人胃癌组织中一氧化氮合酶的表达

目的探讨NOS与胃癌的关系.方法用NADPH-d组织化学法测定了正常胃组织、癌旁组织和癌组织中一氧化氮合酶(NOS)表达水平.结果正常胃组织中粘膜上皮细胞、各种有分泌功能的细胞及肌层神经纤维中均有NOS表达,测一个视野NOS阳性细胞的平均灰度,正常胃组织为112、癌旁组织为120、胃癌组织为145.各组间差异有显著意义.表明正常胃组织NOS活性最高,胃癌组织NOS活性最低.结论①正常胃组织有广泛的NOS分布,提示NO对维持正常胃功能具有重要作用;②胃粘膜细胞癌变过程中,NOS活性明显降低,提示NOS活性与胃粘膜细胞癌变有高度相关性.     

Role of neuronal nitric oxide synthase and inducible nitric oxide synthase in intestinal injury in neonatal rats

AIM: To investigate the dynamic change and role of neuronal nitric oxide synthase (nNOS) and inducible nitric oxide synthase (iNOS) in neonatal rat with intestinal injury and to define whether necrotizing enterocolitis (NEC) is associated with the levels of nitric oxide synthase (NOS) in the mucosa of the affected intestine tissue. METHODS: Wistar rats less than 24 h in age received an intraperitoneal injection with 5 mg/kg lipopolysaccharide (IPS). Ileum tissues were collected at 1, 3, 6, 12 and 24 h following LPS challenge for histological evaluation of NEC and for measurements of nNOS and iNOS. The correlation between the degree of intestinal injury and levels of NOS was determined. RESULTS: The LPS-injected pups showed a significant increase in injury scores versus the control. The expression of nNOS protein and mRNA was diminished after LPS injection. There was a negative significant correlation between the nNOS protein and the grade of median intestinal injury within 24 h. The expression of iNOS protein and mRNA was significantly increased in the peak of intestinal injury. CONCLUSION: nNOS and iNOS play different roles in LPS-induced intestinal injury. Caution should be exerted concerning potential therapeutic uses of NOS inhibitors in NEC.     

Distribution of nitric oxide synthase in stomach wall in rats

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肝癌组织中一氧化氮合酶及其基因表达的研究

目的研究肝癌组织中一氧化氮合酶(iNOS)及其基因表达与肝癌发生发展的关系。方法用免疫组化和原位杂交的方法对21例肝癌及癌旁组织中的诱导型一氯化氮合酶(iNOS)及其基因表达进行原位检测和观察。结果:NOS 阳性反应物质呈黄色或棕黄色,位于细胞浆中。非癌殖织(肉眼观距癌组织边缘>1.5)多呈阴性或弥漫弱阳性,但部分非癌组织中可见 iNOS 呈阳性的细胞呈点状分布;癌旁组织多呈阳性,提示 iNOS 表达与肝组织癌变有关。癌组织核心多呈阴性或弥漫弱阳性,但分化中和差的癌组织核心也分别有一例 NOS 呈强阳性;周边癌组织呈局灶阳性,侵入纤维组织中的弥敢癌细胞星强阳性,提示 NOS 的表达与肝癌组织的侵润能力有关。肝癌组织 iNOSmRNA 阳性细胞的分布与 iN-OS 蛋白的表达基本相似。结论 iNOS 蛋白及其基因表达与肝组织癌变及肝癌侵润能力有关。     

Expression of inducible nitric oxide synthase activity in human colon epithelial cells: modulation by T lymphocyte derived cytokines

