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Citrulline decreases hepatic endotoxin-induced injury in fructose-induced non-alcoholic liver disease: anex vivostudy in the isolated perfused rat liver. Br J Nutr 2017. [DOI: 10.1017/s0007114517001453] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
AbstractSteatosis can sensitise the liver to various challenges and favour the development of non-alcoholic fatty liver disease (NAFLD). In this context, fructose feeding promotes endotoxin translocation from the gut, contributing to disease progression via an inflammatory process. Citrulline is protective against fructose-induced NAFLD; we hypothesised that this property might be related to its anti-inflammatory and antioxidative action against endotoxin-induced hepatic injuries. This hypothesis was evaluated in a model of perfused liver isolated from NAFLD rats. Male Sprague–Dawley rats (n30) were fed either a standard rodent chow or a 60 % fructose diet alone, or supplemented with citrulline (1 g/kg per d) for 4 weeks. After an evaluation of their metabolic status, fasted rats received an intraperitoneal injection of lipopolysaccharide (LPS) (2·5 mg/kg). After 1 h, the livers were isolated and perfused for 1 h to study liver function and metabolism, inflammation and oxidative status.In vivo, citrulline significantly decreased dyslipidaemia induced by a high-fructose diet and insulin resistance. In the isolated perfused rat livers, endotoxaemia resulted in higher cytolysis (alanine aminotransferase release) and higher inflammation (Toll-like receptor 4) in livers of fructose-fed rats, and it was prevented by citrulline supplementation. Oxidative stress and antioxidative defences were similar in all three groups. Amino acid exchanges and metabolism (ammonia and urea release) were only slightly different between the three groups. In this context of mild steatosis, our results suggest that fructose-induced NAFLD leads to an increased hepatic sensitivity to LPS-induced inflammation. Citrulline-induced restriction of the inflammatory process may thus contribute to the prevention of NAFLD.
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A combination of radiosurgery and soluble tissue factor enhances vascular targeting for experimental glioblastoma. BIOMED RESEARCH INTERNATIONAL 2013; 2013:390714. [PMID: 24307995 PMCID: PMC3838847 DOI: 10.1155/2013/390714] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/28/2013] [Accepted: 09/25/2013] [Indexed: 11/17/2022]
Abstract
Radiosurgery for glioblastoma is limited to the development of resistance, allowing tumor cells to survive and initiate tumor recurrence. Based on our previous work that coadministration of tissue factor and lipopolysaccharide following radiosurgery selectively induced thrombosis in cerebral arteriovenous malformations, achieving thrombosis of 69% of the capillaries and 39% of medium sized vessels, we hypothesized that a rapid and selective shutdown of the capillaries in glioblastoma vasculature would decrease the delivery of oxygen and nutrients, reducing tumor growth, preventing intracranial hypertension, and improving life expectancy. Glioblastoma was formed by implantation of GL261 cells into C57Bl/6 mouse brain. Mice were intravenously injected tissue factor, lipopolysaccharide, a combination of both, or placebo 24 hours after radiosurgery. Control mice received both agents after sham irradiation. Coadministration of tissue factor and lipopolysaccharide led to the formation of thrombi in up to 87 ± 8% of the capillaries and 46 ± 4% of medium sized vessels within glioblastoma. The survival rate of mice in this group was 80% versus no survivor in placebo controls 30 days after irradiation. Animal body weight increased with time in this group (r = 0.88, P = 0.0001). Thus, radiosurgery enhanced treatment with tissue factor, and lipopolysaccharide selectively induces thrombosis in glioblastoma vasculature, improving life expectancy.
