Role of TFF in healing of stress-induced gastric lesions

AIM: To determine the changes of pS2 and ITF of TFF expression in gastric mucosa and the effect on ulcer healing of pS2, ITF to Water-immersion and restraint stress (WRS)in rats.METHODS: Wistar rats were exposed to single or repeated WRS for 4 h every other day for up to 6 days. Gastric mucosal blood flow (GMBF) was measured by LDF-3 flowmeter and the extent of gastric mucosal lesions were evaluated grossly and histologically. Expression of pS2 and ITF mRNA was determined by RT-PCR. Immunohistochemistry was used to further detect the expression of pS2 and ITF.RESULTS: WRS applied once produced numerous gastric mucosal erosions, but the number of these lesions gradually declined and GMBF restored at 2, 4, 8 h after stress. The area of gastric mucosal lesion was reduced by 64.9 % and GMBF was increased by 89.8 % at 8 h. The healing of stress-induced ulcerations was accompanied by increased expression of pS2 (0.51±0.14 vs0.77±0.11, P＜0.01) and ITF (0.022±0.001 vs 0.177±0.010, P＜0.01). The results were demonstrated further by immunohistochemistry of pS2(0.95±0.11 vs1.41±0.04, P＜0.01) and ITF (0.134±0.001 vs 0.253±0.01,P＜0.01). With repeated WRS, adaptation to this WRS developed, the area of gastric mucosal lesions was reduced by 22.0 % after four consecutive WRS. This adaptation to WRS was accompanied by increased GMBF (being increased by 94.2 %), active cell proliferation in the neck region of gastric glands, and increased expression of pS2 (0.37±0.02 vs 0.77±0.01, P＜0.01) and ITF (0.040±0.001 vs0.372±0.010, P＜0.01). The result was demonstrated further by immunohistochemistry of pS2 (0.55±0.04 vs 2.46±0.08, P＜0.01) and ITF (0.134±0.001 vs0.354±0.070,P＜0.01).CONCLUSION: TFF may not only participate in the early phase of epithelial repair known as restitution(maked by increased cell migration),but also play an important role in the subsequent, protracted phase of glandular renewal(made by cell proliferation).     

Influence of NG‐nitro‐L‐arginine methyl ester and L‐arginine on gastric mucosal tolerant cytoprotection under stress

OBJECTIVE : To determine the role of endogenous nitric oxide (NO) in gastric mucosal tolerant cytoprotection under stress and its possible mechanism. METHODS : Sprague–Dawley rats were exposed to repeated water immersion and restraint stress (WRS), during which N^G‐nitro‐L ‐arginine methyl ester (L ‐NAME), a non‐selective NO synthase inhibitor, and L ‐arginine (L ‐Arg), a substrate for NO synthesis, were administered to inhibit or promote the synthesis of endogenous NO, respectively. Gastric mucosal blood flow (GMBF) was measured with an LDF‐3 Flowmeter (Electronic Instrument Factory of Nankai University, Tianjin, China), the NO level in the gastric mucosa was monitored by the Griess reaction and gastric mucosal lesions were evaluated using the ulcer index (UI). The relationships between changes in GMBF, UI and NO content in the gastric mucosa were analyzed by linear correlation analysis. RESULTS : Repeated WRS induced gastric mucosal tolerant cytoprotection and this was accompanied by increased GMBF and NO levels in the gastric mucosa. Inhibition of endogenous NO synthesis by L ‐NAME worsened mucosal lesions induced by single WRS and, after repeated WRS, the adaptive incremence in GMBF was abolished and the NO content in the gastric mucosa was significantly reduced. In contrast, enhancement of endogenous NO synthesis by L ‐Arg attenuated mucosal erosions caused by single WRS. After repeated WRS, GMBF and the NO content in the mucosa increased gradually. Mucosal lesions were negligible after rats were exposed to the fourth WRS. CONCLUSIONS : During the tolerant cytoprotection, GMBF, UI and the NO content showed regular changes and there were good relationships between them. L ‐NAME and L ‐Arg changed the levels of endogenous NO, which, accordingly, affected GMBF and the gastric tolerance. By regulating GMBF, endogenous NO may play an important role in the gastric mucosal tolerant cytoprotection under stress. Inhibition of the synthesis of NO delayed the induction of tolerant cytoprotection, whereas increased NO synthesis promoted cytoprotection.     

