OBJECTIVETo establish a mouse model of abdominal aorta stenosis and analyze the alterations in the arterial wall response to high and low shear stress.

METHODSTwenty mouse were randomized equally into 4 groups, including 3 test groups (1, 7 and 14 day groups) with surgically induced stenosis of the abdominal aorta, and a sham-operated group without stenosis. The hemodynamics and the internal diameter of the blood vessel were measured by color Doppler flow imaging. The wall shear stress was calculated by Poiseiulle hydrodynamics formula (τ(m)=η×4×V(m)/D). Pathological examination and immunohistochemistry were performed to observe the arterial morphological changes and the endothelial vascular cell adhesion molecule-1 (VCAM-1) expression. The intimal-media thickness of the aorta was measured and endothelial VCAM-1 expression analyzed quantitatively.

RESULTSRegions of low and high flow shear stress were created upstream from the stenosis and within the stenosis, respectively. Compared with the sham-operated group, the mice with aorta stenosis showed gradually increased vascular intimal-media thickness and VCAM-1 expression intensity in the upstream aorta, but not within the regions of the stenosis.

CONCLUSIONVascular remodeling may occur shortly after exposure to low shear stress, which plays a significant role in initiation and progression of the pathological process of atherosclerosis mediated by VCAM-1, whereas high shear stress may exert an anti-atherosclerotic effect.

Animals ; Aorta, Abdominal ; metabolism ; pathology ; physiopathology ; Aortic Valve Stenosis ; physiopathology ; Atherosclerosis ; physiopathology ; Constriction ; Hemodynamics ; Male ; Mice ; Shear Strength ; physiology ; Stress, Mechanical ; Vascular Cell Adhesion Molecule-1 ; metabolism

OBJECTIVETo explore the elastic lamina degradation and the collagen remodeling of aortic artery as well as oxides stress and inflammation of the apolipoprotein (Apo E) deficient mice with or without experimental hypertension.

METHODSEighty male Apo E deficient mice were fed with high-fat diet beginning at six weeks of age. At 8-week old, they were randomly divided into hypertension group and control group (n=40 each), the mice in hypertension group were subjected the suprarenal aortic constriction operation and then randomly divided into two subgroups: 15 weeks age and 30 weeks age groups. At the end of experiment, the vascular elastic lamina degradation and the content of collagen were determined by morphological method, plasma ICAM-1 level was measured by ELISA, and the rennin activity measured by radioimmunoassay, the superoxide anion detected by fluorescence, the MOMA-2 observed by immunofluorescence in all animals. mRNA expression of NF-κB P65 and MMP9 was detected by real-time PCR.

RESULTIn 15-week old group, the elastic lamina degradation Grade II and the intima-media thickness in the hypertension group were significantly higher than in the control group [(5.4±3.3)% vs. (8.9±2.5)%, P<0.05; (98.66±18.90) µm vs. (70.08±11.71) µm, P<0.05]. In 30-week old group, the elastic lamina degradation Grade III, the III type of collagen and the intima-media thickness were also significantly higher than in the control group [(15.2±3.7)% vs. (8.1±3.3)%, P<0.01; (23.00±7.73)% vs. (11.00±3.82)%, P<0.05; (147.31±22.60) µm vs. (103.98±17.21) µm, P<0.01]. The level of ICAM-1 in hypertension group was significantly higher than that of control group in both 15-week old and in 30-week old mice [(46.3±3.7) µg/ml vs. (40.6±5.7) µg/ml, P<0.05; (56.0±3.1) µg/ml vs. (45.2±2.8) µg/ml, P<0.05]. The superoxide anion, the MOMA-2, mRNA expression of NF-κB P65 and MMP9 in the hypertension group were significantly higher than in the control group in both 15-week old and in the 30-week old mice. The increase in hypertension group was more pronounced in the 30-week old mice than in the 15-week old mice.

CONCLUSIONThe elastic lamina degradation and the collagen remodeling of aortic artery as well as oxides stress and inflammation are more significant in the Apo E deficient mice with hypertension than in control Apo E deficient mice.