Background—Nitricoxide (NO) synthesis and inducible nitric oxide synthase (iNOS)expression are increased in colonic biopsy specimens from patients withulcerative colitis, but the cellular source of NO production is not known.
Aims—To examine thedistribution of iNOS in human colonic mucosa and to explore the abilityof T lymphocyte derived cytokines to regulate iNOS expression andactivity in human colonic epithelial cells.
Methods—iNOSexpression was examined using immunohistochemistry in colonic biopsysamples from 12 patients with ulcerative colitis and three withinfectious colitis and compared with 10normal controls. In vitro iNOSexpression and activity were determined in HT-29 cell cultures; nitritelevels were measured using a fluorescent substrate, iNOS mRNAexpression by northern blot analysis, and iNOS protein expression bywestern blot analysis.
Results—No iNOSexpression was detected (10 of 10) in non-inflamed mucosa derived fromnormal controls. In 11 of 12 cases of newly diagnosed ulcerativecolitis, iNOS protein was expressed in the epithelial cells, while noother positive cells were found in the lamina propria. Similar iNOSlabelling was found in colonic biopsy samples from patients withinfectious colitis in the acute phase, but when re-examined in samplesfrom patients in total remission, no iNOS staining was observed. Bothinterleukin (IL)-13 and IL-4, but not IL-10, are potent inhibitors ofiNOS expression and activity induced by an optimal combination ofcytokines, namely IL-1α, tumour necrosis factor α and interferonγ.
Conclusions—The datasuggest that the epithelium is the major source of iNOS activity inulcerative colitis and that IL-13 and IL-4 may act as intrinsicregulators of NO generation in intestinal inflammation.

Keywords:interleukin 13; nitric oxide; inducible nitric oxidesynthase; colonic epithelial cells; ulcerative colitis

     

Distribution of nitric oxide synthase in stomach myenteric plexus of rats

AIM:To study the distribution of nitdc oxide synthese(NOS)in rat stomach myenteric plexus.METHODS:The distribution of NOS in gastric wall wasstudied in quantity and location by the NADPH-diaphorase(NDP)histochemical staining method and whole mountpreperation technique.RESULTS:NOS was distributed in whole stomach wall,mostof them were located In myenteric plexus,and distributed insubmucosal plexus.The shape of NOS positive neuronswas baslcally similar,most of them being round and oval inshape.But their density,size and staining intensity variedgreatly in the different parts of stomach.The density was 62±38 cells/mm~2(antrum),43±32 cells/mm~2(body),and 32±28 cells/mm~2(fundus),respectively.The size andstaining intensity of NOS positive neurons in the funduswere basically the same,the neurons being large and darkstained,while they were obviously different in antrum.Inthe body of the stomach,the NOS positive neurons were inan Intermediate state from fundus to antrum.There weresome beedlike structures which were strung together byNOS positiva varicosities in nerve fibers,some were closelyadherent to the outer walls of blood vessels.CONCLUSION:Nitric oxide might he involved in themodulation of motility,secretion and blood circulation ofthe stomach,and the significant difference of NOS positiveneurons in different parts of stomach myenteric plexus maybe related to the physiologic function of stomach.     

Expression of inducible nitric oxide synthase in cultured smooth muscle cells from rat mesenteric lymphatic vessels

OBJECTIVE: The objective was to devise a method for establishing cultures of rat mesenteric lymphatic vessel smooth muscle cells (LSMC) and to investigate if inducible nitric oxide synthase (iNOS) expression could be activated in LSMC treated with bacterial lipopolysaccharide (LPS). METHODS: LSMC were successfully grown from explanted rat lymphatic microvessels and maintained by subculture. Treatment of LSMC for 24 h with LPS (1-100 microg/mL) activated iNOS protein induction, associated with (1) assay of increased nitrite concentrations in the medium representing cellular nitric oxide synthesis, and (2) demonstration of iNOS in cell extracts by Western blotting. RESULTS: The protein synthesis inhibitor cycloheximide (10 microM) blocked both LPS-induced nitrite formation and iNOS protein expression in LSMC. 1400 W (1 microM), a selective iNOS inhibitor, prevented LPS-induced nitrite formation but not iNOS expression. As well as induction of iNOS by LPS, "constitutive" iNOS was present in some cultures, producing nitrite in amounts that were also subsequently reduced after cell treatment with 1400 W. CONCLUSION: Rat mesenteric LSMC produce nitrite and express iNOS in response to bacterial LPS. Cultured LSMC may provide a useful model for studying mechanisms of iNOS induction in relation to possible influences of iNOS upon lymphatic vessel function.     

