OBJECTIVETo observe the effect of electroacupuncture (EA) stimulation on the expressions of angiotensinogen (AGT), angiotensin II type 1 receptor (AT1R), endothelin-1 (ET1), and endothelin A receptor (ETAR) mRNA in spontaneously hypertensive rat (SHR) aorta.

METHODSEighteen male SHRs were randomly divided into three groups, an SHR group, an SHR Baihui (DU 20) and Zusanli (ST 36) acupoint (SHR-AP) group, and an SHR non-acupoint (SHR-NAP) group, with 6 rats in each group. Six Wistar rats were used as a control. Rats in the SHR-AP group were stimulated by DU 20 and ST 36 acupoints, both of which were connected with EA. EA was handled one time every Monday, Wednesday and Friday, for total 24 times (8 weeks). SHRNAP rats were acupointed at a 15°angle flat into 0.5 cm to two points, which were 1 and 2 cm from rail tip separately. EA parameters were the same as the SHR-AP rats. SHR control rats and Wistar rats were fixed without EA. Real-time quantitative polymerase chain reaction (PCR) was used to measure AGT, AT1R, ET1, and ETAR mRNA expression in rat aorta.

RESULTSEA stimulation significantly reduced rat aorta vascular AGT, ET1, ETAR and AT1R mRNA expressions in the SHR-AP and SHR-NAP groups (P <0.01). Among these four genes, AT1R mRNA expression was significantly lower in the SHR-AP than in the SHR-NAP group (P <0.01).

CONCLUSIONEA could reduce the AT1R mRNA expression in SHR-AP rat aorta, indicating a potential mechanism for the hypotensive effects of EA.

Angiotensinogen ; genetics ; metabolism ; Animals ; Aorta ; metabolism ; physiopathology ; Blood Pressure ; Electroacupuncture ; Endothelin-1 ; genetics ; metabolism ; Gene Expression Regulation ; Male ; RNA, Messenger ; genetics ; metabolism ; Rats, Inbred SHR ; Receptor, Angiotensin, Type 1 ; genetics ; metabolism ; Receptor, Endothelin A ; genetics ; metabolism

OBJECTIVESTo investigate the protective effects of Sapindus saponins in spontaneously hypertensive rats, and the possible cellular and molecular mechanisms.

METHODSThirty-two 16-week-old spontaneously hypertensive rats were randomly divided into four groups (8 in each group): model group (placebo), positive control group (27 mg/kg of Captopril Tablets), Sapindus saponins groups (27 mg/kg and 108 mg/kg, respectively). Another 8 healthy Wistar-Kyoto strain (WKY) rats were used as the normal group. The animals were treated for 8 weeks. Blood pressure of rats was determined by non-invasive blood pressure meter (BP-6). Furthermore, the contents of angiotensin II (Ang II) in plasma and myocardial tissue were determined by enzyme-linked immunosorbent assay (ELISA), the gene expression of receptor angiotensin type 1 (AT1R) in aorta was determined by quantitative realtime polymerase chain reaction (qRT-PCR). The protein expression of transforming growth factor-β1 (TGF-β1) and AT1R in heart was determined by immunohistochemical staining. The protein expression of p-phosphorylation of p38 mitogen-activated protein kinase (p-p38MAPK) was determined by Western blotting. The contents of interleukin (IL)-1, IL-6 and tumor necrosis factor (TNF) in serum were determined by radioimmunoassay. And the histopathological and morphological changes of aorta and heart tissue samples were assessed semi-quantitatively by hematoxylin-eosin (HE) or Masson staining.

RESULTSThirty minutes after single or continuous treatment, systolic blood pressure (SBP) was reduced significantly in Sapindus saponins groups. And the contents of AngII, IL-1, IL-6 and TNF-α in serum, the expression of AT1R mRNA, p-p38MAPK and TGF-β1 were significantly suppressed dose-dependently (P<0.05 or P<0.01). With the Sapindus saponins treatment, compared with those of the model group, the cardiac and aortic pathological changes were ameliorated significantly.