Enhanced resistance of gastric mucosa to damaging agents in the rat stomach adapted to Helicobacter pylori lipopolysaccharide

BACKGROUND AND AIM: Lipopolysaccharide (LPS) has been proposed to act as one of numerous virulence factors in the Helicobacter pylori (HP)-infected stomach. However, little is known as to whether the gastric mucosa can withstand the repeated LPS insult, and how the possible adaptation to this endotoxin influences the damage induced by strong irritants. We determined the effect of a single or repeated parenteral administration of LPS obtained from HP on acute gastric lesions induced by intragastric application of 100% ethanol (1.5 ml) and by water immersion and restraint stress (WRS). METHODS: The area of the gastric lesions was measured by planimetry, mucosal gastric blood flow (GBF) was determined by H(2) gas clearance, and gastric luminal content was collected for the determination of luminal NO(2)(-)/NO(3)(-) levels by the Griess reaction. Biopsy samples were taken for the measurement of prostaglandin (PG) E(2) by radioimmunoassay and mucosal expression of constitutive and inducible nitric oxide synthase (cNOS and iNOS), constitutive (COX-1) and inducible cyclooxygenase (COX-2), heat shock protein 70 (HSP 70) mRNA and protein were analyzed by RT-PCR and Western blot. RESULTS: HP LPS (1 mg/kg i.p.) injected once or 5 times produced negligible macroscopic injury and failed to influence GBF significantly compared to the injuries recorded in vehicle-controlled rats. Single and repeated (5 times) administration of HP LPS significantly reduced ethanol- and WRS-induced lesions, these protective effects were accompanied by a rise in GBF and excessive luminal release of NO. The suppression of NOS activity by L-NAME (20 mg/kg i.p.), a nonspecific NOS inhibitor, or L-NIL (30 mg/kg i.g.), a specific iNOS inhibitor, and of COX-2 activity by NS-398 reversed the protective and hyperemic effects of single or repeated LPS administrations against ethanol and WRS damage and the accompanying rise in NO and PGE(2) production. These effects of L-NAME were significantly antagonized by the addition of L-arginine, a substrate for NO synthesis. The signals for cNOS, COX-1 and HSP 70 mRNA were detected by RT-PCR in the vehicle-treated gastric mucosa, whereas gene and protein expression of iNOS, COX-2 and HSP 70 mRNA were significantly increased only in rats treated with 1 or 5 applications of HP LPS. CONCLUSIONS: Repeated injections of HP LPS enhance gastric mucosal resistance to the mucosal damage induced by ethanol and WRS via a mechanism involving mucosal overexpression of iNOS, COX-2 and HSP 70 with subsequent excessive production of NO and PGE(2).     

Expression of COX-2, iNOS, p53 and Ki-67 in gastric mucosa-associated lymphoid tissue lymphoma

AIM: To assess the expression of cyclooxygenase-2 (COX-2),nitric oxide synthase (iNOS), p53 and Ki-67 in gastric mucosaassociated lymphoid tissue (MALT) lymphoma and clarify the relationship between COX-2 expression and iNOS or p53 expression in these patients.METHODS: The expressions of COX-2, iNOS, p53 and Ki-67 were detected in 32 gastric MALT lymphoma specimens and 10 adjacent mucosal specimens by immunohistochemical Envision method.RESULTS: COX-2 and iNOS expressions were significantly higher in gastric MALT lymphoma tissues than those in adjacent normal tissues. The expression of COX-2 was observed in 22 of 32 cases of MALT lymphoma tissues (68.8%). A positive cytoplasmic immunoreactivity for iNOS was detected in 17 of 31 cases (53.1%). COX-2 expression in gastric MALT lymphoma tissues was positively correlated with iNOS expression (r=-0.448, P=0.010) and cell proliferative activity analyzed by Ki-67 labeling index (r=0.410, P=0.020).The expression of COX-2 protein did not correlate with age,sex, stage of disease, lymph node metastasis or differentiation.The accumulation of p53 nuclear phosphoprotein was detected in 19(59.4%) of tumors, p53 protein was expressed in 11 of 23 assessed LG tumors and in 8 of 9 assessed HG tumors.The difference of p53 positivity was found statistically significant between LG and HG cases (P=0.0302). The p53 accumulation correlated with advanced clinical stage (stage Ⅲ+Ⅳ vs stage Ⅰ+Ⅱ, P=0.017). There was a significant positive correlation between COX-2 expression and p53 accumulation status (r=0.403,/=0.022). The mean PI of Ki-67 in each grade group were 36.0±7.73% in HG and 27.4±9.21% in LG. High-proliferation rate correlated with HG tumors (r=0.419, P=0.017). The correlation coefficient showed a significant positive correlation between PI and COX-2 expression in MALT lymphoma patients (r=-0.410,P=0.020).CONCLUSION: COX-2 expresses in the majority of gastric MALT lymphoma tissues and correlates with cellular proliferation and iNOS expression. COX-2 overexpression is closely associated with p53 accumulation status, iNOS and COX-2 may play a synergistic role in the pathogenesis of gastric MALT lymphoma.     