Early effects of diabetes on inducible nitric oxide synthase in the kidney

NO may be responsible for the glomerular hyperfiltration observed in diabetic kidney by inducing vasodilation of the afferent arteriole. The aim of this study was to evaluate which isoform of nitric oxide synthase (NOS) is responsible for increased renal production of NO in diabetic kidney. Thirty male WKY rats were divided into 6 groups. Five rats were sacrificed immediately, five after 20 days. In the other rats, diabetes was induced by streptozotocin. The four diabetic groups were sacrificed respectively after 5, 10, 15 and 20 days. Urine excretion of NO metabolites was assayed; immunochemistry showed the presence of inducible (iNOS) and endothelial constitutive (ecNOS) synthases in the kidney. Urinary excretion of NO metabolites increased significantly in diabetic rats five days after the induction of diabetes and at the end of the study whereas it was unchanged in the control group. Renal ecNOS remained unchanged throughout the study in all rats whereas iNOS increased significantly in diabetic rats from the fifth day until the end of the study. The results demonstrate that iNOS is activated in the kidney of rats, soon after the induction of diabetes, thus suggesting its involvement in the increased production of NO observed immediately after the onset of diabetes. Received: 19 September 2001 / Accepted in revised form: 31 January 2002     

Role of cyclooxygenase-2 and inducible nitric oxide synthase in pancreatic cancer

BACKGROUND AND AIM: Recently, it has been recognized that both cyclooxygenase-2 (COX-2) and inducible nitric oxide synthase (iNOS) produce important endogenous factors of human tumor progression. However, the clinicopathological and biological significance of the expression of COX-2 and iNOS in pancreatic cancer remains unclear. The objective of this study is to find the possible roles and clinical significance of COX-2 and iNOS expression in pancreatic cancer. METHODS: Seventy-two pancreatic adenocarcinoma tissue specimens were obtained through surgical resection. We investigated the immunohistochemical expression of COX-2 and iNOS in respect to variable clinicopathological characteristics, proliferation activity (by Ki-67 expression), apoptosis (by terminal deoxyribonucleotidyl transferase-mediated dUTP nick-end labeling stain), and microvessel density (by CD34 expression; angiogenesis). RESULTS: Immunohistochemical investigations demonstrated immunolabeling of tumor cells with the primary antibodies, bovine anti-iNOS and anti-COX-2 antibodies. The COX-2 and iNOS positive rates were 41.7 and 66.7%, respectively. There was significant correlation between positive COX-2 and positive iNOS expression (P = 0.043). The proliferation index (Ki-67 labeling index) was higher in COX-2 positive specimens compared to COX-2 negative specimen (P = 0.015). The apoptotic index of positive iNOS expressions was significantly higher than negative expressions (P < 0.001). The expression of COX-2 and iNOS proteins did not correlate with age, sex, serum bilirubin, CA-19-9, location, size, American Joint Committee on Cancer stage, differentiation, distant metastasis, patient survival, or microvessel density. CONCLUSIONS: Although the pattern of positive expression was similar in both enzymes, the effect on tumor progression differed; iNOS expression may play a role in apoptosis of tumor cell, while COX-2 expression may contribute to tumor proliferation. However, COX-2 and iNOS expression is not related to prognosis in patients with pancreatic cancer.     

