In this study, we used a rat model of pulmonary arterial hypertension (PAH) induced by monocrotaline (MCT) to investigate the role and mechanism of angiotensin (Ang)-(1-7) in regulating pulmonary artery diastolic function. Three weeks after subcutaneous injection of MCT or normal saline, the right ventricular systolic pressure (RVSP) and right ventricular hypertrophy index (RVHI) of rats were detected using a right heart catheter. Vascular endothelium-dependent relaxation was evaluated by acetylcholine (ACh)-induced vasodilation. The relaxation function of vascular smooth muscle was evaluated by sodium nitroprusside (SNP)-induced vasodilation. Human pulmonary artery endothelial cells (HPAECs) were incubated with Ang-(1-7) to measure nitric oxide (NO) release levels. The results showed that compared with control rats, RVSP and RVHI were significantly increased in the MCT-PAH rats, and both ACh or SNP-induced vasodilation were worsened. Incubation of pulmonary artery of MCT-PAH rats with Ang-(1-7) (1 × 10^-9-1 × 10^-4 mol/L) caused significant vaso-relaxation. Pre-incubation of Ang-(1-7) in the pulmonary artery of MCT-PAH rats significantly improved ACh-induced endothelium-dependent relaxation, but had no significant effect on SNP-induced endothelium-independent relaxation. In addition, Ang-(1-7) treatment significantly increased NO levels in HPAECs. The Mas receptor antagonist A-779 inhibited the effects of Ang-(1-7) on endothelium-dependent relaxation and NO release from endothelial cells. The above results demonstrate that Ang-(1-7) promotes the release of NO from endothelial cells by activating Mas receptor, thereby improving the endothelium-dependent relaxation function of PAH pulmonary arteries.
Rats ; Humans ; Animals ; Vasodilation ; Pulmonary Arterial Hypertension ; Monocrotaline/toxicity* ; Rats, Sprague-Dawley ; Hypertension, Pulmonary/chemically induced* ; Endothelial Cells ; Pulmonary Artery ; Endothelium ; Acetylcholine/pharmacology* ; Nitroprusside/pharmacology*

Iron accumulation in the brain is associated with the pathogenesis of Parkinson's disease (PD). Misexpression of some iron transport and storage proteins is related to iron dyshomeostasis. Iron regulatory proteins (IRPs) including IRP1 and IRP2 are cytosolic proteins that play important roles in maintaining cellular iron homeostasis. F-box and leucine-rich repeat protein 5 (FBXL5) is involved in the regulation of iron metabolism by degrading IRP2 through the ubiquitin-proteasome system. Nitric oxide (NO) enhances the binding activity of IRP1, but its effect on IRP2 is ambiguous. Therefore, in the present study, we aim to determine whether sodium nitroprusside (SNP), a NO donor, regulates FBXL5 and IRP2 expression in cultured SH-SY5Y cells. MTT assay revealed that treatment of SNP attenuated the cell viability in a dose-dependent manner. Flow cytometry test showed that 100 and 300 μmol/L SNP administration significantly reduced the mitochondrial membrane potential by 45% and 60%, respectively. Moreover, Western blotting analysis demonstrated that 300 μmol/L SNP significantly increased FBXL5 expression by about 39%, whereas the expression of IRP2 was decreased by 46%, correspondingly. These findings provide evidence that SNP could induce mitochondrial dysfunction, enhance FBXL5 expression and decrease IRP2 expression in SH-SY5Y cells.
Cell Line ; Cell Survival ; F-Box Proteins ; metabolism ; Homeostasis ; Humans ; Iron Regulatory Protein 2 ; metabolism ; Nitric Oxide ; metabolism ; Nitroprusside ; pharmacology ; Proteasome Endopeptidase Complex ; Ubiquitin ; metabolism ; Ubiquitin-Protein Ligase Complexes ; metabolism