Relationship between the expression of iNOS,VEGF,tumor angiogenesis and gastric cancer

AIM：To in vestigate the relationship between the expression of inducible nitric oxide synthase(iNOS),vascular endothelial growth factor(VEGF),the microvascular density(MVD)and the pathological features and clinical staging of gastric cancer.METHODS:Immunohistochemical staining was used for detecting the expression of iNOS and VEGFin46resected specimens of gastric carcinoma;the monoclonal antibody against CD34 was used for displaying vascular endothelial cells,and MVD was detected by counting of CD34-positive vascular endothelial cells.RESULTS:Of 46resected specimens of gastric carcinoma,the rates of expressions of iNOS and VEGF were 58.70%and76.09%,respectively,and MVDaveraged55.59±19.39,Judged by the standard TNM criteria,the rate of expression of iNOS in stageⅣ（84.46%)was higher than those in stageⅠ,Ⅱ,Ⅲ（Fish exact probabilities test,P=0.019,0.023and 0.033,respectively);the rates of expression of VEGFin stage Ⅲ,Ⅳ（76.0%,92.31%,respectively)were higher than those in stageⅠ,Ⅱ（Fis exact probabilities test,P=0.031,0.017,0.022and0.019).MVDs in stageⅢ,Ⅳ（64.72±14.96,67.09±18.29,respectively)were higher than those in stageⅠ,Ⅱ(t\2.378,4.015,2.503and2.450,P<0.05,P<0.001,P<0.001,P<0.05,respectively),In37gastric carcinoma specimens with lymph node metastasis,MVD(68.69±18.07)and the rates of expression of iNOS and VEGF(70.27%,83.78%,respectively)were higher than those in the specimens with absence of metastasis(t=2.205,X^2=6.3587,X^2=6.2584,P<0.01,P<0.05,P<0.05,respectively),MVD and the expressions of iNOS and EGF were not correlated to the location,size or grade of tumor,nor with the depth of invasion of tumor;MVDs in the positive iNOS and VEGF specimens(59.88±18.02,58.39±17.73,repectively)were higher than those in the negative iNOS and VEGF specimens(X^2=6.3587and 6.1574,P<0.05,P<0.05,respectively);thus the expressions of iNOS and VEGF was correlated to MVD,but the expression of iNOS was not correlated to that of VEGF,In addition.of the 46 surviving patients,the 5-year survival rate of patients with positive iNOS or VEGF tumors was significantly less than that of patients with negative iNOS-or VEGF tumors(X^2=4.3842and 5.4073,P<0.05,P<0.05.respectively).CONCLUSION:The expressions of iNOS and VEGF are colosely related to tumor angiogenesis,and are involved in the advancement and the lymph node metastasis;thusMVD and the expressions of iNOS and EGF may serve indexes for evaluating staging of gastric carcinoma and forecasting its risk of metastasis,which will help establish a comprehensive therapeutical measure of post-operative patients and provide a new approach to tumor therapy.     

左旋精氨酸甲酯及左旋精氨酸对应激状态下胃黏膜耐受性细胞保护作用的影响

目的：探讨内源性一氧化氮（NO）在应激状态下胃黏膜耐受性细胞保护中的作用及其可能的机制。方法：以重复浸水束缚应激（WRS）制作动物模型,以左旋精氨酸甲酯（L－NAME）或左旋精氨酸（L－Arg）抑制或促进内源性NO的合成,动态检测胃黏膜血流量（GMBF）、溃疡指数（UI）、黏膜一化氮含量的变化。结果：重复应激后,实验对照组大鼠UI明显下降,同时GMBF上升,黏膜内NO含量增高;L－NAME使WWRS引起的胃黏膜损伤加重,消除了GMBF的递增趋势,黏膜NO含量下降;而L－Arg可减轻WRS造成的黏膜损伤,GMBF、黏膜NO含量增相应增加;GMBF、UI、黏膜NO含量变化之间有相关关系。结论：内源性NO通过调节GMBF而介导耐受性细胞保护作用,L－NAME抑制其合成,延缓这一作用,L－Arg增加其合成,促进该作用。     

