infiltration through HE staining in all the 4 groups of mice 9 hours after injection. Microvilli were found broken, shed and shorten in the intestinal epithelial cells with incomplete tight junction (TJs) and obviously changed organelles in the FHF model group of mice observed by transmission electron microscope. Mass hemorrhagic necrosis of liver cells with remnant liver cells swelling and many inflammatory cells infiltration by HE staining in the FHF model group. But the changes in hepatic pathology and intestinal mucosa ultrastructure were not so obvious in the mice of NS, LPS and GalN groups. Bacteria penetrated the intestinal wall by pinocytosis 6-9 hours after injection in the FHF model group, the microvilli were broken off and TJs turned rupture in the areas that the bacteria penetrated.The bacteria were found in the form of cyst 12 hours after injection. Conclusions LPS (10 mg/kg)/GalN (800 mg/kg) combined injection was successful in establishing the FHF mice model. The rupture of TJs may provide conditions for intestinal bacteria to penetrate the intestinal mucosa in FHF. Rupture of TJs may be one of the reasons why FHF was complicated with SBP.