CONCLUSIONSOur findings suggest that Sapindus saponins might have protective effects in spontaneously hypertensive rats, the cellular and molecular mechanisms of which might be relevant to the regulation of inflammatory responses mediated by p-p38MAPK signal pathway based on activated Ang II and AT1R.

Angiotensin II ; metabolism ; Animals ; Aorta ; drug effects ; pathology ; physiopathology ; Blood Pressure ; drug effects ; Collagen ; metabolism ; Female ; Hypertension ; blood ; drug therapy ; enzymology ; physiopathology ; Interleukin-1 ; blood ; Interleukin-6 ; blood ; Male ; Phosphorylation ; drug effects ; Protective Agents ; pharmacology ; therapeutic use ; Rats, Inbred SHR ; Receptor, Angiotensin, Type 1 ; metabolism ; Renin-Angiotensin System ; drug effects ; Sapindus ; chemistry ; Saponins ; pharmacology ; therapeutic use ; Transforming Growth Factor beta1 ; metabolism ; Tumor Necrosis Factor-alpha ; blood ; p38 Mitogen-Activated Protein Kinases ; metabolism

OBJECTIVETo investigate the effects of non-neuronal muscarinic receptors (NNMR) stimulation on atherosclerosis and endothelial cells activation.

METHODSAtherosclerosis model was established in ApoE-/- mice by a high fat diet for 7 weeks. During the experimental periods, animals were received a low (7 mg/kg/d) or a high (21 mg/kg/d) dose of arecoline by gavage. At the termination of the treatments, serum total cholesterol and NO levels were measured, and the aorta morphology was analyzed by hematoxylin and eosin staining. The gene expression of monocyte chemoattractant protein-1 (MCP-1) and adhesion molecules in the thoracic aortas was determined by RT-PCR, and the MCP-1 protein expression and NF-κB activity were detected by Western blot analysis. NO production, MCP-1 secretion in cultured rat aortic endothelial cells (RAECs), and monocyte-endothelium adhesion assay were also performed after arecoline treatments.

RESULTSArecoline efficiently decreased atherosclerotic plaque areas, increased serum nitric oxide (NO) content, suppressed the mRNA and protein expression of MCP-1, and modulated the IκB-α degradation and P65 phosphorylation in the aortae of ApoE-/- mice. Furthermore, arecoline promoted NO production and suppressed MCP-1 secretion in cultured RAECs after ox-LDL exposure, and either atropine or NG-nitro-L-arginine methylester could abrogate these effects. Arecoline also significantly inhibited the adherence of U937 monocytes to the ox-LDL injured human umbilical vein endothelial cells, which could be abolished by atropine.

CONCLUSIONOur results indicate that arecoline attenuates the progression of atherosclerosis and inhibits endothelial cells activation and adherence by stimulating endothelial NNMR. These effects, at least in part, are due to its modulation on NF-κB activity.

Animals ; Aorta ; cytology ; Apolipoproteins E ; Arecoline ; pharmacology ; Atherosclerosis ; physiopathology ; prevention & control ; Cell Adhesion Molecules ; metabolism ; Chemokine CCL2 ; metabolism ; Cholesterol ; blood ; Disease Progression ; Endothelial Cells ; cytology ; drug effects ; Endothelium, Vascular ; Human Umbilical Vein Endothelial Cells ; cytology ; Humans ; I-kappa B Proteins ; metabolism ; Lipoproteins, LDL ; Mice ; Mice, Knockout ; Monocytes ; cytology ; NF-KappaB Inhibitor alpha ; Nitric Oxide ; blood ; Nitroarginine ; pharmacology ; Rats ; Receptors, Muscarinic ; physiology ; Transcription Factor RelA ; metabolism