应激状态下大鼠胃黏膜组织中内皮素-1A受体mRNA的表达及其意义

应激性溃疡(SU)是危重疾病的常见严重并发症,其发生机制尚不清楚。研究表明内源性缩血管因子内皮素(ET)-1与SU密切相关,而关于其受体表达在SU发生中作用的研究尚少。目的:探讨ET-1A受体(ETAR)mRNA表达在SU发生中的作用和意义。方法:以冷束缚应激(CRS)制备大鼠胃溃疡模型,应激前和应激1 h、3 h、6 h、9 h、12 h后分别采用放射免疫测定、逆转录聚合酶链反应(RT-PCR)和斑点杂交等方法,动态检测血浆和胃黏膜组织中的ET-1和胃黏膜组织中的ETAR mRNA水平,同时检测胃黏膜血流量(GMBF)和溃疡指数(UI)等指标的变化情况。结果:与正常对照组相比,各应激组大鼠血浆和胃黏膜组织中的ET-1水平均显著升高(P<0.05),GMBF显著下降(P<0.01),UI显著增加(P<0.01);胃黏膜组织中的ET-1水平与UI呈显著正相关(r=0.98,P<0.01),与GMBF呈显著负相关(r=-0.89,P<0.05),而血浆ET-1水平与GMBF、UI相关性不显著(r=-0.61,0.43,P>0.05)。GMBF与UI呈显著负相关(r=-0.98,P<0.01)。RT-PCR和斑点杂交显示各应激组大鼠胃黏膜组织中ETAR mRNA的表达水平较正常对照组显著升高(P<0.01),并与胃黏膜组织中的ET-1水平和UI呈显著正相关(r=0.93,0.95,P<0.01)。结论:在CRS诱发大鼠急性胃黏膜损伤的过程中,胃黏膜组织可显著增加ET-1的合成分泌和ETAR mRNA的     

Effect of acupuncture at Foot-Yangming Meridian on gastric mucosal blood flow, gastric motility and brain-gut peptide

AIM： To observe the effect of acupuncture at Foot- Yangming Meridian on gastric mucosal blood flow （GMBF）, gastric motility and brain-gut peptide.
METHODS： Sixty SD rats were randomly divided into 6 groups： normal control group, model group （group with gastric mucosal damage, GMD）, Sibai group （with acupuncture at Sibai point ＋ GMD）, Tianshu group （with acupuncture at Tianshu point ＋ GMD）, Zusanli group （with acupuncture at Zusanli point ＋ GMD） and non-acupoint group （with acupuncture at non-acupoint ＋ GMD）. The GMD model group was induced by infusing pure alcohol into gastric cavity. H2 Gas Clearance Test （HGCT） was used to measure GMBF, the frequency and amplitude of gastric motility were measured by the method of aerocyst, the content of brain-gut peptide in sinus ventriculi and bulbus medullae were detected by radioimmunoassay.
RESULTS： Inhibitory effect of the frequency and amplitude of gastric motility were shown in model group, and the rates of frequency and amplitude changes were remarkably different from the normal control group （-19.41 ± 17.21 vs-4.71 ± 10.32, P 〈 0.05; -51.61 ± 29.02 vs 1.81 ± 14.12, P 〈 0.01）. In comparison with control group, the GMBF was 0.52 ± 0.161 mL vs 1.03 ± 0.255 mL per 100g tissue/min, P 〈 0.01, the content of motilin in sinus ventriculi and bulbus medullae was 63.04 ± 7.77 pg/mL vs 72.91 ± 8.42 pg/mL, P 〈 0.05 and 50.96 ± 8.77 pg/mL vs 60.76 ± 8.05 pg/mL, P 〈 0.05, but the content of somatostatin in sinus ventriculi and bulbus medullae was 179.85 ± 43.13 ng/g vs 90.54 ± 40.42 ng/g, P 〈 0.01 and 532.86 ± 122.58 ng/g vs 370.91 ± 76.29 ng/g, P 〈 0.05,respectively. In comparison with model group, the amplitude of gastric motility was 1.52 ± 20.13, -6.52 ± 23.31, 6.92 ± 25.21 vs -51.61 ± 29.02, P 〈 0.01 and GMBF was 0.694 ± 0.160 mL vs 0.893 ± 0.210 mL, 1.038 ± 0.301 mL vs 0.52 ± 0.161 mL per 100g tissue/rain, P 〈 0.01, respectively in Tianshu, Sibai and Zusanli groups, the content of moti     

