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

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

OBJECTIVETo explore the molecular biological mechanism for tanshinone II A reversing left ventricular hypertrophy, it would be studying the effect of tashinone on the endothelial nitric oxide synthase (eNOS) and protein kinase C (PKC) in the hypertrophic cadiocyte of rats suffered abdominal aorta constriction.

METHODSD rats were operated with abdominal aorta constriction and 8 rats were done with sham surgery. After 4 weeks, all rats were divided into 4 groups: myocardial hypertrophy group, low dose tanshinone II A group (10 mg x kg(-1) x d(-1)), high dose tanshinone II A group (20 mg x kg(-1) x d(-1)) and valsartan group (10 mg x kg(-1) d(-1) intragastric administration). 8 weeks later, the rats were used to measure the left ventricular mass index (LVMI) with the tissue of left ventricle and myocardial fiber dimension (MFD) by pathological section and HE stain, to detect the nitric oxide content by nitrate reductase, to detect the genic expression of eNOS by RT-PCR and to detect the activity of protein kinase C (PKC) by Western blotting.

RESULT1) The blood pressure in group myocardial hypertrophy [(186 +/- 13) mmHg] and tansginone II A [low and high dose (188 +/- 11,187 +/- 14) mmHg] was obviously higher than that in group sham surgery and valsartan group [vs (117 +/- 8, 136 +/- 15) mmHg, P < 0.01]. But there was no difference between group myocardial hypertrophy and group tanshinone II A (low and high dose). 2) The LVMI and MFD were obviously higher in group tanshinone II A low and high dose) and group valsartan than those in group sham surgery (P < 0.05), and lower than those in group myocardial hypertrophy (P < 0.01). 3) The NO level was obviously higher in group tanshinone II A (low and high dose) and group valsartan than that in group myocardial hypertrophy (12.78 +/- 1.66, 11.95 +/- 1.39, 12.26 +/- 2.08 vs 5.83 +/- 1.06) micromol x L(-1), (P < 0.01 ), and lower than that in group sham surgery (vs 19.35 +/- 1.47) micromol x L(-1), (P < 0.05). 4) The expressive level of eNOS mRNA and protein in myocardial hypertrophy group was less than that in other groups (P < 0.01). And valsartan group was less than tanshinone II A groups and sham surgery group (P < 0.05), but there were no difference among the two tanshinone II A groups and sham surgery group. 5) The level of PKC protein in group myocardial hypertrophy was obviously higher than that in all the other groups (1.291 +/- 0.117 vs 0.563 +/- 0.094, 0.605 +/- 0.051, 0.519 +/- 0.062, 0.827 +/- 0.086, P < 0.01), and the level in group valsartan was higher than that in group sham operation and group tanshinone II A (low and high dose).

CONCLUSIONNO/NOS system in local myocardium has close relationship with the pathological process for myocardial hypertrophy. Tanshinone II A can produce the pharmacological action to reverse myocardial hypertrophy by inhibiting the activity of PKC and promoting the genic expression of eNOS in local myocardium and the production of endogenous NO.

Animals ; Aorta, Abdominal ; pathology ; Benzofurans ; pharmacology ; Blood Pressure ; drug effects ; Cardiomyopathy, Hypertrophic ; complications ; enzymology ; physiopathology ; Constriction, Pathologic ; complications ; Dose-Response Relationship, Drug ; Drugs, Chinese Herbal ; pharmacology ; Endothelium, Vascular ; drug effects ; enzymology ; Female ; Gene Expression Regulation, Enzymologic ; drug effects ; Heart Ventricles ; drug effects ; metabolism ; pathology ; physiopathology ; Male ; Myocytes, Cardiac ; drug effects ; enzymology ; pathology ; Nitric Oxide ; metabolism ; Nitric Oxide Synthase ; genetics ; metabolism ; Protein Kinase C ; metabolism ; RNA, Messenger ; genetics ; metabolism ; Rats

