Effects of chronic inhibition of inducible nitric oxide synthase in hyperthyroid rats

2005 ◽  
Vol 288 (6) ◽  
pp. E1252-E1257 ◽  
Author(s):  
Isabel Rodríguez-Gómez ◽  
Rosemary Wangensteen ◽  
Juan Manuel Moreno ◽  
Virginia Chamorro ◽  
Antonio Osuna ◽  
...  

We hypothesized that nitric oxide generated by inducible nitric oxide synthase (iNOS) may contribute to the homeostatic role of this agent in hyperthyroidism and may, therefore, participate in long-term control of blood pressure (BP). The effects of chronic iNOS inhibition by oral aminoguanidine (AG) administration on BP and morphological and renal variables in hyperthyroid rats were analyzed. The following four groups ( n = 8 each) of male Wistar rats were used: control group and groups treated with AG (50 mg·kg−1·day−1, via drinking water), thyroxine (T4, 50 μg·rat−1·day−1), or AG + T4. All treatments were maintained for 3 wk. Tail systolic BP and heart rate (HR) were recorded weekly. Finally, we measured BP (mmHg) and HR in conscious rats and morphological, plasma, and renal variables. T4 administration produced a small BP (125 ± 2, P < 0.05) increase vs. control (115 ± 2) rats. AG administration to normal rats did not modify BP (109 ± 3) or any other hemodynamic variable. However, coadministration of T4 and AG produced a marked increase in BP (140 ± 3, P < 0.01 vs. T4). Pulse pressure and HR were increased in both T4- and T4 + AG -treated groups without differences between them. Plasma NOx (μmol/l) were increased in the T4 group (10.02 ± 0.15, P < 0.05 vs. controls 6.1 ± 0.10), and AG reduced this variable in T4-treated rats (6.81 ± 0.14, P < 0.05 vs. T4) but not in normal rats (5.78 ± 0.20). Renal and ventricular hypertrophy and proteinuria of hyperthyroid rats were unaffected by AG treatment. In conclusion, the results of the present paper indicate that iNOS activity may counterbalance the prohypertensive effects of T4.

2020 ◽  
Vol 19 (30) ◽  
pp. 2795-2804 ◽  
Author(s):  
Ricardo Pereira Rodrigues ◽  
Juliana Santa Ardisson ◽  
Rita de Cássia Ribeiro Gonçalves ◽  
Tiago Branquinho Oliveira ◽  
Vinicius Barreto da Silva ◽  
...  

Background: Helicobacter pylori is a gram-negative bacterium related to chronic gastritis, peptic ulcer and gastric carcinoma. During its infection process, promotes excessive inflammatory response, increasing the release of reactive species and inducing the production of pro-inflammatory mediators. Inducible Nitric Oxide Synthase (iNOS) plays a crucial role in the gastric carcinogenesis process and a key mediator of inflammation and host defense systems, which is expressed in macrophages induced by inflammatory stimuli. In chronic diseases such as Helicobacter pylori infections, the overproduction of NO due to the prolonged induction of iNOS is of major concern. Objective: In this sense, the search for potential iNOS inhibitors is a valuable strategy in the overall process of Helicobacter pylori pathogeny. Method: In silico techniques were applied in the search of interesting compounds against Inducible Nitric Oxide Synthase enzyme in a chemical space of natural products and derivatives from the Analyticon Discovery databases. Results: The five compounds with the best iNOS inhibition profile were selected for activity and toxicity predictions. Compound 9 (CAS 88198-99-6) displayed significant potential for iNOS inhibition, forming hydrogen bonds with residues from the active site and an ionic interaction with heme. This compound also displayed good bioavailability and absence of toxicity/or from its probable metabolites. Conclusion: The top-ranked compounds from the virtual screening workflow show promising results regarding the iNOS inhibition profile. The results evidenced the importance of the ionic bonding during docking selection, playing a crucial role in binding and positioning during ligand-target selection for iNOS.