Correlation between expression of cyclooxygenase-2 and angiogenesis in human gastric adenocarcinoma

AIM: To evaluate the expression of cyclooxygenase (COX2) and the relationship with tumor angiogenesis and advancement in gastric adenocarcinoma.METHODS: Immunohistochemical stain was used for detecting the expression of COX-2 in 45 resected specimens of gastric adenocarcinoma; the monoclonal antibody against CD34 was used for displaying vascular endothelial cells, and microvascular density (MVD) was detected by counting of CD34-positive vascular endothelial cells. Paracancerous tissues were examined as control.RESULTS: Immunohistological staining with COX-2-specific polyclonal antibody showed cytoplasmic staining in the cancer cells, some atypical hyperplasia and intestinal metaplasia,as well as angiogenic vasculature present within the tumors and prexisting vasculature adjacent to cancer lesions. The rate of expression of COX-2 and MVD index in gastric cancers were significantly increased, compared with those in the paracancerous tissues (77.78 vs 33.33 %, 58.13±19.99 vs 24.02±10.28, P＜0.01, P＜0.05, respectively). In 36 gastric carcinoma specimens with lymph node metastasis, the rate of COX-2 expression and MVD were higher than those in the specimens without metostasis (86.11 vs 44.44 %,58.60±18.24 vs 43.54±15.05, P＜0.05, P＜0.05, respectively).The rate of COX-2 expression and MVD in the specimens with invasive serosa were significantly higher than those in the specimens without invasion to serosa (87.88 vs 50.0 %,57.01±18.79 vs42.35±14.65, P＜0.05, P＜0.05). Moreover,MVD in COX-2-positive specimens was higher than that in COX-2-negative specimens (61.29±14.31 vs 45.38±12.42,P＜0.05). COX-2 expression was positively correlated with MVD (r=0.63, P＜0.05).CONCLUSION: COX-2 expression might correlate with the occurance and advancement of gastric carcinoma and is involved in tumor angiogenesis in gastric carcinoma. It is likely that COX-2 by inducing angiogenesis can be one of mechanisms which promotes invasion and metastasis of gastric carcinoma. It may become a new therapeutic target for anti-angiogenesis.     

GABAergic Mechanisms of Gastroprotection in the Rat: Role of Sensory Neurons, Prostaglandins, and Nitric Oxide

gamma-Aminobutyric acid (GABA) is a neurotransmitter found in both the central and the peripheral nervous systems including the gastrointestinal tract. The aims of the present studies were to examine mechanisms by which GABA exerts gastroprotective effects against ethanol- and water-restraint stress (WRS)-induced gastric mucosal injury in the rat. GABA, administered intragastrically (400 mg/kg), induced gastroprotection against ethanol and WRS by activating gastric sensory neurons to release calcitonin gene-related peptide (CGRP) and promote nitric oxide (NO) synthesis and release. Furthermore, these protective effects of GABA were associated with an increase in gastric mucosal blood flow (GMBF) that was dependent on sensory neuron and NO systems. GABA-mediated protection involved GABAA receptor activation and prostaglandin generation. In conclusion, intraluminal GABA protects the stomach against ethanol- and WRS-induced injury by mechanisms which involve sensory neuron/CGRP/NO pathways and increases in GMBF and prostaglandin generation.     

Effects of acute normovolemic anemia on gastric mucosal blood flow in rats: role of nitric oxide.

The present study investigates the effects of acute normovolemic anemia induced by isovolemic hemodilution on gastric mucosal blood flow (GMBF), measured by hydrogen gas clearance, and on the oxygen and hemoglobin content in the gastric mucosa, estimated by reflectance spectrophotometry. GMBF significantly increased after 3 and 6 mL of isovolemic hemodilution (from 50 +/- 5 to 70 +/- 7 and 77 +/- 6 mL.min-1.100 g-1, respectively; P less than 0.05) compared with basal values (50 +/- 5.mL-1.min-1.100 g-1; P less than 0.05). Oxygen content remained unchanged, whereas hemoglobin concentration decreased in parallel with the decrease in hematocrit. In a second set of experiments, the role of endogenous nitric oxide (NO) as a possible mediator of the gastric vascular changes induced by hemodilution was investigated by using the specific inhibitor of NO biosynthesis, NG-monomethyl-L-arginine (L-NMMA). The increase in GMBF induced by 3 mL of isovolemic hemodilution (delta 23 +/- 7 mL.min-1.100 g-1) was attenuated in a dose-related manner with L-NMMA, 6.25 mg/kg IV (delta 15 +/- 4 mL.min-1.100 g-1) or 50 mg/kg IV (delta 5 +/- 2 mL.min-1.100 g-1 g; P less than 0.05). The concurrent administration of L-arginine (the precursor of NO biosynthesis) abolished the effects of L-NMMA on GMBF changes. The current findings show that acute normovolemic anemia causes an increase in GMBF that is dependent on the endogenous formation of NO.     