Animals ; Aorta ; physiopathology ; Apolipoproteins E ; genetics ; Collagen ; metabolism ; Hypertension ; metabolism ; pathology ; Inflammation ; pathology ; Male ; Mice ; Mice, Knockout ; Oxidative Stress

The present study investigated the interaction between sodium loading and enalapril on renin synthesis and secretion in hydronephrotic mice. Four different experimental groups (n=10 each) were used: sham-operated animals with normal diet (control group); sodium loading (SL group); enalapril treatment with normal diet (E group), and sodium loading combined with enalapril treatment (SL+E group). The hydronephrotic left kidney was induced by unilateral ureteral ligation in mice in the latter three groups. Plasma renin concentration (PRC) in the aorta, both the left and right renal veins, tissue renin concentration (TRC) and renin mRNA levels in the kidneys were examined under different procedures. In hydronephrotic mice treated with sodium loading, PRC in the left and right renal veins was lower than that in control mice (P<0.05), and TRC and renin mRNA levels in the hydronephrotic kidney were also suppressed (P<0.05). In hydronephrotic mice treated with enalapril, there were significant increases in PRC, TRC and renin mRNA levels in the hydronephrotic and right kidneys compared to the normal control (P<0.01). In hydronephrotic animals treated with sodium loading and enalapril, the increasing response was attenuated, and PRC in the hydronephrotic vein was similar to the level in the aorta. There was an interaction between sodium loading and enalapril on renin-angiotensin system (RAS) in both hydronephrotic and normal kidneys. The mechanism in control of renin synthesis is independent of the macula densa, but the latter is critical in the control of renin secretion.
Animals ; Aorta ; metabolism ; Enalapril ; pharmacology ; Hydronephrosis ; metabolism ; Kidney ; physiopathology ; Mice ; Mice, Inbred BALB C ; RNA, Messenger ; metabolism ; Renin ; metabolism ; Renin-Angiotensin System ; drug effects ; Sodium ; metabolism

OBJECTIVETo investigate the differentially expressed genes in rat in the process of regression of vascular calcification by using the suppression subtractive hybridization (SSH).

METHODS24 SD male rats which aged 6 weeks and specific pathogen free grade were selected and randomly divided into 3 groups (n = 8): control group, calcification group and regression group respectively. Vascular calcification model (vitamin D3 plus nicotine, VDN) were made from rats in calcification group and regression group, and rats in control group were intragastric administered with normal saline and lavaged with peanut oil. Rats were bred for 8 weeks in calcification group and control group, while rats in regression group were fed for 16 weeks. All rats were killed to measure concentration of calcium in the arterial tissue and examine the pathological lesion changes. Subtractive hybridization among vascular cDNA sequences from calcification group and regression group were established. The cDNA fragments which expressed higher or lower in regression group than those in calcification group were isolated. Differentially expressed genes with cDNA fragment were inserted into PMD18-T plasmid vector and transformed competent DH-5alpha, cDNA libraries of differentially expressed gene between calcification group and regression group were then constructed. Recombinant vectors were analyzed by colony PCR, positive genes were randomly selected for sequencing and analyzed by BLAST. 4 genes were randomly selected for RT-PCR certification combined with semi-quantitative analysis of DNA bands.

RESULTSVDN model of rats were successfully constructed. Concentration of tissue calcium in calcification group (15.34 mg/g +/- 2.51 mg/g) was significantly increased compared to that in control group (5.20 mg/g +/- 0.75 mg/g, P < 0.001), while in comparison with calcification group (15.34 mg/g +/- 2.51 mg/g), calcium in regression group was relatively lower (12.73 mg/g +/- 1.89 mg/g, P < 0.05). 28 up-regulated genes and 22 down-regulated genes were gained through sequencing and BLAST analysis among positive clones. RT-PCR validation indicated that 4 genes such as prdx3 and Ank2 had increasedly expressed in regression group than those in calcification group, the average fold change was 1.7.

CONCLUSIONRat vascular calcification tissue had characteristic of active regression. Genes in relation to pyrophosphoric acid synthesis, glutamate signal peptides, anti-oxidant and ant-apoptosis were up-regulated, at the same time many genes related to ossification and oxidation activity were down-regulated in the process of calcification regression. Increased expression of calcification suppressor genes accompanying decreased expression of calcification promoting genes might be the intrinsic mechanisms which initiated the active regression of calcified tissues.

