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*

In this study, we investigated the effects of Panax notoginseng saponins (PNS) on pulmonary vascular remodeling and ADAM10/Notch3 pathway in pulmonary arterial hypertension (PAH). PAH rat model was established, and male Sprague Dawley (SD) rats were randomly divided into control group, monocrotaline (MCT) group and MCT+PNS group, with 10 rats in each group. Rats in the control group were intraperitoneally injected with equal volume of normal saline. Rats in the MCT group was injected intraperitoneally with 60 mg/kg MCT on the first day, and then with the same volume of normal saline every day. Rats in the MCT+PNS group was injected intraperitoneally with 60 mg/kg MCT on the first day, and then with 50 mg/kg PNS every day. The modeling time of each group lasted for 21 days. After the model was established, the mean pulmonary artery pressure (mPAP) was measured by right heart catheterization technique, the right ventricular hypertrophy index (RVHI) was calculated, the microscopic morphology and changes of pulmonary vascular wall were observed by HE and Masson staining, and the expressions of ADAM10, Notch3, Hes-1, P27, PCNA, Caspase-3 proteins and mRNA in pulmonary vascular tissue of rats were detected by Western blot and qPCR. The expression and localization of Notch3 and α-SMA were detected by immunofluorescence staining. The protein expression of ADAM10 was detected by immunohistochemical staining. The results showed that compared with the control group, mPAP, RVHI, pulmonary vessels and collagen fibers in the MCT group were significantly increased, the expressions of ADAM10, Notch3, Hes-1, and PCNA protein and mRNA were significantly increased, while the expressions of P27 and Caspase-3 protein and mRNA were decreased significantly. Compared with the MCT group, mPAP and RVHI were significantly decreased, pulmonary vessels were significantly improved and collagen fibers were significantly reduced, the expressions of protein and mRNA of ADAM10, Notch3, Hes-1, and PCNA were decreased in MCT+PNS group, but the expressions of protein and mRNA of P27 and Caspase-3 were increased slightly. The results of immunofluorescence showed that Notch3 and α-SMA staining could overlap, which proved that Notch3 was expressed in smooth muscle cells. The expression of Notch3 in the MCT group was increased significantly compared with that in the control group, while PNS intervention decreased the expression of Notch3. Immunohistochemical staining showed that compared with the control group, the amount of ADAM10 in the MCT group was increased significantly, and the expression of ADAM10 in the MCT+PNS group was decreased compared with the MCT group. These results indicate that PNS can improve the PAH induced by MCT in rats by inhibiting ADAM10/Notch3 signaling pathway.
Animals ; Male ; Rats ; Caspase 3/metabolism* ; Collagen ; Disease Models, Animal ; Hypertension, Pulmonary/drug therapy* ; Monocrotaline/adverse effects* ; Panax notoginseng/chemistry* ; Proliferating Cell Nuclear Antigen/pharmacology* ; Pulmonary Arterial Hypertension ; Pulmonary Artery/metabolism* ; Rats, Sprague-Dawley ; Receptor, Notch3/genetics* ; RNA, Messenger ; Saline Solution ; Signal Transduction ; Saponins/pharmacology*

OBJECTIVE: To explore the therapeutic mechanism of tanshinone IIA in the treatment of pulmonary arterial hypertension (PAH) in rats. METHODS: A total of 100 male SD rats were randomized into 5 groups (n=20), and except for those in the control group with saline injection, all the rats were injected with monocrotaline (MCT) on the back of the neck to establish models of pulmonary hypertension. Two weeks after the injection, the rat models received intraperitoneal injections of tanshinone IIA (10 mg/kg), phosphatidylinositol 3 kinase (PI3K) inhibitor (1 mg/kg), both tanshinone IIA and PI3K inhibitor, or saline (model group) on a daily basis. After 2 weeks of treatment, HE staining and α-SMA immunofluorescence staining were used to evaluate the morphology of the pulmonary vessels of the rats. The phosphorylation levels of PI3K, protein kinase B (PKB/Akt) and endothelial nitric oxide synthase (eNOS) in the lung tissue were determined with Western blotting; the levels of eNOS and NO were measured using enzyme-linked immunosorbent assay (ELISA). RESULTS: The results of HE staining and α-SMA immunofluorescence staining showed that tanshinone IIA effectively inhibited MCT-induced pulmonary artery intimamedia thickening and muscularization of the pulmonary arterioles (P < 0.01). The results of Western blotting showed that treatment with tanshinone IIA significantly increased the phosphorylation levels of PI3K, Akt and eNOS proteins in the lung tissue of PAH rats; ELISA results showed that the levels of eNOS and NO were significantly decreased in the rat models after tanshinone IIA treatment (P < 0.01). CONCLUSION Treatment with tanshinone IIA can improve MCT-induced pulmonary hypertension in rats through the PI3K/Akt-eNOS signaling pathway.
Abietanes ; Animals ; Hypertension, Pulmonary/drug therapy* ; Male ; Monocrotaline/toxicity* ; Nitric Oxide Synthase Type III/therapeutic use* ; Phosphatidylinositol 3-Kinase/pharmacology* ; Phosphatidylinositol 3-Kinases/metabolism* ; Proto-Oncogene Proteins c-akt/metabolism* ; Pulmonary Artery ; Rats ; Rats, Sprague-Dawley ; Signal Transduction