The aim of the present study is to investigate the effects of sequoyitol (Seq) on expression of eNOS and NOX4 in aortas of type 2 diabetic rats. Type 2 diabetic rats induced by high fat and high sugar diet and low dose of streptozotocin (STZ, 35 mg x kg(-1)) and were administered Seq (12.5, 25 and 50 mg x kg(-1) x d(-1)) for 6 weeks. The fasting blood glucose (FBG) and body weight were tested. Acetylcholine (Ach) induced endothelium-dependent relaxation and sodium nitroprusside (SNP) induced endothelium-independent relaxation were measured in aortas for estimating endothelial function. Aortic morphological change was observed with HE staining. The level of serum insulin was measured by radioimmunoassay. The total antioxidative capacity (T-AOC), malondialdehyde (MDA) and NO levels in aortas were determined according to the manufacturer's instructions. In addition, the expressions of eNOS and NOX4 in aortas were measured by immunohistochemisty, real-time PCR or Western blotting. The results showed that Seq significantly decreased FBG and insulin resistance, and improved aortic endothelium-dependent vasorelaxation function. The expressions of NOX4 and MDA content were obviously decreased, while the expression of eNOS, the levels of NO and T-AOC increased significantly in aortas of diabetic rats with Seq treatment. In conclusion, Seq protects against aortic endothelial dysfunction of type 2 diabetic rats through down-regulating expression of NOX4 and up-regulating eNOS expression.
Animals ; Aorta ; metabolism ; pathology ; Blood Glucose ; metabolism ; Body Weight ; Diabetes Mellitus, Experimental ; chemically induced ; metabolism ; physiopathology ; Diabetes Mellitus, Type 2 ; chemically induced ; metabolism ; physiopathology ; Hypoglycemic Agents ; pharmacology ; Inositol ; analogs & derivatives ; pharmacology ; Insulin ; blood ; Insulin Resistance ; Male ; Malondialdehyde ; metabolism ; NADPH Oxidase 4 ; NADPH Oxidases ; metabolism ; Nitric Oxide ; metabolism ; Nitric Oxide Synthase Type III ; metabolism ; Oxidation-Reduction ; drug effects ; Rats ; Rats, Sprague-Dawley ; Streptozocin ; Vasodilation ; drug effects

OBJECTIVETo observe the influence of high blood glucose fluctuation on the endothelial function of type 2 diabetes mellitus (T2DM) rats and the effects of Panax Quinquefolius Saponin (PQS) of stem and leaf.

METHODSThe T2DM model was induced by intraperitoneal injection of a small dose of streptozotocin (STZ, 35 mg/kg) plus high fat and high caloric laboratory chow. Then, diabetic rats were divided into steady high blood glucose (SHG) group and fluctuant high blood glucose (FHG) group according to fasting blood glucose coefficient of variation (FBG-CV), and then, the FHG group rats were divided into 4 groups according to the level of FBG-CV and fasting blood glucose: PQS 30 mg/(kg·d) group, PQS 60 mg/(kg·d) group, metformin hydrochloride control (MHC) group, and FHG control group, 10 in each group. Meanwhile, 10 rats without any treatment were used as normal control (NOR) group. Eight weeks later, the aortic arteries histology, plasma hepatocyte growth factor (HGF), and serum nitric oxide (NO), endothelin-1 (ET-1), tumor necrosis factor α (TNF-α), and soluble intercellular adhesion molecule 1 (sICAM-1) were measured.

RESULTSIn comparison with the NOR group, the level of plasma HGF and serum NO, ET-1 and TNF-α, and sICAM-1 in SHG and FHG control groups were all significantly increased (P<0.01); in comparison with the SHG group, plasma HGF and serum NO, ET-1, TNF-α, and sICAM-1 in FHG group were all significantly increased further (P<0.01 or P<0.05); meanwhile, in comparison with the FHG control group, the level of plasma HGF and serum NO, ET-1, TNF-α, and sICAM-1 in PQS and MHC groups were all decreased significantly (P<0.01). However, comparison of the aortic arteries histology among groups showed no significant differences either before or after treatment.