Animals ; Aorta ; metabolism ; pathology ; Gene Expression Profiling ; Gene Expression Regulation ; Male ; Rats ; Rats, Sprague-Dawley ; Vascular Calcification ; genetics ; physiopathology

The aim of the present study was to investigate the alterations in thoracic aortic vasomotor function in rats with chronic heart failure (CHF) post myocardial infarction (MI), and then explored the possible mechanism of pathological changes. Male Sprague-Dawley rats were divided into sham and CHF groups randomly. The CHF model group of rats was generated by ligating the left anterior descending artery. In sham-operated rats the ligation was placed but not tightened. A total of 20 rats underwent either sham-operated (n=8) or surgery for MI (n=12). All sham-operated rats survived the surgical procedure and the post-surgical period, whereas total mortality among MI-rats was 25% (3 out of 12). Only MI-rats with infarct-size >30% of the left ventricle (LV) were included for analysis (8 out of 9). Ten weeks after surgery, rats were anaesthetized for hemodynamic measurements, which contains systolic pressure, diastolic pressure, left ventricular systolic pressure (LVSP), left ventricular end diastolic pressure (LVEDP), LV+dp/dt(max) and LV-dp/dt(max). After that hearts were rapidly excised and weighed. Myocardial infarct size was determined by triphenyltetrazolium chloride (TTC) staining method. Isolated thoracic artery ring preparations were studied in a wire-myograph. The arterial constrictive responses to KCl, CaCl2, phenylephrine (PE), and caffeine and the arterial diastolic responses to acetylcholine (ACh) were recorded by the Multi Myograph System. To explore the possible mechanism, nitric oxide synthase (NOS) inhibitor N-nitrl-L-arginine methylester (L-NAME) and non-selective cyclooxygenase (COX) inhibitor indomethacin (Indo) were used. The results obtained were as follows: (1) CHF group showed an increased contraction response to KCl (5-100 mmol/L) and PE (1x10(-8)-3x10(-4) mol/L), and a reduced endothelium-dependent relaxation response to ACh (1x10(-12)-1x10(-4) mol/L) compared with those observed in sham group (P<0.01, P<0.05); (2) In the presence of L-NAME (1 mmol/L), the endothelium-dependent cumulative contractions to ACh (1x10(-7)-1x 10(-4) mol/L) was significantly enhanced in CHF group (P<0.05), and this effect was reversed by pretreatment with Indo (10 mumol/L); (3) In CHF group, the vessels incubated with Indo (10 mumol/L) showed an increased vasodilation induced by ACh (1x10(-12)-1x10(-4) mol/L) (P<0.05); (4) In the Ca(2+)-free K-H solution, calcium-dependent contraction curves induced by CaCl2 (1x10(-4)-3x10(-2) mol/L) in CHF group significantly shifted to the left compared with sham group (P<0.05); while the vascular contraction induced by caffeine (30 mmol/L) had no significant changes. These findings suggest that thoracic arteries of rats with CHF have endothelial dysfunction, and the contribution of endothelial dilation and contraction was significantly altered in CHF rats. The mechanism could be partly associated with the increased endothelium-dependent contracting factors by COX pathway, or the increased extracellular Ca(2+) influx through voltage-operated channels, thus leading to elevated vasoconstriction.
Animals ; Aorta, Thoracic ; physiopathology ; Chronic Disease ; Endothelins ; metabolism ; Endothelium, Vascular ; physiopathology ; Heart Failure ; etiology ; physiopathology ; Male ; Myocardial Infarction ; complications ; Prostaglandin-Endoperoxide Synthases ; metabolism ; Rats ; Rats, Sprague-Dawley ; Vasomotor System ; physiopathology

OBJECTIVETo observe the effects of Coptis Chinensis on vasoconstrictive activity of isolated thoracic aorta rings of normoxic and chronic intermittent hypobaric hypoxic (CIHH) rats, and to investigate the underlying mechanisms.