Hepatic sinusoidal obstruction syndrome (HSOS) via exposure to pyrrolizidine alkaloids (PAs) is with high mortality and there is no effective treatment in clinics. Bear bile powder (BBP) is a famous traditional animal drug for curing a variety of hepatobiliary diseases such as cholestasis, inflammation, and fibrosis. Here, we aim to evaluate the protective effect of BBP against HSOS induced by senecionine, a highly hepatotoxic PA compound. Our results showed that BBP treatment protected mice from senecionine-induced HSOS dose-dependently, which was evident by improved liver histology including reduced infiltration of inflammatory cells and collagen positive cells, alleviated intrahepatic hemorrhage and hepatic sinusoidal endothelial cells, as well as decreased conventional serum liver function indicators. In addition, BBP treatment lowered matrix metalloproteinase 9 and pyrrole-protein adducts, two well-known markers positively associated with the severity of PA-induced HSOS. Further investigation showed that BBP treatment prevents the development of liver fibrosis by decreasing transforming growth factor beta and downstream fibrotic molecules. BBP treatment also alleviated senecionine-induced liver inflammation and lowered the pro-inflammatory cytokines, in which tauroursodeoxycholic acid played an important role. What's more, BBP treatment also decreased the accumulation of hydrophobic bile acids, such as cholic acid, taurocholic acid, glycocholic acid, as well. We concluded that BBP attenuates senecionine-induced HSOS in mice by repairing the bile acids homeostasis, preventing liver fibrosis, and alleviating liver inflammation. Our present study helps to pave the way to therapeutic approaches of the treatment of PA-induced liver injury in clinics.
Animals ; Bile ; Bile Acids and Salts ; Endothelial Cells/metabolism* ; Hepatic Veno-Occlusive Disease/pathology* ; Inflammation/pathology* ; Liver Cirrhosis/drug therapy* ; Mice ; Powders ; Pyrrolizidine Alkaloids/adverse effects* ; Ursidae

This study aims to develop a UPLC-MS/MS method for simultaneous determination of six pyrrolizidine alkaloids(PAs)--intermedine N-oxide(ImNO), lycopsamine N-oxide(LyNO), seneciphylline(Sp), seneciphylline N-oxide(SpNO), senecionine N-oxide(SnNO), and senkirkine(Sk) in different parts of Emilia sonchifolia. UPLC conditions are as follows: ACQUITY UPLC HSS T3 column(2.1 mm×100 mm, 1.8 μm), mobile phase consisting of 0.05% formic acid and 2.5 mmol·L~(-1) ammonium formate in water(A)-0.05% formic acid and 2.5 mmol·L~(-1) ammonium formate in acetonitrile(B) for gradient elution. MS conditions are as below: electrospray ionization(ESI) in the positive ion mode, multiple reaction monitoring(MRM), and the content of the six PAs was calculated with the external standard method. The results suggested the differences in the six PAs among different parts of E. sonchifolia. Sk was detected in all the four parts, with similar content. SnNO also existed in all the four parts, but the content in roots was significantly higher than that in other parts. Sp and SpNO were found in both roots and flowers, with the content higher in the former than in the later. ImNO and LyNO were only found in leaves, and the content was low. Among the six components detected, ImNO, LyNO, and SpNO were found and determined for the first time, which enriched the toxic components and laid a scientific basis for the quality and safety evaluation of E. sonchifolia.
Asteraceae ; Chromatography, High Pressure Liquid ; Chromatography, Liquid ; Pyrrolizidine Alkaloids ; Tandem Mass Spectrometry

Pyrrolizidine alkaloids(PAs) are a group of naturally occurring alkaloids with a pyrrolizidine skeleton which can be found in about 3% of the world's flowering plants. It is notorious that PAs are cause the hepatoxic and genotoxic-carcinogenic effects by taking PA-containing herbs, food and dietary supplements. In order to control the poisoning caused by PAs, European Medicines Agency has set a limit of intake of PAs from herbal medicinal products at 0.007 μg of 1,2-unsaturated PAs/kg body weight. Nonetheless, a systematic overview of the amount of PAs in the herb has not been provided. Therefore, this paper is to systematically review the current status of PAs content analysis of herbal medicines and foods reported in the literature, and to provide theoretical and experimental support for the safety risk assessment and control of PAs in Chinese herbal medicines.
Food ; Herbal Medicine ; Phytotherapy ; Plants, Medicinal ; Pyrrolizidine Alkaloids/toxicity*