Ameliorative effects of sodium ferulate on experimental colitis and their mechanisms in rats

AIM: To investigate the ameliorative effects of sodium ferulate (SF) on acetic acid-induced colitis and their mechanisms in rats.METHODS: The colitis model of Sprague-Dawley rats was induced by intracolon enema with 8 % (WV) of acetic acid.The experimental animals were randomly divided into model control, 5-aminosalicylic acid therapy group and three dose of SF therapy groups. The 5 groups were treated intracolonically and daily (8:00 am) for 7 days 24 h following the induction of colitis. A normal control group of rats clystered with normal saline instead of acetic acid was also included in the study.Pathological changes of the colonic mucosa were evaluated by the colon mucosa damage index (CMDI) and the histopathological score (HS). The insulted colonic mucosa was sampled for a variety of determinations at the end of experiment when the animals were sacrificed by decapitation.Colonic activities of myeloperoxidase (MPO) and superoxide dismutase (SOD), and levels of malondialdehyde (MDA)and nitric oxide (NO) were assayed with ultraviolet spectrophotometry. Colonic contents of prostaglandin E2 (PGE2) and thromboxane B2 (TXB2)were determined by radioimmunoassay. The expressions of inducible nitric oxide synthase (iNOS), cyclo-oxygenase-2 (COX-2) and nuclear factor kappa B (NF-κB) p65 proteins in the colonic tissue were detected with immunohistochemistry.RESULTS: Enhanced colonic mucosal injury, inflammatory response and oxidative stress were observed in the animals clystered with acetic acid, which manifested as the significant increase of CMDI, HS, MPO activities, MDA and NO levels,PGE2 and TXB2 contents, as well as the expressions of iNOS,COX-2 and NF-κB p65 proteins in the colonic mucosa,although the colonic SOD activity was significantly decreased compared with the normal control (CMDI: 2.9±0.6 vs0.0±0.0;HS: 4.3±0.9 vs0.7±1.1; MPO: 98.1±26.9 vs24.8±11.5; MDA:57.53±12.36 vs9.21±3.85; NO: 0.331±0.092 vs0.176±0.045;PGE2: 186.2±96.2 vs 42.8±32.8; TXB2: 34.26±13.51 vs 8.83±3.75; iNOS: 0.365±0.026 vs0.053±0.015; COX-2:0.296±0.028 vs0.034±0.013; NF-κB p65:0.314±0.026 vs 0.039±0.012; SOD: 28.33±1.17 vs36.14±1.91; P<0.01).However, these parameters were found to be significantly ameliorated in rats treated locally with SF at the given dose (CMDI: 1.8±0.8, 1.6±0.9; HS: 3.3±0.9, 3.1±1.0; MPO:63.8±30.5, 36.2±14.2; MDA: 41.84±10.62, 37.34±8.58; NO:0.247±0.042; 0.216±0.033; PGE2: 77.2±26.9, 58.4±23.9;TXB2:18.07±14.83; 15.52±8.62; iNOS:0.175±0.018, 0.106±0.019;COX-2: 0.064±0.018, 0.056±0.014; NF-κBp65: 0.215±0.019,0.189±0.016; SOD: 32.15±4.26, 33.24±3.69; P<0.05-0.01).amelioration of colonic mucosal injury as evaluated by CMDI and HS.CONCLUSION: Administration of SF intracolonically may have significant therapeutic effects on the rat model of colitis induced by acetic acid enema, which was probably due to the mechanism of antioxidation, inhibition of arachidonic acid metabolism and NF-κB expression.     