The plasma level of nitric oxide and the expression of inducible nitric oxidesynthase in human hepatocellular carcinoma

AIM To study the relationship between nitric oxide (NO), nitric oxide synthase (NOS) and humanhepatocellular carcinoma (HCC).METHODS Plsama NO2-/NO3- was measured by Griess reaction in 122 patients with chronic hepatitis(CH) and compensated liver cirrhosis (LC), among which 62 patients were complicated with HCC(CH = 28, LC = 34), and the rest 60 patients were not (CH = 29, LC = 31). Thirty healthy persons served asnormal controls (NC). There were no prominent differences among the groups in sex, age and the ratio ofCH to LC. The expression of inducible nitric oxide synthase (iNOS) in HCC (n = 40), CH (n = 30) and LC(n = 30) samples obtained from liver biopsy or operation was compared with that in normal liver tissues byusing immunohistochemistry. Ten normal liver tissue samples obtained from liver operation served as normalcontrols. The samples were fixed in formalin and embeded in paraffin. Anti-iNOS antibody (Santacruzcompany) was served as antibody-Ⅰ in immunohistochemical assay of iNOS in tissue.RESULTS Plasma NO2-/NO3- level in normal was 11.5 μmol/L±4.2μmol/L. The plasma level ofNO2 /NO3- in CH (58.6±17.4 μmol/L) and LC (38.7±10.6μmol/L) accompanied with HCC wasnotably higher than in those patients without HCC (CH: 24.8±9.4 μmol/L; LC: 22.3±8.7μmol/L,t=2.901, 2.756, P<0.01). Plasma NO2-/NO3- level in HCC accompanied with CH was significantlyhigher than in those accompanied with LC ( t = 2.216, P<0.05). Positive rate of iNOS in HCC, CH and LCwas 95%, 93% and 57% respectively. iNOS was not expressed in normal liver tissues. The expression level ofiNOS in HCC (χ2=17.4, P<0.001) and CH (χ2=11.64, P<0.025) was much higher than in LC.CONCLUSION Plasma NO2 / NO3- level significantly increased in patients with HCC and theimmunohistochemical staining of iNOS was positive. This suggests that the liver secrets NO in the higherlevel may participate in the carcinogenesis and progression of HCC.     

诱导型一氧化氮合酶在创伤性脑损伤后肠黏膜屏障损伤中表达的变化

目的观察创伤性脑损伤（TBI）后肠黏膜屏障损伤时诱导型一氧化氮合酶（iNOS）表达的变化及其可能的作用。方法 48只健康雄性W istar大鼠随机分为TBI组（n=24）和对照组（n=24）,各组动物分别在手术后3、6、12、24 h处死,每个时间点6只。动物处死后,抽门静脉血测血清内毒素、二胺氧化酶（DAO）,取脑组织和回肠黏膜,观察组织形态学改变,并测定肠黏膜组织DAO的含量和iNOS的表达情况。结果 TBI组肠黏膜受损,血中内毒素含量增加（P〈0.05）;肠黏膜DAO活性下降（P〈0.01）,而血中DAO活性则升高（P〈0.05）;iNOS的表达3h已经增高,12h达到最高,而后逐渐降低,但仍然高于对照组（P〈0.05）。结论 iNOS在TBI后肠黏膜屏障损伤时表达明显增加,参与了TBI后肠黏膜屏障损伤。     

Temporal expression of hepatic inducible nitric oxide synthase in liver cirrhosis

AIM: Nitric oxide (NO) has been implicated in the pathogenesis of liver cirrhosis. We have found inducible nitric oxide synthase (iNOS) can be induced in hepatocytes of cirrhotic liver. This study further investigated the temporal expression and activity of hepatic iNOS in cirrhosis development. METHODS: Cirrhosis was induced in rats by chronic bile duet ligatjon (BDL). At different time points after the operation, samples were collected to examine NO concentration, liver function, and morphological changes. Hepatocytes were isolated for determination of iNOS mRNA, protein and enzymatic activity. RESULTS: Histological examination showed early cirrhosis 1-2 wk after BDL, with advanced cirrhosis at 3-4 wk. Bilirubin increased dramatically 3 d after BDL, but decreased by 47% on d 14. Three weeks after BDL, it elevated again. Systemic NO concentration did not increase significantly until 4 wk after BDL, when ascites developed. Hepatocyte iNOS mRNA expression was identified 3 d after BDL, and enhanced with time to 3 wk, but reduced thereafter. iNOS protein showed a similar pattern to mRNA expression. iNOS activity decreased from d 3 to d 7, but increased again thereafter till d 21. CONCLUSION: Hepatic iNOS can be induced in the early stage, which increases with time as cirrhosis develops. lts enzymatic activity is significantly correlated with protein expression and histological alterations of the liver, but not with systemic NO levels, nor with absolute values of liver function markers.     