SRT1720, a new discovered drug, was reported to activate silent information regulator 1 (SIRT1) and inhibit the chondrocyte apoptosis. However, the underlying mechanism remains elusive. In the present study, the chondrocytes were extracted from the cartilage tissues of New Zealand white rabbits, cultured in the presence of sodium nitroprusside (SNP) (2.5 mmol/L) and divided into five groups: 1, 5, 10, and 20 μmol/L SRT1720 groups and blank control group (0 μmol/L SRT1720). MTT assay was used to detect the chondrocyte viability and proliferation, and DAPI staining and flow cytometry to measure the chondrocyte apoptosis. The expression levels of SIRT1, p53, NF-κB/p65, Bax, and peroxisome proliferator-activated receptor gamma coactivator 1-α (PGC-1α) were detected by Western blotting and the expression levels of SIRT1, type II collagen, and aggrecan mRNA by RT-PCR. The results showed that in the SRT1720-treated groups, the nuclei of chondrocytes were morphologically intact and had uniform chromatin. In the blank control group, nuclear rupture into debris was observed in chondrocytes. With the SRT1720 concentration increasing, the chondrocyte viability increased, the apoptosis rate decreased, the protein expression levels of SIRT1 and PGC-1α and the mRNA expression levels of type II collagen and aggrecan increased ({ptP}<0.05), and the expression levels of p53, NF-κB and bax decreased (P<0.05). It was suggested that SRT1720 inhibits chondrocyte apoptosis by activating the expression of SIRT1 via p53/bax and NF-κB/PGC-1α pathways.
Aggrecans ; genetics ; metabolism ; Animals ; Apoptosis ; drug effects ; Cartilage, Articular ; cytology ; drug effects ; metabolism ; Cell Proliferation ; drug effects ; Cell Survival ; drug effects ; Chondrocytes ; cytology ; drug effects ; metabolism ; Chromatin ; chemistry ; drug effects ; metabolism ; Collagen Type II ; genetics ; metabolism ; Gene Expression Regulation ; Heterocyclic Compounds, 4 or More Rings ; pharmacology ; Nitroprusside ; toxicity ; Peroxisome Proliferator-Activated Receptor Gamma Coactivator 1-alpha ; genetics ; metabolism ; Primary Cell Culture ; Rabbits ; Signal Transduction ; drug effects ; genetics ; Sirtuin 1 ; genetics ; metabolism ; Transcription Factor RelA ; genetics ; metabolism ; Tumor Suppressor Protein p53 ; genetics ; metabolism ; bcl-2-Associated X Protein ; genetics ; metabolism

OBJECTIVETo explore targets of Chinese herbal medicine at cellular and molecular leve1s through an experimental study on Yinxingye Capsule (YC) intervening vascular endothelial cell apoptoeis of hyperhornocysteinemia (HHcy) rats.

METHODSThe HHcy model was prepared in male Wistar rats. Totally 42 rats were randomly divided into 4 groups, i.e., the control group (n =10), the model group (n = 11), the YC group (n =11), the folic acid group (n =10). Carboxy methyl cellulose (CMC) solution (1%) was administered to rats in the control group by gastrogavage.3% methionine suspension at 1. 5 g/kg was administered to rats in the model group by gastrogavage. 3% methionine suspension at 1. 5 g/kg and folic acid suspension at 0. 06 g/kg was administered to rats in the folic acid group by gastrogavage. 3% methionine suspension at 1. 5 g/kg and YC at 0. 02 g/kg was administered to rats in the YC group by gastrogavage. Morphological changes of aortic tissue were observed by hematoxylin eosin (HE) staining. The plasma homocysteine (Hcy) level was detected in each group. The endothelium-dependent diastolic functions of the thoracic aorta on different concentrations of sodium nitroprusside (SNP) and acetylcholine (Ach) were detected. Gene expressions of Bcl-2-associated X protein (BAX), inducible nitric oxide synthase (iNOS), c-Fos, cellular inhibitor of apoptosis protein 2 (c-IAP2) were detected by real time polymerase chain reaction (RT-PCR).

RESULTSPathological results showed that thickening aortic endothelium, swollen and desquamated endothelial cells. Few foam cells could be seen in the model group. Myoma-like proliferation of smooth muscle cells in tunica media could also be seen. These pathological changes were milder in the YC group and the folic acid group. Compared with the control group, plasma Hcy levels increased in the model group (P <0. 05). The endothelium-dependent diastolic rates at 10(-6) and 10(-4)mol/L Ach and 10(-7) -10(-3)mol/L SNP all decreased in the model group (P <0. 01, P <0. 05). Gene expressions of Bax, c-Fos, and iNOS increased, but c-IAP2 gene expressions decreased in the model group (all P <0. 05). Compared with the model group, plasma Hcy levels decreased in the YC group and the folic acid group (P <0. 05). The endothelium-dependent diastolic rates increased in the YC group and the folic acid group at various SNP concentrations except 10(-6) mol/L SNP in the folic acid group. The endothelium-dependent diastolic rates increased in the YC group and the folic acid group at 10(-6) and 10(-4)mol/L Ach (all P <0. 05). Gene expressions of Bax, c-Fos, and iNOS decreased in the YC group and the folic acid group, but c-IAP2 gene expression increased in the folic acid group (all P <0. 05).