Characteristics of familial juvenile polyps expressing cyclooxygenase-2

OBJECTIVES: Familial juvenile polyposis (FJP) is a dominant genetic disorder characterized by colorectal, gastric, and small bowel juvenile polyps, and high risk for gastrointestinal cancer. Patients are treated by repeated endoscopic polypectomies and elective surgery. We determined the characteristics of FJP polyps expressing cyclooxygenase-2 (COX-2). METHODS: A total of 115 colorectal and 6 gastric polyps were available from 17 FJP patients. Comparison tissues were 18 sporadic juvenile colorectal polyps, 6 gastric hyperplastic polyps, 9 normal colons, and 3 colorectal cancers (CRCs). Histology sections were classified and stained for COX-2. The polyps' epithelium and stroma and comparison tissues were quantified for COX-2 by: area of staining (0-3) x intensity (0-3). Epithelial and stromal scores (0-9) and total scores (0-18) were evaluated in relationship to patient's age, polyp site, size, dysplasia, and stromal cellularity. RESULTS: Colonic FJP polyps mean total COX-2 score was 10.3 +/- 6.0, and that of sporadic juvenile polyps 3.6 +/- 2.2 (p < 0.01), and in contrast to the latter, FJP COX-2 scores increased significantly (p < 0.01) with polyp size. Linear regression analysis showed significant associations of COX-2 in FJP polyps with dysplasia (p < 0.01), stromal cellularity (p < 0.01), size (> or =1.5 cm) (p= 0.02), and site (right colon) (p= 0.01), and not with age. COX-2 total scores of gastric FJP polyps and hyperplastic polyps were similar. CONCLUSIONS: Expression of COX-2 in FJP polyps and its association with size and dysplasia suggest that, in these patients, chemoprevention with selective COX-2 inhibitors might be a useful adjunct therapy to colonoscopic polypectomy.     

Effects of melatonin on the expression of iNOS and COX－2 in rat models of colitis

AIM: To investigate the effects of melatonin (MT) on the expression of inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2) in rat models of colitis. METHODS: Healthy adult Sprague-Dawlay (SD) rats of both sexes, weighing 280+/-30 g, were employed in the present study. The rat models of colitis were induced by either acetic acid or 2,4,6-trinitrobenzene sulfonic acid (TNBS) enemas. The experimental animals were randomly divided into melatonin treatment and model control group that were intracolicly treated daily with melatonin at doses of 2.5, 5.0, 10.0 mg/kg(-1) and equal amount of saline respectively from 24 h following induction of colitis in rats inflicted with acetic acid enema and the seventh day in rats with TNBS to the end of study. A normal control group of rats treated with neither acetic acid nor TNBS but saline enema was also included in the study. On the 28(th) day of the experiment, the rat colon mucosal damage index (CDMI) was calculated, and the colonic prostaglandin E(2) (PGE(2)), nitric oxide (NO), as well as the iNOS and COX-2 expression were also determined biochemically or immunohistochemically. RESULTS: CDMI increased to 2.87+/-0.64 and 3.12+/-1.12 respectively in rats treated with acetic acid and TNBS enema, which was in accordance with the significantly elevated colonic NO and PGE(2) contents, as well as the up-regulated colonic iNOS and COX-2 expression in both of the two rat models of colitis. With treatment by melatonin at the doses of 5.0 and 10.0 mg/kg(-1), CDMI in both models of rat colitis was significantly decreased (P<0.05-0.01), which accorded synchronously and unanimously with the reduced colonic NO and PGE(2) content, as well as the down-regulated expression of colonic iNOS and COX-2. CONCLUSION: Melatonin has a protective effect on colonic injury induced by both acetic acid and TNBS enemas, which is probably via a mechanism of local inhibition of iNOS and COX-2 expression in colonic mucosa.     

Expression of COX‐1, COX‐2 and inducible nitric oxide synthase in superficial gastritis,mucosal dysplasia and gastric carcinoma

OBJECTIVE : To investigate the significance of the expression of cyclooxygenase‐1 (COX‐1), cyclooxygenase‐2 (COX‐2) and inducible nitric oxide synthase (iNOS) in superficial gastritis, gastric mucosal dysplasia and gastric carcinoma, and to study the relationship between COX‐2, iNOS, gastric carcinoma and Helicobacter pylori infection. METHODS : Polyclonal antibodies to COX‐1, COX‐2 and iNOS were used detect their expression and the status of H. pylori infection in 92 specimens of paraffin‐embedded gastric tissue. Of the 92 patients, 33 had superficial gastritis, 30 had gastric mucosal dysplasia and 29 had gastric cancer. Helicobacter pylori was detected by toluidine blue staining. RESULTS : Expression of COX‐2 and iNOS in gastric cancer (65.5%, 62.1%) was significantly higher than that in gastritis (18.2%, 18.2%; P < 0.01). Expression of COX‐2 and iNOS in gastritis with H. pylori infection was higher than that in gastric mucosal dysplasia with H. pylori infection. The expression of COX‐2 and iNOS occurred concomitantly in gastritis, dysplasia and gastric cancer. CONCLUSION : Inflammation and H. pylori infection may be able to stimulate the expression of COX‐2 and iNOS, which might be involved in gastric carcinogenesis.     