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Gong JH, Gong JP, Li JZ, He K, Li PZ, Jiang XW. Glycogen synthase kinase 3 inhibitor attenuates endotoxin-induced liver injury. J Surg Res 2013; 184:1035-44. [PMID: 23721934 DOI: 10.1016/j.jss.2013.04.051] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2013] [Revised: 02/05/2013] [Accepted: 04/22/2013] [Indexed: 12/01/2022]
Abstract
BACKGROUND/AIMS Endotoxin (lipopolysaccharide, LPS)-induced acute liver injury was attenuated by endotoxin tolerance (ET), which is characterized by phosphatidylinositol 3-kinase pathway/Akt signaling. Glycogen synthase kinase 3 (GSK-3) acts downstream of phosphatidylinositol 3-kinase pathway/Akt and GSK-3 inhibitor protects against organic injury. This study evaluates the hypothesis that ET attenuated LPS-induced liver injury through inhibiting GSK-3 functional activity and downstream signaling. METHODS Sprague-Dawley rats with or without low-dose LPS pretreatment were challenged with or without large dose of LPS and subsequently received studies. Serum tumor necrosis factor-alpha, interleukin-10, alanine aminotransferase, lactate dehydrogenase, and total bilirubin levels were analyzed, morphology of liver tissue was performed, glycogen content, myeloperoxidase content, phagocytosis activity of Kupffer cells, and the expression and inhibitory phosphorylation as well as kinase activity of GSK-3 were examined. Survival after LPS administration was also determined. RESULTS LPS induced significant increases of serum TNF-α, alanine aminotransferase, lactate dehydrogenase, and total bilirubin (P < 0.05), which were companied by obvious alterations in liver: the injury of liver tissue, the decrease of glycogen, the infiltration of neutrophils, and the enhancement of phagocytosis of Kupffer cells (P < 0.05). LPS pretreatment significantly attenuated these alterations, promoted the inhibitory phosphorylation of GSK-3 and inhibited its kinase activity, and improved the survival rate (P < 0.05). CONCLUSIONS ET attenuated LPS-induced acute liver injury through inhibiting GSK-3 functional activity and its downstream signaling.
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Affiliation(s)
- Jun-hua Gong
- Department of Hepatobiliary Surgery, The Second Affiliated Hospital of Chongqing Medical University, Chongqing, China
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Makarova OP, Tsyrendorjiev DD, Shkurupiy VA. Lipid peroxidation in the liver of mice during development of granulomatous inflammation after combined infection with C. albicans and M. tuberculosis. Bull Exp Biol Med 2009; 146:569-72. [PMID: 19526093 DOI: 10.1007/s10517-009-0355-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
Activity of LPO in the liver of CBA mice during the development of granulomatous inflammation after combined infection with C. albicans and M. tuberculosis was evaluated by the levels of conjugated dienes, ketodienes, conjugated trienes, and products of interactions between intermediate LPO products and 2-TBA. The content of primary and secondary LPO products peaked on days 3 and 10 after infection by C. albicans, respectively. After M. tuberculosis infection, the maximum accumulation of TBA-active LPO products in the liver was noted on day 3, while the level of primary lipid peroxides virtually did not increase. The dynamics of primary and secondary LPO products in the liver during granulomatous inflammation development was similar to that during infection of mice with C. albicans alone. Hence, the development of granulomatous inflammation induced by C. albicans or M. tuberculosis or both these agents, was associated with increased LPO activity in the liver. The dynamics of primary and secondary LPO products depended on the infectious agent or combination of agents.
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Affiliation(s)
- O P Makarova
- Center of Clinical and Experimental Medicine, Siberian Division of the Russian Academy of Medical Sciences, Novosibirsk, Russia.
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Tamandl D, Jørgensen P, Gundersen Y, Fuegger R, Sautner T, Aasen AO, Goetzinger P. Nitric oxide administration restores the hepatic artery buffer response during porcine endotoxemia. J INVEST SURG 2008; 21:183-94. [PMID: 18615315 DOI: 10.1080/08941930802130131] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
Abstract
The hepatic artery buffer response, which is lost during endotoxemia, plays a central role in the autoregulation of liver perfusion. A temporarily decreased synthesis of nitric oxide during early endotoxemia might be responsible for this dysfunction; hence exogenous administration of nitric oxide could reestablish the autoregulation of hepatic blood flow and help prevent hepatic damage later in septic shock. Fifteen pigs were treated with lipopolysaccharide +/- the nitric oxide donor nitroprusside-sodium via the portal vein. Hemodynamics were measured, and serum chemistry and liver biopsies for nitric oxide synthase expression were obtained. Lipopolysaccharide decreased arterial liver perfusion after 5 hours by 38% (p = .012), which was reversed by addition of nitroprusside (8%). Administration of nitroprusside preserved an increase of 28% in hepatic arterial upon portal vein flow reduction (p < .001). Nitroprusside maintained mRNA levels of constitutive nitric oxide synthase in liver tissue which were decreased by lipopolysaccharide (p = .026 vs. p = .114) and tempered the burst in inducible nitric oxide synthase expression at t = 3 hours. The early administration of the nitric oxide donor sodium nitroprusside during endotoxemia is able to reestablish the autoregulatory response of the hepatic artery following reduction of hepatic blood flow. This beneficial effect might help to prevent subsequent hepatic damage in the course of abdominal sepsis.