CONCLUSIONBlood glucose fluctuation could facilitate the development of vascular endothelial dysfunction in T2DM rats, while PQS could improve the endothelial function of T2DM rats with high blood glucose fluctuation, which may be related to its effects of relieving vessel stress, decreasing vasoconstrictor ET-1 production, preventing compensated increase of NO, and reducing inflammatory reaction.

Animals ; Aorta ; drug effects ; pathology ; Blood Glucose ; metabolism ; Body Weight ; drug effects ; Diabetes Mellitus, Type 2 ; blood ; drug therapy ; Endothelin-1 ; blood ; Endothelium, Vascular ; drug effects ; physiopathology ; Hepatocyte Growth Factor ; blood ; Intercellular Adhesion Molecule-1 ; blood ; Male ; Nitric Oxide ; blood ; Panax ; chemistry ; Plant Leaves ; chemistry ; Plant Stems ; chemistry ; Rats ; Saponins ; pharmacology ; therapeutic use ; Solubility ; Tumor Necrosis Factor-alpha ; blood

BACKGROUNDObstructive sleep apnea is a frequent medical condition consisting of repetitive sleep-related episodes of upper air ways obstruction and can lead to hypertension. Ang II type 1 receptor (AT1R) played important roles in hypertension since it binds with Ang II, controlling salt-water and blood pressure homeostasis. This study explores rat aorta AT1R expression during intermittent hypoxia (IH) and the signaling pathways involved.

METHODSA rat model and a cell model used a BioSpherix-OxyCycler A84 system and a ProOx C21 system respectively. The arterial blood pressure was recorded by a Nihon Kohden Polygraph System. Immunohistochemic was used to focus and analyze the expression of AT1R in rat aorta. Real-time PCR and Western blotting were used to explore the signaling pathways that participated in AT1R expression.

RESULTSIn this study, we found that chronic intermittent hypoxia (CIH) induced AT1R transcription which increased the blood pressure in rat aorta compared to normoxia and to sustained hypoxia. The AT1R protein expression in the aorta was similar to the real-time PCR results. We explored the signaling mechanisms involved in the AT1R induction in both rat aorta and the aortic endothelial cells by real-time PCR and Western blotting. Compared to normoxia, CIH increased ERK1 mRNA transcription but not ERK2 or p38MAPK in the aorta; whereas sustained hypoxia (SH) upregulated ERK2 but not ERK1 or p38MAPK mRNA. In cells, IH induced AT1R expression with ERK1/2 phosphorylation but reduced p38MAPKs phosphorylation, whereas SH induced only ERK1/2 phosphorylation. The ERK1/2 inhibitor PD98059 attenuated the IHinduced AT1R increase but the p38MAPK inhibitor SB203580 did not.

CONCLUSIONSOur results indicate that CIH induced the elevation of rat blood pressure and aorta AT1R expression. Moreover, AT1R expression in IH and sustained hypoxia might be regulated by different signal transduction pathways, highlighting a novel regulatory function through ERK1/2 signaling in IH.

Animals ; Aorta ; metabolism ; Blood Pressure ; physiology ; Hypoxia ; genetics ; physiopathology ; MAP Kinase Signaling System ; genetics ; physiology ; Male ; Rats ; Rats, Wistar ; Receptor, Angiotensin, Type 2 ; genetics ; metabolism