2016 ◽  
Vol 41 (3) ◽  
Author(s):  
Ayşe Nalbantsoy ◽  
Mert Karış ◽  
Leyla Karakaya ◽  
Yurdanur Akgül

AbstractObjective: The aim of this study is to investigate the in vitro cytotoxicity and iNOS (inducible nitric oxide synthase) inhibitory, and antioxidant activity in order to assess the traditional usage of Liquidambar orientalis Mill resin extract.Methods: Different solvent extracts of Liquidambar orientalis Mill resin were prepared. The cytotoxicity of extracts was determined using MTT (3-(4,5-dimethyl-2-thiazolyl)- 2,5-diphenyl-2H-tetrazoliumbromide) assay. HeLa (Human cervix adenocarcinoma), A-549 (Human alveolar adenocarcinoma), MCF-7 (Human breast adenocarcinoma), CaCo-2 (Human colon colorectal adenocarcinoma), mPANC96 (Human pancreas adenocarcinoma), PC-3 (Human prostate adenocarcinoma), U87MG (Human glioblastoma- astrocytoma) and as a normal cell line HEK293 (Human embryonic kidney cells) and Vero (African green monkey kidney epithelial cells) were used for testing cytotoxicity. RAW 264.7 (murine macrophage cell lines) was used to determine the inhibition levels of inducible nitric oxide synthase (iNOS). HL-60 (human acute myeloid leukemia) was used to determine antioxidant activity as DCF production per cent.Results: Hexane, dichloromethane, methanol and water extracts were prepared, and their iNOS inhibitory, cytotoxic and antioxidant activity were investigated. The estimated IC50 values of extracts varied from 6.68 to 48.90 μg/ ml after treatment with different doses of extracts for 48 h. Inhibition of the hexane, dichloromethane, methanol, and water extracts on LPS-induced NO production in RAW 264.7 macrophage were showed that the all extracts inhibited NO production in activated RAW 264.7 cells, except methanol extract. Hexane, dichloromethane and methanol extracts inhibited NO production with ICConclusion: This study is the first report showing the potential of Liquidambar orientalis Mill resin extracts for cytotoxicity, iNOS inhibition and the antioxidant activity as an alternative therapeutic approach for traditional uses. The results demonstrated that Liquidambar orientalis dichloromethane resin extracts showed strongest cytotoxic effect while all extracts except methanolic extracts exhibited moderate iNOS inhibition. All extracts other than hexane have a potent antioxidant effect in the cellular-based assay. In conclusion, further studies should focus on the purification of the active components of this extracts and to investigate the possible mode of action to obtain a better understanding of their potential use as cytotoxic, anti-inflammatory and antioxidant agents.


2013 ◽  
Vol 16 (3) ◽  
pp. 443-451 ◽  
Author(s):  
W. Barański ◽  
J. Kaleczyc ◽  
S. Zduńczyk ◽  
W. Podlasz ◽  
E. Długołęcka-Malinowska ◽  
...  

Abstract The expression of CD14+ macrophages, CD4+, CD8+ lymphocytes and mRNA of inducible nitric oxide synthase (iNOS) was investigated in the endometrium of repeat breeders with subclinical endometritis [experimental group (EXP), n = 10] and healthy [control group (CTRL), n = 10] cows. The cows were selected on the basis of repeat breeding (3 unsuccessful inseminations), clinical and cytological examinations (> 10% polymorphonuclear neutrophils in uterine smears obtained by cytobrush). From all the cows endometrial biopsies were collected and the presence of CD14+, CD4+ and CD8+ cells in the endometrium was evaluated immunohistochemically using semi quantitative counting method. The mRNA expression of iNOS was determined using reverse transcription-PCR. In general, there were no significant differences between EXP and CTRL groups in the expression of CD4+ and CD8 + lymphocytes in all endometrial structures. In contrast, we observed a higher number of CD14+ macrophages in repeat breeding group compared to the control cows, however, this difference was slightly pronounced. CD14+ cells were detectable only in the stratum compactum and stratum spongiosum. The statistically significant (p ≤ 0.05) higher expression of iNOS mRNA was measured in the cows with subclinical endometritis compared to the healthy animals. Our results suggest that the increased expression of CD14+ macrophages and iNOS mRNA may be associated with embryonal mortality in repeat breeding cows with subclinical endometritis.