Protective effect of inducible nitric oxide synthase inhibitor on pancreas transplantation in rats

AIM： To investigate the effect of inducible nitric oxide synthase inhibitor, aminoguanidine, on pancreas transplantation in rats. METHODS： A model of pancreas transplantation was established in rats. Streptozotocin-induced diabetic male Wistar rats were randomly assigned to sham-operation control group （n = 6）, transplant control group （n = 6）, and aminoguanidine （AG） treatment group （n = 18）. In the AG group, aminoguanidine was added to intravascular infusion as the onset of reperfusion at the dose of 60 mg/kg, 80 mg/kg, 100 mg/kg body weight, respectively. Serum nitric oxide （NO） level, blood sugar and amylase activity were detected. Nitric oxide synthase （NOS） test kit was used to detect the pancreas cNOS and inducible NOS （iNOS） activity. Pancreas sections stained with HE and immunohistochemistry were evaluated under a light microscope. RESULTS： As compared with the transplant control group, the serum NO level and amylase activity decreased obviously and the evidence for pancreas injury was much less in the AG group. The AG （80 mg/kg body weight） group showed the most significant difference in NO and amylase （NO： 66.0 ± 16.6 vs 192.3 ± 60.0, P 〈 0.01 and amylase： 1426 ± 177 vs 4477± 630, P 〈 0.01）. The expression and activity of tissue iNOS, and blood sugar in the AG （80 mg/kg body weight） group were much lower than those in the transplant control group （iNOS： 2.01 ± 0.23 vs 26.59 ±5.78, P 〈 0.01 and blood sugar： 14.2 ±0.9 vs 16.8 ± 1.1, P 〈 0.01）. CONCLUSION： Selective iNOS inhibitor, aminoguanidine as a free radical, has a protective effect on pancreas transplantation in rats by inhibiting NO and reducing its toxicity.     

Inhibition of matrix metalloproteinases and inducible nitric oxide synthase by andrographolide in human osteoarthritic chondrocytes

Objective

The aim of this study was to investigate the effects of andrographolide on matrix metalloproteinases (MMP) 1, 3, and 13 and inducible nitric oxide synthase (iNOS) in human articular chondrocytes from osteoarthritic cartilage.

Methods

Passaged chondrocytes were pretreated with or without andrographolide for 2 h, followed by coincubation with interleukin-1 beta (IL-1β) 1 ng/ml for 24 h. Expression levels of MMP-1, 3, and 13, tissue inhibitor of metalloproteinase-1 (TIMP-1), and iNOS were evaluated using real-time-quantitative polymerase chain reaction, enzyme-linked immunosorbent assay, and Western blotting. Nitric oxide (NO) was analyzed using the Griess reaction assay. Involvement of nuclear factor kappa B (NF-κB) was assessed by Western blotting, transient transfection, and luciferase reporter assay.

Results

Andrographolide tested in these in vitro studies was found be an effective antiarthritic agent, as evidenced by potent inhibition of MMP-1, 3, and 13 and iNOS expression, as well as upregulation of TIMP-1 in IL-1β-stimulated human articular chondrocytes (p < 0.05). The mechanism of andrographolide’s inhibitory effects was mediated by attenuating the activation of NF-κB in human chondrocytes in the presence of IL-1β.

Conclusions

Andrographolide was a potent inhibitor of the production of inflammatory and catabolic mediators by chondrocytes, suggesting that this natural compound may merit consideration as a therapeutic agent for treating and preventing osteoarthritis.