CONCLUSIONYC could reduce plasma Hcy levels, down-regulate gene expressions of Bax, c-Fos, and iNOS, thereby reducing apoptosis of vascular endothelial cells, improving vascular endothelial function, and delaying atherosclerotic process.

Acetylcholine ; Animals ; Aorta ; Aorta, Thoracic ; Apoptosis ; drug effects ; Drugs, Chinese Herbal ; pharmacology ; therapeutic use ; Endothelial Cells ; Endothelium, Vascular ; Hyperhomocysteinemia ; drug therapy ; Male ; Nitric Oxide Synthase Type II ; Nitroprusside ; Proto-Oncogene Proteins c-fos ; Rats ; Rats, Wistar ; bcl-2-Associated X Protein

OBJECTIVEIn our study, the function of the third-order branches of the mesentenc artery was measured by microvascular ring technique, which can be used to detect microvascular function in some disease related to microvascular dysfunction.

METHODSIsolated, fixed, standardized and then activated the third-order branches of rat mesenteric artery. Microvascular tone was measured by systolic and diastolic drags respectively, with the help of DMT tension apparatus and PowerLab data acquisition system.

RESULTSThe third-order branches of rat mesenteric artery showed excellent response to vasoactive drugs. The contraction effect of norepinephrine (NE) reached 19 in mN. When acetylcholine (Ach) or sodium nitroprusside (SNP) of 10(9)-10(5)mol/L was added, vascular tones showed gradient drop: 80% of maximal relaxation when adding ACh, while 95% of maximal relaxation when adding SNP.

CONCLUSIONThe third-order branches of the mesenteric artery function was successfully detected by using microvascular ring technique.

Acetylcholine ; pharmacology ; Animals ; In Vitro Techniques ; Male ; Mesenteric Arteries ; drug effects ; physiology ; Nitroprusside ; pharmacology ; Norepinephrine ; pharmacology ; Rats ; Vasoconstrictor Agents ; pharmacology ; Vasodilation ; physiology ; Vasodilator Agents ; pharmacology

OBJECTIVETo investigate the effects of microvesicles (MVs) derived from hypoxia/reoxygenation (H/R)-treated human umbilical vein endothelial cells (HUVECs) on endothelium-dependent relaxation of rat thoracic aortic rings.

METHODSH/R injury model was established to induce HUVECs to release H/R-EMVs. H/R-EMVs from HUVECs were isolated by ultracentrifugation from the conditioned culture medium. H/R-EMVs were characterized using 1 μm latex beads and anti-PE-CD144 by flow cytometry. Thoracic aortic rings of rats were incubated with 2.5, 5, 10, 20 μg/ml H/R-EMVs derived from H/R-treated HUVECs for 4 hours, and their endothelium-dependent relaxation in response to acetylcholine (ACh) or endothelium-independent relaxation in response to sodium nitroprusside (SNP) was recorded in vitro. The nitric oxide (NO) production of ACh-treated thoracic aortic rings of rats was measured using Griess reagent. The expression of endothelial NO synthase (eNOS) and phosphorylated eNOS (p-eNOS, Ser-1177) in the thoracic aortic rings of rats was detected by Western blotting. Furthermore, the levels of SOD and MDA in H/R-EMVs-treated thoracic aortic rings of rats were measured using SOD and MDA kit.

RESULTSH/R-EMVs were induced by H/R-treated HUVECs and isolated by ultracentrifugation. The membrane vesicles (< 1 μm) induced by H/R were CD144 positive. ACh-induced relaxation and NO production of rat thoracic aortic rings were impaired by H/R-EMVs treatment in a concentration-dependent manner (P < 0.05, P < 0.01). The expression of total eNOS (t-eNOS) was not affected by H/R-EMVs. However, the expression of p-eNOS decreased after treated with H/R-EMVs. The activity of SOD decreased and the level of MDA increased in H/R-EMVs treated rat thoracic aortic rings (P < 0.01).