METHODSYoung male Sprague-Dawley rats were randomly divided into normoxic group and CIHH group: the fonnrmer were not given any special treatment; the latter were exposed to hypoxia in a hypobaric chamber simulating 5000 m altitude (PB = 404 mmHg, PO2 = 84 mmHg, 11.1% O2), 6 hours daily for 28 days. The isolated thoracic aorta rings of rats were prepared and perfused in thermostat, and the effects of Coptis on vasoconstrictive activity of aorta rings were recorded, the mechanisms were investigated simultaneouly.

RESULTSCoptis Chinensis significantly decreased NE and KC-induced vasoconstriction of normoxic and CIHH rats' isolated aortic rings, but the inhibitive effects had no obvious discrepancy between the two groups. The contractive amplitude had no marked change after the removal of endothelium. When calculated by Logit Loglinear analysis, IC50 of NE and KCl-induced contractive amplitude in normoxic group were respectively 2.99 g/L and 6.14 g/L, while they were 3.45 g/L and 5.81 g/L in CIHH group. The inhibitive effect of Coptis on vasoconstrictive activity of both groups could be partly decreased by Glibenclamide and nitro-L-arginine methyl ester; Indomethacin suppressed the effect on normoxic group as well. Also Coptis significantly inhibited NE-induced both intracellular and extracellular calciumion-depended vasoconstriction.

CONCLUSIONCoptis Chinensis obviously relaxes isolated thoracic aorta rings of normoxic and CIHH rats, but the effects are endothelium-independent and have no marked discrepancy between the two groups. The mechanisms of the effects may be related to the opening of ATP-sensitive K+ channel, raise of nitric oxide concentration in both groups, and the increasing of PGI2 in normoxic group. Besides, Coptis may inhibit sarcoplasmic reticulum releasing Ca2+ and decrease the inflow of extracellular Ca2+ via cell membrane.

Animals ; Aorta, Thoracic ; physiopathology ; Calcium ; metabolism ; Coptis ; chemistry ; Drugs, Chinese Herbal ; pharmacology ; Hypoxia ; physiopathology ; In Vitro Techniques ; KATP Channels ; drug effects ; Male ; Rats ; Rats, Sprague-Dawley ; Vasoconstriction ; drug effects

OBJECTIVETo observe the changes of vascular endothelial functions and general neuro-endocrine-immunity (NEI) network under the state of qi-deficiency syndrome induced by excessive idleness and to approach their internal relevance and illuminate initially the pathophysiological mechanism of vascular lesion induced by excessive idleness.

METHODSA total of 100 male Wistar rats were randomly divided into the control group and the qi-deficiency syndrome model group, 50 rats in each group. The qi-deficiency syndrome model was established by feeding the animals with hyper-alimentation diet in combination with restricting movement for 10 weeks. Changes of common chemical signal molecules related to NEI and vascular endothelial functions were measured by the end of the experiment. Furthermore, their internal relevance was analyzed by the method of canonical correlation analysis.

RESULTSThe vascular endothelial structure and function were obviously injured in the model group. Compared with the control group, the chemical signal molecules, such as 5-hydroxytryptamine (5-HT), corticosterone (CORT), triiodothyronine (T3), tetraiodothyronine (T4), angiotensin II (Ang II), interleukin-1 (IL-1), and tumor necrosis factor-alpha (TNF-alpha) in peripheral blood of the model group (n=43) were changed significantly (P<0.05 or P<0.01). Canonical correlation analysis showed that vascular endothelial dysfunction was correlated to the changes of these signal molecules in the NEI network.

CONCLUSIONSComfort-based lifestyle induced not only vascular endothelial dysfunction but also an imbalance of the NEI network. Vascular endothelial dysfunction and the imbalanced NEI network interacted with each other, and an imbalance of the NEI network may be the pathophysiologic basis for the genesis and development of vascular endothelial dysfunction, even diseases of the blood vessel.