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Affiliation(s)
- Dietmar Tamandl
- Department of Surgery, Vienna General Hospital, Medical University of Vienna, Vienna, Austria
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Sass G, Shembade ND, Haimerl F, Lamoureux N, Hashemolhosseini S, Tannapfel A, Tiegs G. TNF pretreatment interferes with mitochondrial apoptosis in the mouse liver by A20-mediated down-regulation of Bax. THE JOURNAL OF IMMUNOLOGY 2007; 179:7042-9. [PMID: 17982095 DOI: 10.4049/jimmunol.179.10.7042] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Pretreatment with low doses of the proinflammatory cytokine TNF has been shown to prevent hepatocellular apoptosis and liver damage in inflammatory as well as in ischemia/reperfusion-induced liver injury. The underlying mechanisms of protection have not been elucidated so far. In this study, these mechanisms were investigated in murine hepatocyte cultures as well as in a mouse model of TNF-dependent apoptotic liver damage (galactosamine/TNF model). Our results show that pretreatment with TNF, or application of small-interfering RNA directed against the proapoptotic Bcl2 family member Bax, interfered with the onset of mitochondrial apoptosis in vivo. Knockdown of TNF-alpha-induced-protein 3 (A20) restored mitochondrial apoptosis, Bax expression, and liver damage. The underlying mechanism of protection seems to involve a cascade of events, where TNF induces the expression of A20 in hepatocytes, A20 down-modulates Bax expression by interference with transcriptional activation, and the reduced availability of Bax interferes with the onset of mitochondrial apoptosis and the ensuing apoptotic liver damage. In conclusion, we identified Bax and A20 as key players in TNF-induced protection from apoptotic liver damage. Because treatment with TNF itself might be a risk factor for patients, we propose that overexpression of A20 might represent an alternative approach for protection from inflammation related apoptotic liver damage, as well as for TNF preconditioning during transplantation.
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Affiliation(s)
- Gabriele Sass
- Institute of Experimental and Clinical Pharmacology and Toxicology, University of Erlangen-Nuremberg, Erlangen, Germany
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Koch A, Boehm O, Zacharowski PA, Loer SA, Weimann J, Rensing H, Foster SJ, Schmidt R, Berkels R, Reingruber S, Zacharowski K. Inducible nitric oxide synthase and heme oxygenase-1 in the lung during lipopolysaccharide tolerance and cross tolerance. Crit Care Med 2007; 35:2775-84. [PMID: 17901834 DOI: 10.1097/01.ccm.0000288122.24212.40] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
OBJECTIVE Pretreatment with low-dose lipopolysaccharide protects cells/organs against a subsequent lethal Gram-negative (lipopolysaccharide tolerance) or Gram-positive (cross tolerance) stimulus. We determined whether this occurs in the rat lung. The involvement of inducible nitric oxide synthase and heme oxygenase-1 was evaluated. DESIGN Laboratory study. SETTING University hospital laboratory. SUBJECTS Anesthetized male Wistar rats. INTERVENTIONS To test the hypothesis, rats received saline or lipopolysaccharide (1 mg/kg). At 2, 4, 8, 16, or 24 hrs later, blood samples and lung tissue were taken to determine messenger RNA, protein concentration, and activity of inducible nitric oxide synthase and heme oxygenase-1. In additional experiments, rats were challenged with lipopolysaccharide (1 mg/kg) and subjected to Gram-negative (lipopolysaccharide) or Gram-positive (lipoteichoic acid and peptidoglycan) shock 24 hrs later. These studies were carried out in the presence and absence of inducible nitric oxide synthase or heme oxygenase-1 inhibitors (1400W or tin protoporphyrin IX). Following 6 hrs of shock, lung tissue was taken to determine lung damage and heme oxygenase-1 concentration and activity. MEASUREMENTS AND MAIN RESULTS In the rat lung, lipopolysaccharide (1 mg/kg) induced a significant increase in inducible nitric oxide synthase protein at 8 hrs with a corresponding increase in plasma nitrate/nitrite at 8-16 hrs. Simultaneously, heme oxygenase-1 messenger RNA transcripts were observed at 8-16 hrs, and maximal expression of the protein followed (24 hrs). Pretreatment with low-dose lipopolysaccharide reduced myeloperoxidase activity (neutrophil infiltration) and wet-dry ratio (pulmonary edema) in the lungs of animals subjected to Gram-negative or Gram-positive shock, demonstrating tolerance. Pretreatment with low-dose lipopolysaccharide and the selective inducible nitric oxide synthase inhibitor 1400W reduced heme oxygenase-1 protein expression, and lung protection was abolished. Tin protoporphyrin IX did not affect heme oxygenase-1 expression, but heme oxygenase activity and lung protection were significantly reduced. CONCLUSIONS We propose that nitric oxide (most likely inducible nitric oxide synthase derived) regulates the induction of heme oxygenase-1 in the lung, which in turn plays an important part in pulmonary protection during lipopolysaccharide tolerance and cross tolerance.
