To study the expression of angiotensin converting enzyme 2 (ACE2) and angiotensin (Ang) 1-7 specific receptor Mas protain in renal blood vessels of metabolic syndrome ( MS) rats and its anti-oxidative effect. A total of 80 male SD rats were divided into four groups: the normal control group (NC, the same volume of normal saline), the MS group (high fat diet), the MS + Astragali Radix group (MS + HQ, 6 g x kg(-1) x d(-1) in gavage) and the MS + Valsartan group (MS + XST, 30 mg x kg(-1) x d(-1) in gavage). After four weeks of intervention, their general indexes, biochemical indexes and blood pressure were measured; plasma and renal tissue Ang II, malondialdehyde (MDA) and superoxide demutase (SOD) levels were measured with radioimmunoassay. The protein expressions of Mas receptor, AT1R, ACE and ACE2 were detected by western blot analysis. According to the result, compared with the NC group, the MS group and the MS + HQ group showed significant increases in systolic and diastolic pressures, body weight, fasting glucose, fasting insulin, triglycerides, free fatty acid and Ang II level of MS rats (P < 0.05). The MS + XST group showed notable decreases in systolic and diastolic pressures than that of the MS group. The MS group showed significant increases in the SOD activity and NO level and decrease in the MDA level after being intervened with Astragali Radix. ACE and AT1R protein expressions in renal tissues of the MS group were higher than that in the NC group, but with lower ACE2 and -Mas receptor expressions (all P < 0.05). Compared with the MS group, the MS + HQ group showed significant increase in Mas receptor expression in renal tissues, whereas the MS + XST group showed notable decrease in AT1R (all P < 0.05). In conclusion, Astragali Radix can increase the Mas receptor expressions in renal tissues, decrease ACE expression and change local Ang II, MDA, NO and SOD in kidneys, so as to protect early damages in renal tissues.
Angiotensin I ; metabolism ; Animals ; Astragalus Plant ; chemistry ; Blood Glucose ; metabolism ; Blood Pressure ; drug effects ; Drugs, Chinese Herbal ; administration & dosage ; Humans ; Kidney ; drug effects ; injuries ; metabolism ; Male ; Malondialdehyde ; metabolism ; Metabolic Syndrome ; drug therapy ; genetics ; metabolism ; physiopathology ; Peptide Fragments ; metabolism ; Peptidyl-Dipeptidase A ; genetics ; metabolism ; Proto-Oncogene Proteins ; genetics ; metabolism ; Rats ; Rats, Sprague-Dawley ; Receptors, G-Protein-Coupled ; genetics ; metabolism ; Signal Transduction ; drug effects

OBJECTIVETo elucidate the effect of valsartan on human glomerular mesangial cells oxidative stress and the expression of the receptor for advanced glycation end products (RAGE) induced by the advanced glycation end-products (AGEs).

METHODSHuman glomerular mesangial cells were treated with advanced glycation end-product-bovine serum albumin (AGE-BSA) in the presence of valsartan. The reactive oxygen species (ROS) in cells were measured by Flow cytometry, and the mRNA of p47 phox, which was the primary subunits of NADPH oxidase, was detected by semi-quantitative reberse transcription polymerase chain reaction (RT-PCR). The mRNA of RAGE was detected by RT-PCR and the RAGE protein was assayed by immunocytochemistry.

RESULTSThe product of ROS, and the expression of p47 phox and RAGE in mesangial cells, which were treated with AGE-BSA in the presence of valsartan, were down-regulated compared with the groups treated with AGE-BSA (P < 0.05). Valsartan dose-dependently and time-dependently inhibited the AGE-elicited overexpression of RAGE, ROS and p47(phox) in mesangial cells.

CONCLUSIONValsartan could inhibit RAGE expression through downregulation of oxidative stress.

