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Cerebrovascular recovery after stroke with individual and combined losartan and captopril treatment of SHRsp. Vascul Pharmacol 2017; 96-98:40-52. [DOI: 10.1016/j.vph.2017.08.004] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2017] [Revised: 07/28/2017] [Accepted: 08/17/2017] [Indexed: 11/23/2022]
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Michihara A, Oda A, Mido M. High Expression Levels of NADPH Oxidase 3 in the Cerebrum of Ten-Week-Old Stroke-Prone Spontaneously Hypertensive Rats. Biol Pharm Bull 2016; 39:252-8. [PMID: 26830484 DOI: 10.1248/bpb.b15-00663] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
We previously demonstrated that the high levels of oxidative stress in the brains of ten-week-old stroke-prone hypertensive rats (SHRSP) were attributable to intrinsic, not extrinsic factors (Biol. Pharm. Bull., 33, 2010, Michihara et al.). The aim of the present study was to determine whether increases in the enzymes producing reactive oxygen species (ROS), reductions in the enzymes and proteins removing ROS, or increases in an enzyme and transporter removing antioxidants promoted oxidative stress in the SHRSP cerebrum. No significant decreases were observed in the mRNA levels of enzymes that remove ROS between SHRSP and normotensive Wistar Kyoto rats. The activity of reduced nicotinamide adenine dinucleotide phosphate (NADPH) oxidase (NOX) and the protein and mRNA levels of NOX3, an enzyme that produces ROS, were significantly increased in the SHRSP cerebrum. These results suggested that the high expression levels of NOX3 increased oxidative stress in the SHRSP cerebrum.
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Affiliation(s)
- Akihiro Michihara
- Faculty of Pharmacy and Pharmaceutical Sciences, Fukuyama University
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Takemori K, Murakami T, Kometani T, Ito H. Possible involvement of oxidative stress as a causative factor in blood-brain barrier dysfunction in stroke-prone spontaneously hypertensive rats. Microvasc Res 2013; 90:169-72. [PMID: 23978333 DOI: 10.1016/j.mvr.2013.08.005] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2013] [Revised: 06/13/2013] [Accepted: 08/14/2013] [Indexed: 01/19/2023]
Abstract
To elucidate the pathogenic roles of oxidative stress on blood-brain-barrier (BBB) dysfunction, we compared the chronological changes of oxidative stress in blood and cerebral tissue between stroke-prone spontaneously hypertensive rats (SHRSP) and normotensive Wistar-Kyoto rats (WKY). Plasma and tissue oxidative stress was assayed by the diacron-reactive oxygen metabolite (d-ROM) test using 8-hydroxy-2'-deoxyguanosine (8-OHdG) as a reference oxidative stress marker. The plasma and cerebral cortex d-ROM levels increased in SHRSP after 16weeks of age, but not in WKY. There were no significant differences in 8-OHdG or lipid peroxidation markers between SHRSP and WKY. Antioxidant capacity, as estimated by the biological antioxidant potential test, was similar between SHRSP and WKY at all ages examined. The changes in plasma and tissue d-ROM levels coincided with changes in glucose transporter-1 and aquaporin-4 expression, as functional constituents of the BBB. These results indicate that plasma oxidative stress increases before the onset of tissue damage, and plays an important role in BBB dysfunction rather than decreases in antioxidant capacity. The plasma d-ROM test appears to be useful for predicting vasogenic cerebral edema in severe hypertension.
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Affiliation(s)
- Kumiko Takemori
- Department of Food Science and Nutrition, Faculty of Agriculture, Kinki University, Nara, Japan.