CONCLUSIONACh induced endothelium-dependent relaxation of thoracic aortic rings of rats was impaired by H/R-EMVs in a concentration-dependent manner. The mechanisms included a decrease in NO production, p-eNOS expression and an increase in oxidative stress.

Acetylcholine ; pharmacology ; Animals ; Aorta, Thoracic ; physiology ; Cell Hypoxia ; Endothelium, Vascular ; physiology ; Human Umbilical Vein Endothelial Cells ; cytology ; Humans ; In Vitro Techniques ; Nitric Oxide ; metabolism ; Nitric Oxide Synthase Type III ; metabolism ; Nitroprusside ; pharmacology ; Oxidative Stress ; Rats

This study is to investigate the effect of Vam3, a dimeric derivative of resveratrol, on SNP-induced apoptosis and its potential mechanism in rat articular chondrocytes. Isolated rat articular chondrocytes were treated with sodium nitroprusside (SNP), a NO donor, to induce apoptosis. Apoptosis percentage was evaluated by Annexin V-PI and nucleus fracture was examined by DAPI staining. Level of intracellular reactive oxygen species (ROS) was detected using 2, 7'-dichlorofluorescin diacetate (DCFH-DA) as a fluorescence probe by fluorescence microplate reader. The change in mitochondrial membrane potential was detected by TMRE staining. Expressions of SIRT1, acetylated p53 (ac-p53), cleaved caspase 9 and cleaved caspase 3 were determined by Western blotting. It showed that Vam3 up to 10 micromol x L(-1) could significantly reduce SNP-induced rat articular chondrocytes apoptosis (P < 0.01) and nucleus fracture, inhibit the increase of intracellular ROS level (P < 0.01) and reverse the decrease in mitochondrial membrane potential (P < 0.01). Simultaneously, Vam3 could upregulate the expression of SIRT1, deacetylate p53, and inhibit the cleavage of caspase 9 and caspase 3 (P < 0.01) of rat articular chondrocytes exposed to SNP. This study indicates Vam3 could protect rat articular chondrocytes against SNP-induced apoptosis, perhaps through the upregulation of SIRT1 and deacetylation of p53.
Animals ; Apoptosis ; drug effects ; Arabidopsis Proteins ; pharmacology ; Cartilage, Articular ; cytology ; Caspase 3 ; metabolism ; Caspase 9 ; metabolism ; Cells, Cultured ; Chondrocytes ; cytology ; metabolism ; Male ; Membrane Potential, Mitochondrial ; drug effects ; Nitric Oxide Donors ; antagonists & inhibitors ; pharmacology ; Nitroprusside ; pharmacology ; Qa-SNARE Proteins ; pharmacology ; Rats ; Rats, Wistar ; Reactive Oxygen Species ; metabolism ; Sirtuin 1 ; metabolism ; Tumor Suppressor Protein p53 ; metabolism

OBJECTIVETo study the effects of Geniposide on SNP(sodium nitroprusside)-induced apoptosis of chondrocyte in vitro and cell cycle.

METHODSThe chondrocyte of three-week-old SD rats were separated and cultivated. The second generation of chondrocyte cells were involved in experiment. Chondrocyte proliferation was measured by assay; flow cytometer were adopted to observe cell cycle and apoptosis rate; NO examination adopted nitrate reductase method.

RESULTSGeniposide could significantly decrease the percentage of SNP-induced chondrocytes in G0/G1 phase and increased percentage in S phase and G2/M phase. The apoptosis of chondrocyte and the concentration of NO in the culture supernatants was reduced significantly (r=0.917, P<0.01).

CONCLUSIONGeniposide could impact SNP-induced apoptosis of chondrocyte by reducing the concentration of NO in the culture supernatants, promoting proliferation of chondrocytes, which is a probable and important mechanism of Geniposide preventing osteoarthritis.