Angiotensin II Type 1 Receptor Blockers ; pharmacology ; Antioxidants ; pharmacology ; Glycation End Products, Advanced ; pharmacology ; Humans ; Mesangial Cells ; cytology ; metabolism ; Oxidative Stress ; drug effects ; RNA, Messenger ; genetics ; metabolism ; Receptor for Advanced Glycation End Products ; Receptors, Immunologic ; genetics ; metabolism ; Serum Albumin, Bovine ; pharmacology ; Tetrazoles ; pharmacology ; Valine ; analogs & derivatives ; pharmacology ; Valsartan

Animals ; Hypertension ; metabolism ; physiopathology ; Male ; Myocardium ; metabolism ; Peptidyl-Dipeptidase A ; genetics ; metabolism ; Proto-Oncogene Proteins ; genetics ; metabolism ; RNA, Messenger ; genetics ; metabolism ; Rats ; Rats, Inbred SHR ; Rats, Inbred WKY ; Receptor, Angiotensin, Type 1 ; genetics ; metabolism ; Receptors, G-Protein-Coupled ; genetics ; metabolism

OBJECTIVEThis study was undertaken to observe the change in the local level of angiotensin II (Ang II) and the expression of its corresponding receptors AT1 and AT2 during wound healing, and explore the possible role of Ang II in wound healing .

METHODSA model of full-thickness cutaneous wound was developed on the back of C57/BL6 mice. Specimens were taken from the wound of each mouse on the day 0, 1, 3, 5, 7, 9, 11, 13 and 15 after wounding. The change in the generation of Ang II in wounded tissue during the healing process was detected with ELISA. The proliferation and the apoptosis of cells were detected by bromodeoxyuridine (Brdu) and terminal deoxynucleotidyl transferase mediated deoxyuridine triphosphate nick end labeling (TUNEL) method in wounded skin during the healing process, respectively. The cellular localization and the mRNA level change of Ang II receptors in wounded tissue during healing were detected with immunostaining and RT-PCR.

RESULTSAng II produced in wounded skin was increased in the first 7 days to reach the peak, and then gradually decreased during wound healing. BrdU labeling index was increased gradually in the first 7 days to reach the peak, and then gradually decreased during wound healing. The number of TUNEL-positive cells was increased slowly in the first 7 days after wounding. The increase in the number of TUNEL-positive cells was more markedly after epithelization of the wound. In normal mice, AT1 and AT2 receptor were found positively expressed in the whole epidermal layer, while positive expression was only found in the endothelial cells of the capillary vessels within the dermal layer, and positive expression was also found in appendages of the skin, i. e. hair follicle, sweat gland and sebaceous gland respectively. Positive staining signal of both AT1 and AT2 receptors were increased in the first 7 days to reach the peak, then gradually decreased. Expression of AT2R was increased again following the epithelization of wound. The result of RT-PCR showed that the expression of both AT1 and AT2 receptors was detectable, and AT1 receptor was increased in the first 7 days to the peak, and then gradually decreased during wound healing, while AT2 receptor expression reached its peak value on day 7, then gradually decreased, and increased again following the epithelization of wound.

CONCLUSIONSThese results indicate that Ang II participate in wound repair and related to remolding in the late stage of wound healing through the change in production of angiotensin II and expression of AT1 and AT2 receptors. AT1 receptor might be closely associated with cell proliferation, while AT2 receptor might play a role in cell apoptosis and remolding during wound healing.

Angiotensin II ; genetics ; metabolism ; Animals ; Apoptosis ; Cell Proliferation ; Male ; Mice ; Mice, Inbred C57BL ; RNA, Messenger ; genetics ; Receptors, Angiotensin ; genetics ; metabolism ; Skin ; injuries ; metabolism ; pathology ; Wound Healing ; physiology