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Takemori K, Inoue T, Ito H. Possible role of nitric oxide generated by leukocytes in the pathogenesis of hypertensive cerebral edema in stroke-prone spontaneously hypertensive rats. Brain Res 2011; 1417:137-45. [DOI: 10.1016/j.brainres.2011.08.042] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2011] [Revised: 08/10/2011] [Accepted: 08/16/2011] [Indexed: 01/13/2023]
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Sousa T, Morato M, Fernandes E, Carvalho F, Albino-Teixeira A. Xanthine Oxidase Inhibition by 1,3-dipropyl-8-sulfophenyl-xanthine (DPSPX), an Antagonist of Adenosine Receptors. J Enzyme Inhib Med Chem 2008; 19:11-5. [PMID: 15202488 DOI: 10.1080/14756360310001634910] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Xanthine oxidase (XO), an enzyme involved in purine metabolism, is a source of either oxidants (superoxide radical) or antioxidants (uric acid). Interference with XO activity can lead to oxidative stress, thus contributing to the pathogenesis of cardiovascular diseases. The adenosine receptors antagonist, 1,3-dipropyl-8-sulfophenylxanthine (DPSPX), induces hypertension and cardiovascular injury in rats. Since DPSPX is a xanthine, we aimed at evaluating DPSPX's influence on XO activity to ascertain its contribution to DPSPX-induced hypertension. The activity of isolated XO in the presence of DPSPX was evaluated spectrophotometrically. Serum and urinary uric acid levels of DPSPX-treated rats were measured using a commercial kit. DPSPX inhibited XO activity in a concentration-dependent manner and reduced rat serum and urinary uric acid levels. It can be concluded that: DPSPX is an inhibitor of XO; decreased generation of uric acid may lead to oxidative stress, thus contributing to endothelial dysfunction and vascular morphological changes in DPSPX-treated rats.
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Affiliation(s)
- Teresa Sousa
- Institute of Pharmacology and Therapeutics, Faculty of Medicine of Porto, University of Porto, Alameda Prof. Hernâni Monteiro, 4200-319 Porto, Portugal
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Sui H, Wang W, Wang PH, Liu LS. Protective effect of antioxidant ebselen (PZ51) on the cerebral cortex of stroke-prone spontaneously hypertensive rats. Hypertens Res 2005; 28:249-54. [PMID: 16097369 DOI: 10.1291/hypres.28.249] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
An increase in reactive oxygen species has been shown to play a role in perpetuating hypertension and cerebral injury in stroke-prone spontaneously hypertensive rats (SHRsp). Lipid peroxidation in the cerebral cortex is much more intense in SHRsp after establishment of severe hypertension as compared to that in normotensive Wistar-Kyoto rats (WKY). Cortical neurons from SHRsp are more vulnerable to hypoxia and hyponutritional conditions. We sought to investigate whether long-term administration of seleno-glutathione peroxidase mimic ebselen (PZ51) would have a protective effect on cortical neurons in SHRsp, and, if so, the possible mechanisms of this effect. Twenty-two 8-week-old SHRsp were randomized into a PZ51 group and control group. Age-matched WKY were used as normal controls. We examined the levels of malonaldehyde (MDA) and nitric oxide (NO) in the cerebral cortex (CC) homogenate, detected the three isoforms of nitric oxide synthase (NOS) by Western blotting, and examined cortical neurons by transmission electron microscopy. The results showed that PZ51 treatment significantly decreased both MDA and NO in the CC, inhibited inducible nitric oxide synthase (iNOS) protein expression, and alleviated the damage to cortical neurons compared to the findings for the control group. In conclusion, the present study showed that PZ51 administration suppressed lipid peroxidation and inhibited iNOS protein expression in CC homogenate, and it was suggested that these mechanisms may play a role in the protective effects of PZ51 on cortical neurons of SHRsp.
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Affiliation(s)
- Hui Sui
- Cardiovascular Institute and Fuwai Hospital, Chinese Academy of Medical Sciences, Peking Union Medical College, No167 BeiLishi Road, Xicheng District, Beijing 100037, P.R. China.
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Kimura E, Fujimaki Y, Niwat M, Fujiwara M, Kadosaka T. Effects of Brugia pahangi infection on the cardiovascular system of stroke-prone spontaneously hypertensive rats. J Parasitol 2002; 88:839-42. [PMID: 12435117 DOI: 10.1645/0022-3395(2002)088[0839:eobpio]2.0.co;2] [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: 11/10/2022] Open
Abstract
To determine if filarial infection causes any effect on the cardiovascular system of the host animal, stroke-prone spontaneously hypertensive rats were infected with Brugia pahangi under the assumption that these rats would reveal pathological changes more clearly and in a shorter period than would ordinary rats. The infection resulted in loss of body weight, increase in heart weight, enlargement of left ventricle, and higher mortality rate.
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Affiliation(s)
- E Kimura
- Department of Parasitology, Aichi Medical University, Nagakute, Japan.