Animals ; Apoptosis ; drug effects ; Cell Cycle ; drug effects ; Chondrocytes ; drug effects ; physiology ; Female ; Iridoids ; pharmacology ; therapeutic use ; Male ; Nitroprusside ; pharmacology ; Osteoarthritis ; drug therapy ; Rats ; Rats, Sprague-Dawley

Effective drug to manage constipation has been unsatisfactory. We sought to determine whether methionine has effect on the human colon. Human colon tissues were obtained from the specimens of colon resection. Microelectrode recording was performed and contractile activity of muscle strips and the propagation of the contractions in the colon segment were measured. At 10 microM, methionine depolarized the resting membrane potential (RMP) of circular muscle (CM) cells. In the CM strip, methionine increased the amplitude and area under the curve (AUC) of contractions. In the whole segment of colon, methionine increased the amplitude and AUC of the high amplitude contractions in the CM. These effects on contraction were maximal at 10 microM and were not observed in longitudinal muscles in both the strip and the colon segment. Methionine reversed the effects of pretreatment with sodium nitroprusside, tetrodotoxin and Nw-oxide-L-arginine, resulting in depolarization of the RMP, and increased amplitude and AUC of contractions in the muscle strip. Methionine treatment affected the wave pattern of the colon segment by evoking small sized amplitude contractions superimposed on preexisting wave patterns. Our results indicate that a compound mimicking methionine may provide prokinetic functions in the human colon.
Area Under Curve ; Arginine/pharmacology ; Colon/drug effects/physiology ; Humans ; Membrane Potentials/drug effects ; Methionine/*pharmacology ; Microelectrodes ; Muscle Contraction/*drug effects ; Muscle, Smooth/drug effects/*physiology ; Nitroprusside/pharmacology ; Tetrodotoxin/pharmacology

OBJECTIVETo investigate the impact of sodium nitroprusside (a nitric oxide donor) in the ductus arteriosus in preterm rabbits on hydrogen sulfide (H(2)S)-cystathionine-γ-lyase (CSE) system.

METHODSFor 16 Japanese white rabbits pregnant for 21 days were randomly divided into four groups, each of the following groups had 4 rabbits: control group, intraperitoneal injection of sodium nitroprusside 1 mg/kg, 2.5 mg/kg, and 5.0 mg/kg groups. The rabbits in control group had a peritoneal puncture with a simple hollow needle, and those in the other groups were given corresponding dose of intraperitoneal injection of sodium nitroprusside at gestational age 23 and 25 days, respectively. At gestational age 26 days the fetuses of the pregnant rabbits were removed surgically, and 28 fetal rabbits were obtained from the control group, 27 from the sodium nitroprusside small dose group, 29 from the medium dose group, and 26 from the large dose group. The fetal heart blood sample of 1 ml was taken from each fetus, and immediately after sampling the arterial ductal tissues were dissected. Fetal rabbit plasma proteins hydrogen sulfide content was determined by using de-protein method, and real time quantitative RT-PCR was used for determination of arterial tissue CSE gene and western-blotting was used for measuring protein expression of CSE.

RESULTSIn control group hydrogen sulfide content of fetal rabbits plasma (55.68 ± 6.57) µmol/L and arterial tissue CSE mRNA expression was 1.07 ± 4.12; the parameters in intraperitoneal injection of sodium nitroprusside group 1 mg/kg were (60.02 ± 6.09) µmol/L and 3.46 ± 0.18; in intraperitoneal injection of sodium nitroprusside group 2.5 mg/kg, were (64.71 ± 7.12) µmol/L and 10.95 ± 0.22; and in intraperitoneal injection of sodium nitroprusside group 1 mg/kg were (70.63 ± 8.07) µmol/L and 19.56 ± 0.17. Comparison between small dose group and control group, medium dose group and small dose group, high dose group and medium dose group showed that the above data were significantly different P < 0.05, with the injection of sodium nitroprusside CSE protein expression increased gradually with increasing doses.

CONCLUSIONSodium nitroprusside showed an enhancing effect on preterm CSE-H(2)S system in rabbit ductus arteriosus in a certain range of concentration in a dose-dependent manner.

Animals ; Cystathionine gamma-Lyase ; blood ; Ductus Arteriosus ; metabolism ; Female ; Hydrogen Sulfide ; blood ; Nitric Oxide ; blood ; Nitroprusside ; administration & dosage ; pharmacology ; Pregnancy ; Rabbits