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Affiliation(s)
- Alexander Koch
- Molecular Cardioprotection and Inflammation Group, Department of Anesthesia, Bristol University, Bristol, UK
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Inducible nitric oxide synthase and heme oxygenase-1 in the lung during lipopolysaccharide tolerance and cross tolerance. Crit Care Med 2007. [DOI: 10.1097/00003246-200712000-00016] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
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Storer K, Tu J, Karunanayaka A, Smee R, Short R, Thorpe P, Stoodley M. Coadministration of low-dose lipopolysaccharide and soluble tissue factor induces thrombosis after radiosurgery in an animal arteriovenous malformation model. Neurosurgery 2007; 61:604-10; discussion 610-1. [PMID: 17881975 DOI: 10.1227/01.neu.0000290909.32600.a8] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
OBJECTIVE Radiosurgery for arteriovenous malformations is limited to small lesions and may take 3 years to produce total occlusion. It has recently been shown that coadministration of low-dose lipopolysaccharide (LPS) and soluble tissue factor (sTF) selectively induces thrombosis in murine tumor models, attributable perhaps to the prothrombotic phenotype of tumor vasculature. Radiosurgery may induce changes in endothelial prothrombotic molecules similar to those found in tumors. This study aimed to determine if a similar strategy could be used to stimulate thrombus formation in an animal arteriovenous malformation model. METHODS Seventeen rats underwent creation of a carotid-to-jugular anastomosis. Animals were intravenously injected with sTF, low-dose LPS, a combination of both, or placebo 24 hours after stereotactic irradiation of the anastomosis. Control animals received both agents after sham irradiation. RESULTS Coadministration of sTF and LPS led to the formation of thrombi in up to 69% of small vessels and 39% of medium-sized vessels within the target region. The irradiated vasculature demonstrated intermediate rates of thrombosis after treatment with either sTF or LPS alone as did vessels within the fistula in the control group. Logistic regression analysis demonstrated significant associations between development of thrombi and treatment with radiation, sTF, or LPS (P < 0.005). There was no evidence of systemic thrombus formation or toxicity in any group. CONCLUSION Treatment with sTF and LPS selectively induces thrombosis of irradiated vessels in a rat model of arteriovenous malformation. Stimulation of thrombosis may improve the efficacy of radiosurgery, increasing the treatable lesion size and reducing latency.
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Affiliation(s)
- Kingsley Storer
- Prince of Wales Medical Research Institute, University of New South Wales, Sydney, Australia
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Chen L, Zhang Y, Kong X, Peng S, Tian J. Synthesis and biological evaluation of nitric oxide-releasing derivatives of oleanolic acid as inhibitors of HepG2 cell apoptosis. Bioorg Med Chem Lett 2007; 17:2979-82. [PMID: 17446070 PMCID: PMC1986654 DOI: 10.1016/j.bmcl.2007.03.068] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2006] [Revised: 03/19/2007] [Accepted: 03/22/2007] [Indexed: 11/29/2022]
Abstract
A total of 106 nitric oxide-releasing derivatives of oleanolic acid were synthesized and their effects on the inhibition of anti-Fas-mediated HepG2 cell apoptosis were evaluated in vitro. Several compounds inhibited anti-Fas-mediated HepG2 cell apoptosis in a dose-dependent manner. Within this series of compounds, 8b is the most potent inhibitor. The development of new NO-releasing derivatives of oleanolic acid may aid in the design of NO-based medicines for the intervention of human liver inflammatory diseases.