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Takemori K, Ito H, Suzuki T. Effects of inducible nitric oxide synthase inhibition on cerebral edema in severe hypertension. ACTA NEUROCHIRURGICA. SUPPLEMENT 2001; 76:335-8. [PMID: 11450038 DOI: 10.1007/978-3-7091-6346-7_69] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/20/2023]
Abstract
In order to clarify the causative role of cytotoxic nitric oxide (NO) in hypertensive cerebral injury, the effects of inducible nitric oxide synthase (iNOS) inhibition on leukocytes and endothelial function were examined using stroke-prone spontaneously hypertensive rats (SHRSP). For the iNOS inhibition, S-methylisothiourea (SMT) was administered to 12-week-old male SHRSP for 3 weeks. Immunohistochemical examination were carried out for the expression of intercellular adhesion molecule-1 (ICAM-1), glucose transporter-1 (GLUT-1), fibrinogen and glial fibrillary acidic protein (GFAP) in cerebral cortex. The effects of iNOS inhibition was also examined for Mac-1 expression by flow cytometric analysis. Plasma NO metabolites level was significantly lower in the SMT group than in the control group. Mac-1 expression was inhibited by SMT. In the SMT group, brain weight was significantly lower than in the control. By SMT administration, ICAM-1 expression was suppressed, GLUT-1 was enhanced, fibrinogen was decreased and GFAP was decreased as compared to those in control group. In hypertensive cerebral injury in SHRSP, iNOS-derived NO, mainly in activated leukocytes, could be an important causative factor for endothelial injury.
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Affiliation(s)
- K Takemori
- Department of Pathology, Kinki University School of Medicine, Osaka, Japan
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Ito H, Takemori K, Suzuki T. Role of angiotensin II type 1 receptor in the leucocytes and endothelial cells of brain microvessels in the pathogenesis of hypertensive cerebral injury. J Hypertens 2001; 19:591-7. [PMID: 11327634 DOI: 10.1097/00004872-200103001-00011] [Citation(s) in RCA: 56] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
OBJECTIVES To elucidate the mechanisms of activation of polymorphonuclear neutrophils (PMNs) and their adhesion to endothelial cells in hypertensive cerebral injury, and to determine the effects of angiotensin II type 1 (AT1) receptor antagonism on PMNs and endothelial cells. DESIGN We examined expression of AT1 receptor in PMNs in relation to that in endothelial cells of brain microvessels, using mature stroke-prone spontaneously hypertensive rats (SHRSP). METHODS To investigate the expression of AT1 receptor, we used 23-week-old male spSHRs and age-matched Wistar-Kyoto (WKY) rats. For the effects of AT1 receptor blockade, the AT1 receptor antagonist, TCV-116, was orally administered at a dosage of 0.5 mg/kg per day for 4 weeks in rats from age 19 weeks. A PMN-rich fraction was obtained by density gradient using Ficol-hypaque. AT1 receptor expression in PMNs was investigated by immunohistochemistry (avidin-biotinylated peroxidase complex method) and reverse transcriptase-polymerase chain reaction (RT-PCR). Expression of macrophage-1 (Mac-1) in PMNs was examined by flow cytometry. Expression of intercellular adhesion molecule-1, glucose transporter-1 and fibrinogen in the cerebral cortex (occipital region) was investigated by immunohistochemistry. RESULTS AT1 receptor was identified in PMNs by both immunohistochemistry and RT-PCR. It was also detected in the cerebral cortex. Expression in both types of cells was much more intense in spSHRs than in WKY rats. AT1 receptor antagonism ameliorated the enhanced expression of Mac-1 in PMNs. In addition, it was confirmed that enhanced expression of adhesion molecules and increased permeability of brain microvessels were decreased by AT1 receptor antagonism. CONCLUSIONS The results indicate that both PMNs and brain microvessel endothelial cells possess AT1 receptor, that AT1 receptor antagonism ameliorates endothelial injury via inhibition of PMNs and endothelial cell adhesion, and that angiotensin II must be a key factor in hypertensive endothelial injury.
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Affiliation(s)
- H Ito
- Department of Pathology, Kinki University School of Medicine, Osaka, Japan.