Angiotensin II is a major effector molecule in the development of cardiovascular disease. In vascular smooth muscle cells (VSMCs), angiotensin II promotes cellular proliferation and extracellular matrix accumulation through the upregulation of plasminogen activator inhibitor-1 (PAI-1) expression. Previously, we demonstrated that small heterodimer partner (SHP) represses PAI-1 expression in the liver through the inhibition of TGF-beta signaling pathways. Here, we investigated whether SHP inhibited angiotensin II-stimulated PAI-1 expression in VSMCs. Adenovirus-mediated overexpression of SHP (Ad-SHP) in VSMCs inhibited angiotensin II- and TGF-beta-stimulated PAI-1 expression. Ad-SHP also inhibited angiotensin II-, TGF-beta- and Smad3-stimulated PAI-1 promoter activity, and angiotensin II-stimulated AP-1 activity. The level of PAI-1 expression was significantly higher in VSMCs of SHP-/- mice than wild type mice. Moreover, loss of SHP increased PAI-1 mRNA expression after angiotensin II treatment. These results suggest that SHP inhibits PAI-1 expression in VSMCs through the suppression of TGF-beta/Smad3 and AP-1 activity. Thus, agents that target the induction of SHP expression in VSMCs might help prevent the development and progression of atherosclerosis.
Adenoviridae/genetics ; Angiotensin II/*pharmacology ; Animals ; Blotting, Northern ; Cells, Cultured ; Electrophoretic Mobility Shift Assay ; Genetic Vectors/genetics ; Humans ; Mice ; Muscle, Smooth, Vascular/*cytology ; Myocytes, Smooth Muscle/*drug effects/*metabolism ; Plasminogen Activator Inhibitor 1/*genetics ; Promoter Regions, Genetic/genetics ; Rats ; Receptors, Cytoplasmic and Nuclear/genetics/*metabolism ; Reverse Transcriptase Polymerase Chain Reaction ; Smad3 Protein/genetics ; Transforming Growth Factor beta/pharmacology

OBJECTIVETo investigate the effect of irbesartan on the renal expressions of advanced glycation end products (AGEs) and their receptor (RAGEs) in rats with early diabetic nephropathy (DN) and the renoprotection mechanism of irbesartan.

METHODSRat DN models established by a single injection of streptozotocin were randomly divided into the model group and irbesartan treatment group. With normal rats as the control, all the rats received daily gavage for 8 weeks. The 24-h urinary protein excretion and contents of AGEs in the serum and kidney tissues were measured. The expressions of RAGEs and RAGEs protein and mRNA in the kidney tissues were detected by immunohistochemistry and reverse transcription-polymerase chain reaction, respectively. The pathological changes of the kidney were also assessed microscopically.

RESULTSIrbesartan significantly reduced the 24-h urinary protein excretion and the contents of AGEs in the serum and kidney tissues of DN rats, resulting also in decreased expressions of RAGEs and RAGEs protein and mRNA levels in the kidney. The treatment obviously alleviated the pathological changes in the kidney of the DN rats.

CONCLUSIONIrbesartan offers renoprotection against DN possibly by reducing the serum and renal contents of AGEs and inhibiting the renal mRNA expressions of RAGEs and RAGEs.

Angiotensin II Type 1 Receptor Blockers ; therapeutic use ; Animals ; Biphenyl Compounds ; therapeutic use ; Diabetes Mellitus, Experimental ; complications ; Diabetic Nephropathies ; drug therapy ; metabolism ; Glycation End Products, Advanced ; genetics ; metabolism ; Kidney ; metabolism ; Male ; RNA, Messenger ; genetics ; metabolism ; Random Allocation ; Rats ; Rats, Sprague-Dawley ; Receptor for Advanced Glycation End Products ; Receptors, Immunologic ; genetics ; metabolism ; Tetrazoles ; therapeutic use

OBJECTIVETo investigate the effect of losartan on cardiac mineralocorticoid receptor (MR) mRNA in rats after acute myocardial infarction (AMI).

METHODAMI was induced in male SD rats by ligation of the left coronary artery. The survived rats were randomly divided into AMI group, losartan group, and sham-operated group. The cardiac functions of the rats were assessed by echocardiogram and hemodynamics, and the contents of angiotensin II (Ang II) and aldosterone (Ald) in the myocardial tissues were determined by radioimmunoassay. The collagen density in the myocardial tissues were calculated by Masson's trichrome staining and the expression of MR mRNA were determined by real-time quantitative fluorescent PCR.