Hypertension is associated with endothelial dysfunction and increased cardiovascular risk. Caveolin-1 regulates nitric oxide (NO) signaling by modulating endothelial nitric oxide synthase (eNOS). The purpose of this study was to examine whether HMG-CoA reductase inhibitor improves impaired endothelial function of the aorta in spontaneous hypertensive rat (SHR) and to determine the underlying mechanisms involved. Eight-week-old male SHR were assigned to either a control group (CON, n=11) or a rosuvastatin group (ROS, n=12), rosuvastatin (10 mg/kg/day) administered for eight weeks. Abdominal aortic rings were prepared and responses to acetylcholine (10-9-10-4 M) were determined in vitro. To evaluate the potential role of NO and caveolin-1, we examined the plasma activity of NOx, eNOS, phosphorylated-eNOS and expression of caveolin-1. The relaxation in response to acetylcholine was significantly enhanced in ROS compared to CON. Expression of eNOS RNA was unchanged, whereas NOx level and phosphorylated-eNOS at serine-1177 was increased accompanied with depressed level of caveolin-1 in ROS. We conclude that 3-Hydroxy-3-methylglutaryl Coenzyme-A (HMG-CoA) reductase inhibitor can improve impaired endothelial dysfunction in SHR, and its underlying mechanisms are associated with increased NO production. Furthermore, HMG-CoA reductase inhibitor can activate the eNOS by phosphorylation related to decreased caveolin-1 abundance. These results imply the therapeutic strategies for the high blood pressure-associated endothelial dysfunction through modifying caveolin status.
Acetylcholine/metabolism ; Animals ; Aorta/metabolism/physiopathology ; Blood Pressure/drug effects ; Caveolin 1/*metabolism ; Down-Regulation ; Drug Administration Schedule ; Endothelium, Vascular/*drug effects/physiopathology ; Fluorobenzenes/administration & dosage/*pharmacology ; Hydroxymethylglutaryl-CoA Reductase Inhibitors/administration & dosage/*pharmacology ; Hypertension/enzymology/metabolism/*physiopathology ; Male ; Nitric Oxide/blood ; Nitric Oxide Synthase Type III/*metabolism ; Phosphorylation ; Pyrimidines/administration & dosage/*pharmacology ; Rats ; Rats, Inbred SHR ; Sulfonamides/administration & dosage/*pharmacology ; Vasodilation/drug effects

Plasma sphingomyelin (SM) has been shown to be an independent risk factor for coronary heart disease, and sphingomyelin synthase 2 (SMS2) contributes to de novo SM biosynthesis and plasma membrane SM levels. The aim of the present study is to evaluate the in vivo role of SMS2 deficiency in serum SM metabolism and atherosclerosis (AS) development. We used male SMS2 knockout (SMS2(-/-)) and C57BL/6J (wild-type, WT) mice as experimental and control groups, respectively. Each group was fed high-fat diet (1% cholesterol, 20% leaf fat), as well as bile salt for accelerating the atherosclerotic formation. After three months of feeding, the mice were killed to observe aortic arches and oil red-stained longitudinal sections of thoracoabdominal aortae. Fasting blood samples were taken from the tail vein before and after high-fat diet, and the serum lipid and SM levels were measured by using kits and enzymatic method respectively. Western blot was used to analyze the contents of nuclear factor-kappaB (NFkappaB) p65 subunit in peritoneal macrophages stimulated with lipopolysaccharide (LPS) after high-fat diet. The results showed that after high-fat diet, SMS2(-/-) mice presented decreased atherosclerotic lesions in aortic arch and thoracoabdominal aorta compared with WT mice. Regardless of whether high-fat diet were given or not, SMS2(-/-) mice showed a significant decrease in serum SM level (P<0.05), but no significant changes in serum lipid levels, compared with WT mice. The expressions of NFkappaB p65 were attenuated in macrophages from SMS2(-/-) mice in response to LPS stimulation compared with those of the WT mice. These results suggest that SMS2 deficiency decreases AS and inhibits inflammation in mice. Thus, SMS2 deficiency may be a potential therapeutic strategy.
Animals ; Aorta ; pathology ; Atherosclerosis ; metabolism ; physiopathology ; prevention & control ; Diet, High-Fat ; Dietary Fats ; administration & dosage ; Gene Knockout Techniques ; Inflammation ; prevention & control ; Macrophages, Peritoneal ; enzymology ; pathology ; Male ; Mice ; Mice, Inbred C57BL ; Mice, Knockout ; NF-kappa B ; metabolism ; Sphingomyelins ; blood ; Transferases (Other Substituted Phosphate Groups) ; genetics

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