不同抗溃疡药物对应激性溃疡发生、发展过程中细胞凋亡的影响

背景：研究不同抗溃疡药物在防治应激性溃疡(SU)时，其对胃黏膜细胞学行为的作用是否有助于SU的防治。目的：观察抗溃疡药物奥美拉陛、米索前列醇和铝碳酸镁对SU的疗效，及其对细胞凋亡和与凋亡相关的细胞因子一氧化氮合酶(NOS)表达的影响。方法：水浸—束缚应激(WRS)结束后2h，计算胃黏膜损伤的溃疡指数(UI)；原位末端标记(TUNEL)法检测胃黏膜细胞凋亡；免疫组化法检测神经型NOS(nNOS)和诱导型NOS(iNOS)表达的变化。结果：奥美拉陛(0)组、米索前列醇(M)组和铝碳酸镁(H)组胃黏膜损伤均较生理盐水组显著减轻(P＜0．01)，胃黏膜细胞凋亡发生率均显著降低(P＜0．01)，但0组和M组的效果优于H组。与生理盐水组比较，3组用药组的nNOS表达均显著增加(P＜0．01)，iNOS表达均显著降低(P＜0．01)，M组和H组的nNOS表达升高较0组更为显著(P＜0．05)。结论：奥美拉唑、米索前列醇和铝碳酸镁作用于SU发生的不同环节，可显著抑制细胞凋亡的发生，对SU均有明显防治作用。寻找对细胞有直接保护作用的药物以提高细胞的抗应激能力可能是防治SU的最终途径。     

Changes of gastric and intestinal blood flow, serum phospholipase A2 and interleukin-1β in rats with acute necrotizing pancreatitis

AIM: To explore the relationship between gastric and intestinal microcirculatory impairment and inflammatory mediators released in rats with acute necrotizing pancreatitis (ANP). METHODS: A total of 64 rats were randomized into control group and ANP group. ANP model was induced by injection of 5% sodium taurocholate under the pancreatic membrane. Radioactive biomicrosphere technique was used to measure the gastric and intestinal tissue blood flow at 2 and 12 h after the induction of ANP, meanwhile serum phospholipase A2 (PLA2) activities and interleukin-lβ levels were determined. Pathologic changes in pancreas, gastric and intestinal mucosae were studied. RESULTS: The gastric blood flow in ANP group (0.62&#177;0.06and 0.35&#177;0.05) mL/(min&#183;g) was significantly lower than that in control group (0.86&#177;0.11 and 0.85&#177;0.06) mL/(min&#183;g) (P&lt;0.01) at 2 and 12 h after induction of ANP. The intestinal blood flow in ANP group (0.80&#177;0.07 and 0.50&#177;0.06) mL/(min&#183;g) was significantly lower than that in control group (1.56&#177;0.18 and 1.61&#177;0.11) mL/(min&#183;g) (P&lt;0.01). Serum PLA2 activities (94.29&#177;9.96 and 103.71&#177;14.40) U/L and IL-Iβ levels (0.78&#177;0.13 and 0.83&#177;0.20) μg/Lin ANP group were higher than those in control group (65.27&#177;10.52 and 66.63&#177;9.81) U/L, (0.32&#177;0.06 and 0.33&#177;0.07)μg/L (P&lt;0.01). At 2 and 12 h after introduction of the model, typical pathologic changes were found in ANP. Compared with control group, the gastric and intestinal mucosal pathologic changes were aggravated significantly (P&lt;0.01) at 12 h after induction of ANP. Gastric and intestinal mucosal necrosis, multiple ulcer and hemorrhage occurred. CONCLUSION: Decrease of gastric and intestinal blood flow and increase of inflammatory mediators occur simultaneously early in ANP, both of them are importantpat hogenic factors for gastric and intestinal mucosal injury in ANP.