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Takemori K, Ito H, Suzuki T. Effects of the AT1 receptor antagonist on adhesion molecule expression in leukocytes and brain microvessels of stroke-prone spontaneously hypertensive rats. Am J Hypertens 2000; 13:1233-41. [PMID: 11078185 DOI: 10.1016/s0895-7061(00)01202-4] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
To elucidate the possible involvement of angiotensin II (AII) in the pathogenesis of microvascular changes in severe hypertension, we investigated the effects of angiotensin II type 1 (AT1) receptor antagonist and angiotensin-converting enzyme inhibitor (ACEI) on the expression of adhesion molecules of leukocytes and brain microvessels. Male stroke-prone spontaneously hypertensive rats (SHRSP) at 19 weeks of age were divided into three groups and age-matched Wistar-Kyoto rats (WKY) were used as the control group. AT1 receptor antagonist (TCV-116, 0.5 mg/kg/day) and ACEI (captopril, 20 mg/kg/day) were administered to SHRSP for 4 weeks. Mac-1 expression in leukocytes was investigated by flow cytometric analysis. For endothelial cells, we examined the expression of intercellular adhesion molecule-1 (ICAM-1), the AT1 receptor, and glucose transporter-1 (GLUT-1, a marker of the blood-brain barrier) using reverse transcription-polymerase chain reaction (RT-PCR). The blood pressure of AT1 receptor antagonist and ACEI-treated groups was slightly lower than that of the control, but was still greater than 220 mm Hg. Mac-1 expression, as well as ICAM-1 expression, was higher in control SHRSP than in WKY. Such enhanced expression of adhesion molecules in SHRSP was ameliorated by the administration of AT1 receptor antagonist or ACEI, the former being more effective. AT1 receptor expression was higher in control SHRSP than in WKY, and was lower in the AT1 receptor antagonist group, whereas no difference was found in the ACEI group. No significant differences were found in GLUT-1 expression among all groups. In the case of hypertensive cerebral injuries in SHRSP, leukocytes may have an important role for initiation via adhesion to endothelial cells. AT1 receptor antagonist showed a beneficial effect for the amelioration of enhanced expression of adhesion molecule in both leukocytes and endothelial cells. Thus, AII seems to be an important mediator for the hypertensive microvascular injuries.
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Affiliation(s)
- K Takemori
- Department of Pathology, Kinki University School of Medicine, Osaka, Japan
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Abstract
A change in endothelial function is a common phenomenon in patients with essential hypertension and in animals with hypertension, whether primary or induced by a salt-rich diet. In hypertensive subjects, there may be a change in the synthesis, or the effect, of nitric oxide. Nevertheless, hypertensive vasoconstriction is at present associated, above all, with the degradation of this mediator by free radicals, such as the superoxide anion, released in the dysfunctional vascular endothelium. These radicals are also formed when hypoxanthine is turned into xanthine, and when the latter becomes uric acid, both having been catalysed by the enzyme xanthine oxidase. In physiological conditions, the concentration of superoxide radicals remains low within the organism as a result of its reaction with the superoxide dismutase enzyme. However, in pathological situations, such as arterial hypertension, there may be an increase in the production of these radicals or a deficiency of the superoxide dismutase enzyme. In hypertensive patients, the release of vasoconstrictor peroxides derived from the activity of cyclo-oxygenase in the endothelium and the vascular smooth muscle is also important. The excess free radicals released by the dysfunctional endothelium also stimulate the synthesis of these contracting agents. Moreover, it should not be forgotten that endothelin-1, which is similarly synthesized and released in the vascular endothelium, is the most powerful known endogenous vasoconstrictor. This peptide would therefore play a prominent part in some forms of hypertension. Although no changes in endothelin plasma levels have been found in essential hypertension, there may be an increase in its local concentration. It should be borne in mind that endothelin could strengthen the effect of other vasoconstrictors. Moreover, it may also provoke the release of free radicals and of cyclo-oxygenase-derived vasoconstrictor factors. The latest theories therefore indicate that the increase in vasoconstriction, which characterizes arterial hypertension, is associated with a greater production of free radicals. At the present time, antioxidant agents and xanthine oxydase-inhibiting compounds are being used to treat hypertension and other pathologies linked to endothelial dysfunction. In addition, it is thought that the therapeutic benefit of some anti-hypertensive drugs, such as calcium antagonists and angiotensin-converting enzyme inhibitors, could be in part due to the inhibition of the production of free radicals that they provoke.
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Affiliation(s)
- A A De Artinano
- Departamento de Farmacologia, Facultad de Medicina, Universidad Complutense de Madrid, Ciudad Universitaria s/n., Madrid, 28040, Spain
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