Animals ; Aorta ; metabolism ; pathology ; physiopathology ; ultrastructure ; Biomarkers ; analysis ; metabolism ; Cardiovascular Diseases ; etiology ; metabolism ; pathology ; physiopathology ; Disease Models, Animal ; Endothelins ; metabolism ; Endothelium, Vascular ; metabolism ; pathology ; physiopathology ; Immune System ; metabolism ; pathology ; physiology ; Male ; Neuroimmunomodulation ; physiology ; Neurosecretory Systems ; metabolism ; pathology ; physiology ; Nitric Oxide ; metabolism ; Qi ; Rats ; Rats, Wistar ; Sedentary Lifestyle ; Syndrome ; Yin Deficiency ; etiology ; metabolism ; pathology ; physiopathology

The present study is aimed to investigate the effect of chronic intermittent hypobaric hypoxia (CIHH) on contractile activities in isolated thoracic aorta and pulmonary artery rings and the underlying mechanism in rats. Sprague-Dawley (SD) rats were randomly divided into 4 groups: control group (CON), 14 days CIHH treatment group (CIHH14), 28 days CIHH treatment group (CIHH28) and 42 days CIHH treatment group (CIHH42). CIHH rats were exposed to hypoxia in a hypobaric chamber simulating 5 000 m altitude, 6 h daily for 14, 28 and 42 d, respectively. After artery rings were prepared from pulmonary artery and thoracic aorta, the contractile activity of the artery rings was recorded using organ bath technique. Results are shown as follows. (1) There were no significant differences of noradrenaline (NA)- and KCl-induced contractions in thoracic aorta and pulmonary artery rings among CIHH and CON rats. (2) Angiotensin Ⅱ (ANGⅡ)-induced contraction in thoracic aorta rings, not in pulmonary artery rings, of CIHH rats was decreased compared with that in CON rats. There was no significant difference of ANGⅡ-induced contraction in thoracic aorta rings among CIHH rats. (3) Inhibitory effect of CIHH on ANGⅡ-induced contraction in thoracic aorta rings was endothelium-independent, and was reversed by glibenclamide (Gli), an ATP-sensitive potassium channels (K(ATP)) blocker, and L-NAME, a NO synthase inhibitor, but not by indomethacin (Indo), a cyclooxygenase inhibitor. These results suggest that CIHH attenuates the contraction induced by ANGⅡ in thoracic aorta rings of rat, which is related to the opening of K(ATP) channel and the increased production of NO.
Angiotensin II ; pharmacology ; Animals ; Aorta, Thoracic ; physiopathology ; Hypoxia ; physiopathology ; KATP Channels ; metabolism ; Male ; Muscle Contraction ; physiology ; Muscle, Smooth, Vascular ; physiopathology ; Nitric Oxide ; biosynthesis ; Pulmonary Artery ; physiopathology ; Rats ; Rats, Sprague-Dawley ; Vasoconstriction ; physiology

OBJECTIVETo observe the changes of aortic endothelium-dependent vasodilation function (EDVR) and expressions of endothelial nitric oxide synthase (eNOS), phosphatidylinositol 3-kinase (PI3K), and protein kinase B (PKB) in insulin-resistance (IR) and type 2 diabetic rats.

METHODSIR rat model was established by feeding 4-6 week-old male SD rats with high glucose and cholesterol diet for 6 weeks and type 2 diabetes (DM) were induced by intraperitoneal injection with low dose streptozotocin (STZ) to IR rats. Glucose infusion rate (GIR) was determined by euglycemic hyperinsulinemic clamp technique, EDVR by acetylcholine (Ach)-induced vasodilation response in isolated aortic rings, aortic NO concentration by Griess Reaction, activation of eNOS detected by immunohistochemical SP method, mRNA expressions of eNOS-, PI3K- and PKB of aorta were assayed by RT-PCR, aorta ultrastructure observed by electron microscopy. Body weight, fast plasma glucose (FPG), insulin (FINS), triglyceride (TG), cholesterol (TC) were determined and the insulin sensitivity index (ISI) was calculated.