The present study was designed to investigate the role of opioid receptors in the vasorelaxation effect of chronic intermittent hypobaric hypoxia (CIHH) in thoracic aorta rings and the underlying mechanism in rats. Adult male Sprague-Dawley (SD) rats were randomly divided into 2 groups: CIHH treatment group and control group. The rats in CIHH group were exposed to hypoxia in a hypobaric chamber (simulated 5 000 m altitude) for 28 days, 6 h per day. The rats in control group were kept in the same environment as CIHH rats except no hypoxia exposure. The relaxation of thoracic aorta rings was recorded by organ bath perfusion technique, and expression of opioid receptors was measured by Western blot. Results are shown as follows. (1) The acetylcholine (ACh)-induced endothelium-dependent relaxation of thoracic aorta in CIHH rats was increased obviously in a concentration-dependent manner compared with that in control rats (P < 0.05). (2) This enhancement of ACh-induced relaxation in CIHH rats was abolished by naloxone, a non-specific opioid receptor blocker (P < 0.05). (3) The expressions of δ, μ and κ opioid receptors in thoracic aorta of CIHH rats were up-regulated compared with those in control rats (P < 0.05). (4) The enhancement of CIHH on relaxation of thoracic aorta was reversed by glibenclamide, an ATP-sensitive potassium channel (KATP) blocker (P < 0.05). The results suggest that opioid receptors are involved in CIHH-enhanced ACh-induced vasorelaxation of thoracic aorta through KATP channel pathways.
Acetylcholine ; pharmacology ; Altitude ; Animals ; Aorta, Thoracic ; drug effects ; Glyburide ; pharmacology ; Hypoxia ; physiopathology ; KATP Channels ; antagonists & inhibitors ; Male ; Rats ; Rats, Sprague-Dawley ; Receptors, Opioid ; metabolism ; Vasodilation

AIM: To investigate the effects of pinocembrin on angiotensin II (Ang II)-induced vascular contraction, and to explore its molecular mechanism of actions. METHODS: The isometric vascular tone was measured in rat thoracic aortic rings with denuded endothelium. Phosphorylation level of myosin phosphatase target unit 1 (MYPT1), and protein levels of Rho kinase 1 (ROCK1, ROKβ or p160ROCK) and angiotensin II type-1 receptor (AT1R) were determined by Western blot analysis. RESULTS: Pinocembrin produced a relaxant effect on endothelium-denuded aortic rings contracted by Ang II (100 nmol·L(-1)) in a dose-dependent manner. In endothelium-denuded aortic rings stimulated by Ang II, pretreatment with pinocembrin (25 and 100 μmol·L(-1)) for 20 min significantly attenuated MYPT1 phosphorylation and ROCK1 protein levels. Meanwhile, the protein level of AT1R in response to Ang II was not affected by pinocembrin in rat aortic rings. CONCLUSION These findings indicate that pinocembrin inhibits vasoconstriction induced by Ang II in rat endothelium-denuded aortic rings, and the mechanism at least in part, is due to the blockade of the RhoA/ROCK pathway.
Angiotensin II ; metabolism ; Animals ; Aorta ; drug effects ; enzymology ; metabolism ; physiopathology ; Flavanones ; pharmacology ; In Vitro Techniques ; Male ; Myocardial Contraction ; drug effects ; Rats ; Rats, Sprague-Dawley ; Signal Transduction ; drug effects ; Vasoconstriction ; drug effects ; rho-Associated Kinases ; antagonists & inhibitors ; genetics ; metabolism

The incidence of cardiovascular disease is predicted to increase as the population ages. There is accumulating evidence that arginase upregulation is associated with impaired endothelial function. Here, we demonstrate that arginase II (ArgII) is upregulated in aortic vessels of aged mice and contributes to decreased nitric oxide (NO) generation and increased reactive oxygen species (ROS) production via endothelial nitric oxide synthase (eNOS) uncoupling. Inhibiting ArgII with small interfering RNA technique restored eNOS coupling to that observed in young mice and increased NO generation and decreased ROS production. Furthermore, enhanced vasoconstrictor responses to U46619 and attenuated vasorelaxation responses to acetylcholine in aged vasculature were markedly improved following siRNA treatment against ArgII. These results might be associated with increased L-arginine bioavailability. Collectively, these results suggest that ArgII may be a valuable target in age-dependent vascular diseases.
15-Hydroxy-11 alpha,9 alpha-(epoxymethano)prosta-5,13-dienoic Acid/pharmacology ; Aging ; Animals ; Aorta/enzymology/physiopathology ; Arginase/genetics/*metabolism ; Endothelium, Vascular/*enzymology/physiopathology ; Enzyme Induction ; Gene Knockdown Techniques ; Mice ; Mice, Inbred C57BL ; Nitric Oxide/metabolism ; Nitric Oxide Synthase Type III/*metabolism ; RNA, Small Interfering/genetics ; Reactive Oxygen Species/metabolism ; Up-Regulation ; Vasoconstriction/drug effects