RESULTSBoth the contents of AngII and Ald in the myocardial tissues increased significantly in AMI group compared with those in the sham-operated group (P<0.01). The expression of MR mRNA and collagen density in the myocardial tissues also increased significantly than that in sham-operated group (P<0.01). After four weeks of losartan treatment, the contents of AngII and Ald in the myocardial tissues decreased significantly (P<0.05) and the expression of MR mRNA was also considerably lowered (P<0.01) in comparison with those in the AMI group. Treatment with losartan also resulted in significant decrease of the collagen density in the myocardial tissues.

CONCLUSIONSLosartan may reduce reactive fibrosis not only by attenuating the Ald signaling pathway but also by decreasing the expression of MR.

Aldosterone ; metabolism ; Angiotensin II ; metabolism ; Angiotensin II Type 1 Receptor Blockers ; therapeutic use ; Animals ; Fibrosis ; etiology ; prevention & control ; Losartan ; therapeutic use ; Male ; Myocardial Infarction ; drug therapy ; metabolism ; Myocardium ; pathology ; RNA, Messenger ; genetics ; metabolism ; Random Allocation ; Rats ; Rats, Sprague-Dawley ; Receptors, Mineralocorticoid ; genetics ; metabolism

BACKGROUNDMany studies have suggested that angiotensin II (Ang II) and its receptors may be involved in the development of asthma. However, the expression of angiotensin II receptors (AGTR) is not clear in the lung tissue of chronic asthmatics. This study was designed to determine the relationship between airway remodeling, dysfunction and the expression of AGTRs in a rat model of asthma.

METHODSRats were sensitized with ovalbumin (OVA) for 2 weeks. Sixty minutes before an inhalation challenge, the rats were pretreated either with valsartan (15, 30, 50 mg x kg(-1) x d(-1)) or saline intragastrically. Then the rats received an OVA challenge for 30 alternative days. Acetylcholine (Ach)-induced bronchoconstriction was measured after the final antigen challenge. White cell counts in bronchoalveolar lavage fluid (BALF) and morphological changes in the airways were then assessed. The levels of transforming growth factor-beta 1 (TGF-beta(1)) and platelet-derived growth factor (PDGF) in BALF were detected by ELISA. The levels of AGTR1 and AGTR2 mRNA and protein in lung tissues were measured by RT-PCR and Western blotting.

RESULTSAGTR1 mRNA and protein levels in repeatedly OVA-challenged rats were significantly increased as compared with negative controls. The AGTR1 mRNA expression versus white cell counts of BALF and airway wall thickness (mainly in small airways) in lungs of chronic antigen-exposed rats were positively correlated. Valsartan decreased the level of AGTR1 in repeatedly OVA-challenged rats. However, AGTR2 mRNA and protein levels in the OVA-challenged rats and high-dose valsartan-treated rats (50 mg x kg(-1) x d(-1)) were also increased. Valsartan significantly decreased inflammatory cell accumulation and attenuated Ach-evoked bronchoconstriction in repeatedly antigen-challenged rats. Valsartan also decreased allergen-induced structural changes in rat airway (including total airway wall thickness and smooth muscle area) and the levels of TGF-beta(1) and PDGF in BALF.

CONCLUSIONSAGTR1 expression is potentially associated with airway remodeling and dysfunction in asthma. Ang II and AGTR1 may participate in airway inflammation and airway remodeling of chronic antigen-exposed rats. Valsartan, a AGTR1 antagonist, could inhibit AGTR1 expression and partially inhibits structural airway changes as well as airway inflammation in chronic OVA-exposed rats.

Angiotensin II Type 1 Receptor Blockers ; pharmacology ; Angiotensin Receptor Antagonists ; Animals ; Asthma ; chemically induced ; genetics ; metabolism ; Blotting, Western ; Bronchoalveolar Lavage Fluid ; chemistry ; Enzyme-Linked Immunosorbent Assay ; Gene Expression ; drug effects ; Lung ; drug effects ; metabolism ; pathology ; Male ; Ovalbumin ; Platelet-Derived Growth Factor ; metabolism ; Rats ; Rats, Wistar ; Receptor, Angiotensin, Type 1 ; genetics ; metabolism ; Receptor, Angiotensin, Type 2 ; genetics ; metabolism ; Receptors, Angiotensin ; genetics ; metabolism ; Reverse Transcriptase Polymerase Chain Reaction ; Tetrazoles ; pharmacology ; Transforming Growth Factor beta1 ; metabolism ; Valine ; analogs & derivatives ; pharmacology ; Valsartan