RESULTS(1) Body weight, FINS, TG and TC levels were significantly higher while ISI and GIR significantly lower in IR and DM rats than that in normal control rats (P < 0.05). (2) Aorta EDVR decreased significantly in IR and DM group compared with that in control group (P < 0.05) and EDVR was also significantly reduced in DM rats than that in IR rats (P < 0.05). The maximum Ach-induced vasodilation response (EDVR(max), P < 0.01) was positively correlated with ISI and negatively correlated with FPG, TG, TC and FINS (P < 0.01). (3) Aortic NO concentration, the mRNA expressions of eNOS-, PI3K-, and PKB and eNOS immunohistochemical expression in aorta were significantly lower in IR and DM rats compared with normal control rats and the decrease was more pronounced in DM rats (P < 0.05 vs. IR). (4) Pathologic aortic ultrastructure changes were also visualized in IR and DM rats.

CONCLUSIONOur results suggest that reduced NO concentration and expression as well as reduced PI3K-, PKB-, and eNOS mRNA expressions might contributed to the reduced EDVR function and related pathological ultrastructure changes in IR and DM rats.

Animals ; Aorta ; metabolism ; physiopathology ; Diabetes Mellitus, Experimental ; metabolism ; physiopathology ; Diabetes Mellitus, Type 2 ; metabolism ; physiopathology ; Endothelium, Vascular ; metabolism ; physiopathology ; Insulin Resistance ; Male ; Nitric Oxide Synthase Type III ; metabolism ; Phosphatidylinositol 3-Kinases ; metabolism ; Proto-Oncogene Proteins c-akt ; metabolism ; Rats ; Rats, Sprague-Dawley ; Vasodilation

Transmural electrical heterogeneity plays an important role in the normal dispersion of repolarizaion and propagation of excitation in the heart. The amplification of transmural electrical heterogeneity contributes to the genesis of arrhythmias in cardiac hypertrophy and failure. We established a mouse model with cardiac failure by aortic banding and investigated the possible contribution of L-type calcium current (I(Ca-L)) to transmural electrical heterogeneity in both normal and failing hearts. Single myocytes were enzymatically isolated from subendocardial and subepicardial myocardium of the free left ventricle wall. The recordings of action potential and I(Ca-L) were performed using the conventional whole-cell patch-clamp technique. The results showed that: (1) The action potential duration at 90% repolarization (APD(90)) of the subendocardial myocytes in normal control mice was (38.2 +/- 6.44) ms, which was significantly longer than that of the subepicardial myocytes [(15.672 +/- 5.31) ms]. The ratio of APD(90) for subendocardial/subepicardial myocytes was about 2.5:1. The peak I(Ca-L) density in subendocardial myocytes was (-2.7 +/- 0.49) pA/pF, which was not different from that in subepicardial myocytes [(-2.54 +/- 0.53) pA/pF]. (2) In failing hearts, both action potential duration at 50% repolarization (APD(50)) and APD(90) were remarkably prolonged either in subendocardial or subepicardial myocytes compared to that in sham hearts. The subendocardial myocytes had much longer APD. The ratio of APD(90) for subendocardial/subepicardial myocytes changed to about 4.2:1. (3) I(Ca-L) density in subendocardial myocytes was significantly decreased in failing hearts compared with that in sham hearts. At four test potentials from +10 mV to +40 mV, the density of I(Ca-L) from subendocardial myocytes in failing hearts was decreased by 20.2%, 21.4%, 21.6% and 25.7%, respectively (P<0.01). However, no significant difference was observed in I(Ca-L) density from subepicardial myocytes in failing hearts. There was no significant difference in the kinetic properties of I(Ca-L) in subendocardial and subepicardial myocytes between the band and sham groups. We conclude that I(Ca-L) may not contribute to the physiological transmural electrical heterogeneity in mouse hearts. The electrical heterogeneity is exaggerated and the density of I(Ca-L) is decreased in the subendocardial myocytes, but not in the subepicardial myocytes in failing hearts. The results obtained suggest that the decreased density of I(Ca-L) in subendocardial myocytes is possibly an adaptive response to the prolongation of action potential due to delayed depolarization and may reduce the transmural dispersion of repolarization in heart failure.
Action Potentials ; physiology ; Animals ; Aorta, Thoracic ; Calcium Channels, L-Type ; metabolism ; Constriction ; Disease Models, Animal ; Heart Failure ; etiology ; physiopathology ; Mice ; Myocardium ; metabolism ; Patch-Clamp Techniques ; Pressure ; Random Allocation