The present study was designed to test the hypothesis that a medium-term simulated microgravity can induce region-specific remodeling in large elastic arteries with their innermost smooth muscle (SM) layers being most profoundly affected. The second purpose was to examine whether these changes can be prevented by a simulated intermittent artificial gravity (IAG). The third purpose was to elucidate whether vascular local renin-angiotensin system (L-RAS) plays an important role in the regional vascular remodeling and its prevention by the gravity-based countermeasure. This study consisted of two interconnected series of in-vivo and ex-vivo experiments. In the in-vivo experiments, the tail-suspended, hindlimb unloaded rat model was used to simulate microgravity-induced cardiovascular deconditioning for 28 days (SUS group); and during the simulation period, another group was subjected to daily 1-hour dorso-ventral (-G(x)) gravitation provided by restoring to normal standing posture (S + D group). The activity of vascular L-RAS was evaluated by examining the gene and protein expression of angiotensinogen (Ao) and angiotensin II receptor type 1 (AT1R) in the arterial wall tissue. The results showed that SUS induced an increase in the media thickness of the common carotid artery due to hypertrophy of the four SM layers and a decrease in the total cross-sectional area of the nine SM layers of the abdominal aorta without significant change in its media thickness. And for both arteries, the most prominent changes were in the innermost SM layers. Immunohistochemistry and in situ hybridization revealed that SUS induced an up- and down-regulation of Ao and AT1R expression in the vessel wall of common carotid artery and abdominal aorta, respectively, which was further confirmed by Western blot analysis and real time PCR analysis. Daily 1-hour restoring to normal standing posture over 28 days fully prevented these remodeling and L-RAS changes in the large elastic arteries that might occur due to SUS alone. In the ex-vivo experiments, to elucidate the important role of transmural pressure in vascular regional remodeling and differential regulation of L-RAS activity, we established an organ culture system in which rat common carotid artery, held at in-vivo length, can be perfused and pressurized at varied flow and pressure for 7 days. In arteries perfused at a flow rate of 7.9 mL/min and pressurized at 150 mmHg, but not at 0 or 80 mmHg, for 3 days led to an augmentation of c-fibronectin (c-FN) expression, which was also more markedly expressed in the innermost SM layers, and an increase in Ang II production detected in the perfusion fluid. However, the enhanced c-FN expression and increased Ang II production that might occur due to a sustained high perfusion pressure alone were fully prevented by daily restoration to 0 or 80 mmHg for a short duration. These findings from in-vivo and ex-vivo experiments have provided evidence supporting our hypothesis that redistribution of transmural pressures might be the primary factor that initiates region-specific remodeling of arteries during microgravity and the mechanism of IAG is associated with an intermittent restoration of the transmural pressures to their normal distribution. And they also provide support to the hypothesis that L-RAS plays an important role in vascular adaptation to microgravity and its prevention by the IAG countermeasure.
Angiotensinogen ; genetics ; metabolism ; Animals ; Aorta, Abdominal ; pathology ; physiopathology ; Carotid Artery, Common ; pathology ; physiopathology ; Hindlimb Suspension ; Male ; Muscle, Smooth, Vascular ; metabolism ; pathology ; RNA, Messenger ; genetics ; metabolism ; Rats ; Rats, Sprague-Dawley ; Receptor, Angiotensin, Type 1 ; genetics ; metabolism ; Renin-Angiotensin System ; physiology ; Weightlessness Simulation