2010 ◽  
Vol 24 (7) ◽  
pp. 1413-1422 ◽  
Author(s):  
Min Lu ◽  
PingPing Li ◽  
Jan Pferdekamper ◽  
WuQiang Fan ◽  
Maziyar Saberi ◽  
...  

Abstract Recent findings denote an important contribution of macrophage inflammatory pathways in causing obesity-related insulin resistance. Inducible nitric oxide synthase (iNOS) is activated in proinflammatory macrophages and modestly elevated in insulin-responsive tissues. Although the benefits of systemic iNOS inhibition in insulin-resistant models have been demonstrated, the role of macrophage iNOS in metabolic disorders is not clear. In the current work, we used bone marrow transplantation (BMT) to generate mice with myeloid iNOS deficiency [iNOS BMT knockout (KO)]. Interestingly, disruption of iNOS in myeloid cells did not protect mice from high-fat diet-induced obesity and insulin resistance. When mice were treated with the iNOS inhibitor, N6-(1-Iminoethyl)-L-lysine hydrochloride (L-NIL), we observed a significant and comparable improvement of glucose homeostasis and insulin sensitivity in both wild-type and iNOS BMT KO mice. We further demonstrated that absence of iNOS in primary macrophages did not affect acute TLR4 signaling pathways and had only a modest and mixed effect on inflammatory gene expression. With respect to TNFα treatment, iNOS KO macrophages showed, if anything, a greater inflammatory response. In summary, we conclude that iNOS inhibition in tissues other than myeloid cells is responsible for the beneficial effects in obesity/insulin resistance.


Shock ◽  
2000 ◽  
Vol 13 (4) ◽  
pp. 261-266 ◽  
Author(s):  
Kazutaka Soejima ◽  
Roy McGuire ◽  
Ned Snyder ◽  
Tatsuo Uchida ◽  
Csaba Szabó ◽  
...  

2007 ◽  
Vol 107 (6) ◽  
pp. 963-970 ◽  
Author(s):  
Ping Zhao ◽  
Longyun Peng ◽  
Liaoliao Li ◽  
Xuebing Xu ◽  
Zhiyi Zuo

Background Preconditioning the brain with relatively safe drugs seems to be a viable option to reduce ischemic brain injury. The authors and others have shown that the volatile anesthetic isoflurane can precondition the brain against ischemia. Here, the authors determine whether isoflurane preconditioning improves long-term neurologic outcome after brain ischemia. Methods Six-day-old rats were exposed to 1.5% isoflurane for 30 min at 24 h before the brain hypoxia-ischemia that was induced by left common carotid arterial ligation and then exposure to 8% oxygen for 2 h. The neuropathology, motor coordination, and learning and memory functions were assayed 1 month after the brain ischemia. Western analysis was performed to quantify the expression of the heat shock protein 70, Bcl-2, and survivin 24 h after isoflurane exposure. Results The mortality was 45% after brain hypoxia-ischemia. Isoflurane preconditioning did not affect this mortality. However, isoflurane preconditioning attenuated ischemia-induced loss of neurons and brain tissues, such as cerebral cortex and hippocampus in the survivors. Isoflurane also improved the motor coordination of rats at 1 month after ischemia. The learning and memory functions as measured by performance of Y-maze and social recognition tasks in the survivors were not affected by the brain hypoxia-ischemia or isoflurane preconditioning. The expression of Bcl-2, a well-known antiapoptotic protein, in the hippocampus is increased after isoflurane exposure. This increase was reduced by the inhibitors of inducible nitric oxide synthase. Inducible nitric oxide synthase inhibition also abolished isoflurane preconditioning-induced neuroprotection. Conclusions Isoflurane preconditioning improved the long-term neurologic outcome after brain ischemia. Inducible nitric oxide synthase may be involved in this neuroprotection.


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