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Affiliation(s)
- Li Chen
- Center of Drug Discovery, China Pharmaceutical University, 24 Tongjiaxiang, Nanjing 210009, P.R.China
- Department of Phytochemistry, China Pharmaceutical University, 1 Shennonglu, Nanjing 210038, P.R.China
| | - Yihua Zhang
- Center of Drug Discovery, China Pharmaceutical University, 24 Tongjiaxiang, Nanjing 210009, P.R.China
- *Corresponding authors, Tel: +86-25-86635503; fax: +86-25-86635503; e-mail: or Tel: 310-206-3350; fax: 310-825-6267; e-mail:
| | - Xiangwen Kong
- Center of Drug Discovery, China Pharmaceutical University, 24 Tongjiaxiang, Nanjing 210009, P.R.China
| | - Sixun Peng
- Center of Drug Discovery, China Pharmaceutical University, 24 Tongjiaxiang, Nanjing 210009, P.R.China
| | - Jide Tian
- Department of Molecular & Medical Pharmacology, University of California Los Angeles, Los Angeles, CA 90095, USA
- *Corresponding authors, Tel: +86-25-86635503; fax: +86-25-86635503; e-mail: or Tel: 310-206-3350; fax: 310-825-6267; e-mail:
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Kuo SM, Tan CH, Dragan M, Wilson JX. Endotoxin increases ascorbate recycling and concentration in mouse liver. J Nutr 2005; 135:2411-6. [PMID: 16177205 PMCID: PMC1343533 DOI: 10.1093/jn/135.10.2411] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Sublethal exposure to Escherichia coli endotoxin [lipopolysaccharide (LPS)] attenuates the lethal effects of subsequent insults associated with oxidative stress, such as higher LPS dose, septic peritonitis, and ischemia. Because administration of the antioxidant ascorbate protects against these same insults and injection of dehydroascorbic acid (DHAA) protects against ischemia, the hypothesis that sublethal LPS increases endogenous ascorbate concentration and recycling (i.e., synthesis from DHAA) was tested. Injection of LPS [5 x 10(6) endotoxin units/kg body weight, i.p.] in mice caused a temporary inhibition of food intake, which was significant by 20 h and recovered within 3 d. LPS increased ascorbate concentration in adrenal gland, heart, kidney, and liver. LPS had similar effects in wild-type and Slc23a2+/- mice despite the latter's deficiency in the ascorbate transporter SVCT2. In liver, the ascorbate response to LPS was not accompanied by change in glutathione concentration. LPS decreased gulonolactone oxidase activity, which is rate-limiting for de novo synthesis of ascorbate from glucose, but increased the rate of DHAA reduction to ascorbate. In conclusion, sublethal endotoxin increases ascorbate recycling in liver and ascorbate concentration in liver, adrenal gland, heart, and kidney. The enhanced rate of ascorbate production from DHAA may protect these organs against the reactive oxygen species produced by subsequent, potentially lethal challenges.