OBJECTIVETo investigate the mechanism of a novel angiotensin II type 1 receptor-associated protein (ATRAP) interfering with angiotensin II type 1 (AT1) receptor-mediated vascular smooth muscle cell (VSMC) growth and neointimal formation.

METHODSVSMCs isolated from thoracic aorta of adult Sprague-Dawley (SD) rats were used in this study. ATRAP cDNA was subcloned into pcDNA3 vector and then transfected into VSMCs. DNA synthesis and extracellular signal-regulated kinase (ERK) and phospho-ERK expressions in VSMCs were assayed by measurement of 3H thymidine incorporation and Western blotting, respectively. Morphological changes were observed in the balloon injured artery with or without transfection of ATRAP cDNA using 12-week-old male SD rats.

RESULTSATRAP overexpression in VSMCs inhibited angiotensin II (Ang II)-induced 3H thymidine incorporation 48 hours after Ang II stimulation (P < 0.05). In VSMC, Ang II stimulation increased the phosphorylation of ERK, which reached the peak around 60 minutes. The activation of phospho-ERK was significantly decreased by ATRAP (P < 0.05). Neointimal formation was markedly inhibited by ATRAP overexpression in injuried arteries.

CONCLUSIONSThe AT1 receptor-derived activation of ERK plays an essential role in Ang II-induced VSMC growth. The growth inhibitory effects of ATRAP might be due to interfering with AT1 receptor-mediated activation of ERK in VSMC growth and neointimal formation.

Angiotensin II ; pharmacology ; Animals ; Aorta, Thoracic ; cytology ; Cell Division ; Extracellular Signal-Regulated MAP Kinases ; metabolism ; Male ; Muscle, Smooth, Vascular ; cytology ; physiology ; Phosphorylation ; Rats ; Rats, Sprague-Dawley ; Receptor, Angiotensin, Type 1 ; physiology ; Receptors, Angiotensin ; genetics ; physiology ; Transfection ; Tunica Intima ; cytology

OBJECTIVETo investigate the effect of alpha-zearalenol on angiotensin II-induced beta3 integrin mRNA expression in human umbilical vein endothelial cells (HUVECs).

METHODSThe mRNA level in integrin beta3 was determined by reverse transcription-polymerase chain reaction. Endothelial NF-kappaB activity was determined by the luciferase activity assay of plasmid NF-kappaB-LUC.

RESULTSThe angiotensin II-induced beta3 integrin mRNA expression was inhibited by alpha-zearalenol and 17beta-estradiol (10 nmol/L -1 micromol/L), but not influenced by ICI 182, 780, a pure competitive antagonist for estrogen receptor or a nitric oxide inhibitor Nomega-Nitro-L-arginine methyl ester hydrochloride. Alpha-zearalenol and 17beta-estradiol suppressed the angiotensin II-induced activation of NF-kappaB in endothelial cells.

CONCLUSIONAlpha-zearalenol inhibits angiotensin II-induced integrin beta3 mRNA expression by suppressing NF-kappaB activation in endothelial cells.

Angiotensin II ; antagonists & inhibitors ; Cells, Cultured ; Endothelial Cells ; drug effects ; metabolism ; Endothelium, Vascular ; drug effects ; metabolism ; Estradiol ; pharmacology ; Female ; Gene Expression Regulation ; Humans ; Integrin beta3 ; biosynthesis ; genetics ; NF-kappa B ; antagonists & inhibitors ; physiology ; Nitric Oxide ; antagonists & inhibitors ; Phytoestrogens ; pharmacology ; RNA, Messenger ; metabolism ; Receptors, Estrogen ; antagonists & inhibitors ; Zeranol ; analogs & derivatives ; pharmacology