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Affiliation(s)
| | | | | | - John X. Wilson
- Correspondence: Dr. John X. Wilson, Department of Exercise and Nutrition Sciences, University at Buffalo, Kimball Tower, Room 410, Buffalo, NY 14214-8028, USA. Tel: (716) 829-2941 extension 408. Fax: (716) 829-2428. E-mail:
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Rodriguez J, Specian V, Maloney R, Jourd'heuil D, Feelisch M. Performance of diamino fluorophores for the localization of sources and targets of nitric oxide. Free Radic Biol Med 2005; 38:356-68. [PMID: 15629864 DOI: 10.1016/j.freeradbiomed.2004.10.036] [Citation(s) in RCA: 53] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/12/2004] [Revised: 10/15/2004] [Accepted: 10/22/2004] [Indexed: 01/14/2023]
Abstract
An emergent approach to the detection of nitric oxide (NO) in tissues relies on the use of fluorescence probes that are activated by products of NO autoxidation. Here we explore the performance of the widely used NO probe 4,5-diaminofluorescein diacetate (DAF-2 DA) for the localization of sources of NO in rat aortic tissue, either from endogenous NO synthesis or from chemically or photolytically released NO from targets of nitrosation/nitrosylation. Of importance toward understanding the performance of this probe in tissues is the finding that, with incubation conditions commonly used in the literature (10 microM DAF-2 DA), intracellular DAF-2 accumulates to concentrations that approach the millimolar range. Whereas such high probe concentrations do not interfere with NO release or signaling, they help to clarify why DAF-2 nitrosation is possible in the presence of endogenous nitrosation scavengers (e.g., ascorbate and glutathione). The gain attained with such elevated concentrations is, however, mitigated by associated high levels of background autofluorescence from the probe. This, together with tissue autofluorescence, limits the sensitivity of the probe to low-micromolar levels of accumulated DAF-2 triazole (DAF-2 T), the activated form of the probe, which is higher than the concentrations of most endogenous nitrosation/nitrosylation products found in tissues. We further show that the compartmentalization of DAF-2 around elastic fibers further limits its potential to characterize the site of NO production at the subcellular level. Moreover, we find that reaction of DAF-2 with HgCl(2) and other commonly employed reagents is associated with spectral changes that may be misinterpreted as NO signals. Finally, UV illumination can lead to high levels of nitrosating species that interfere with NO detection from enzymatic sources. These findings indicate that while DAF-2 may still represent an important tool for the localization of NO synthesis, provided important pitfalls and limitations are taken into consideration, it is not suited for the detection of basally generated nitrosation/nitrosylation products.
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Affiliation(s)
- Juan Rodriguez
- Department of Molecular and Cellular Physiology, LSU Health Sciences Center, Shreveport, LA 71130, USA
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Kono T, Chisato N, Ebisawa Y, Asama T, Sugawara M, Ayabe T, Kohgo Y, Kasai S, Yoneda M, Takahashi T. Impaired nitric oxide production of the myenteric plexus in colitis detected by a new bioimaging system. J Surg Res 2004; 117:329-38. [PMID: 15047139 DOI: 10.1016/j.jss.2003.11.004] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2003] [Indexed: 02/01/2023]
Abstract
Direct measurement of the release of nitric oxide (NO) from the myenteric plexus has been extremely difficult to date, due to the lack of suitable methodologies. We have developed a new bioimaging system to visualize the nitrergic neurons of the myenteric plexus and investigated whether NO production is impaired in dextran sulfate sodium (DSS)-induced colitis. Longitudinal muscle layers with the myenteric plexus intact were obtained from the rat colon and were incubated with 4,5-diaminofluorescein-2-diacetate (DAF-2DA) (7 microm) for 30 min. Illumination at 450-490 nm revealed the fluorescence in the myenteric plexus. Confocal laser microscopy and three-dimensional reconstruction techniques were used to quantify the changes in the amount of NO production by the myenteric plexus. Fluorescent double-labeled immunostaining for nNOS was performed to confirm the colocalization of nNOS in 4,5-diaminofluorescein (DAF-2)-positive cells. DAF-2 fluorescence was abolished by pretreatment with N(G)-nitro-l-arginine methyl ester (l-NAME; a nonselective NOS inhibitor), 1-(2-trifluoromethylphenyl) imidazole (TRIM; a selective neuronal NOS inhibitor), and omega-conotoxin GVIA (an N-type Ca(2+) channel blocker), but not by nifedipine (an l-type Ca(2+) channel blocker). Fluorescent double-labeled immunostaining showed that DAF-2-positive cells colocalized with nNOS-positive cells. Oral administration of 5% DSS for 7 days induced distal colitis and the number of DAF-2-positive neurons were significantly reduced to 55 +/- 17% of control. DAF-2 offers a sensitive indicator for visualizing production of NO with high spatial resolution. This new system may contribute to the study of the pathophysiological role of the nitrergic pathway in the gastrointestinal tract.
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Affiliation(s)
- Toru Kono
- Department of Surgery II, Asahikawa Medical College, Asahikawa, Hokkaido 078-8510, Japan.
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