Pyrrolizidine alkaloids(PAs) are a kind of natural toxins, which can cause severe hepatotoxicity, pulmonary toxicity, genotoxicity, neurotoxicity, embryotoxicity and even death. Therefore, international organizations and countries such as World Health Organization have paid great attention to herbal medicines and preparations containing PAs. PAs are widely distributed in Chinese herb medicines and contained in hundreds of traditional Chinese medicine preparations. The content of adonifoline, the main PAs in Senecionis Scandentis Herba, shall be less than 0.004% in herbal medicines as described in Chinese pharmacopeia. However, there is no guidance in preparations which contain Senecionis Scandentis Herba. In this study, 14 preparations were analyzed by an UPLC-MS method. Among them, 8 preparations were found to contain adonifoline much higher than the content limits of such countries as Germany, Netherlands and New Zealand. And the highest contents of adonifoline were found in Qianbai Biyan Tablets and Qianbai Biyan Capsules, which are officially recorded in Chinese Pharmacopeia. The contents of adonifoline varied in different batches of the same preparations. The highest content was 156.10 μg·g~(-1) Qianbai Biyan Tablets, whose daily intake of adonifoline was up to 1 030.26 μg according to the recommended dosage of the preparation. Our results showed the potential risk of these preparations, and the content limit of adonifoline shall be inspected Chinese medicine preparations containing Senecionis Scandentis Herba.
Chromatography, Liquid ; Drugs, Chinese Herbal/standards* ; Lactones/analysis* ; Medicine, Chinese Traditional ; Pyrrolizidine Alkaloids/analysis* ; Senecio/chemistry* ; Tandem Mass Spectrometry

In vascular smooth muscle, K⁺ channels, such as voltage-gated K⁺ channels (Kv), inward-rectifier K⁺ channels (Kir), and big-conductance Ca²⁺-activated K⁺ channels (BK(Ca)), establish a hyperpolarized membrane potential and counterbalance the depolarizing vasoactive stimuli. Additionally, Kir mediates endothelium-dependent hyperpolarization and the active hyperemia response in various vessels, including the coronary artery. Pulmonary arterial hypertension (PAH) induces right ventricular hypertrophy (RVH), thereby elevating the risk of ischemia and right heart failure. Here, using the whole-cell patch-clamp technique, we compared Kv and Kir current densities (I(Kv) and I(Kir)) in the left (LCSMCs), right (RCSMCs), and septal branches of coronary smooth muscle cells (SCSMCs) from control and monocrotaline (MCT)-induced PAH rats exhibiting RVH. In control rats, (1) I(Kv) was larger in RCSMCs than that in SCSMCs and LCSMCs, (2) I(Kv) inactivation occurred at more negative voltages in SCSMCs than those in RCSMCs and LCSMCs, (3) I(Kir) was smaller in SCSMCs than that in RCSMCs and LCSMCs, and (4) I(BKCa) did not differ between branches. Moreover, in PAH rats, I(Kir) and I(Kv) decreased in SCSMCs, but not in RCSMCs or LCSMCs, and I(BKCa) did not change in any of the branches. These results demonstrated that SCSMC-specific decreases in I(Kv) and I(Kir) occur in an MCT-induced PAH model, thereby offering insights into the potential pathophysiological implications of coronary blood flow regulation in right heart disease. Furthermore, the relatively smaller I(Kir) in SCSMCs suggested a less effective vasodilatory response in the septal region to the moderate increase in extracellular K⁺ concentration under increased activity of the myocardium.
Animals ; Coronary Vessels ; Heart Diseases ; Heart Failure ; Hyperemia ; Hypertension ; Hypertrophy, Right Ventricular ; Ischemia ; Membrane Potentials ; Monocrotaline ; Muscle, Smooth ; Muscle, Smooth, Vascular ; Myocardium ; Myocytes, Smooth Muscle ; Patch-Clamp Techniques ; Potassium Channels ; Rats ; Septum of Brain

BACKGROUND AND OBJECTIVES: Elevated endothelin (ET)-1 level is strongly correlated with the pathogenesis of pulmonary arterial hypertension (PAH). Expression level of nicotinamide adenine dinucleotide phosphate oxidase (NOX) 4 is increased in the PAH patients. Ambrisentan, a selective endothelin receptor A (ERA) antagonist, is widely used in PAH therapy. The current study was undertaken to evaluate the effects of ambrisentan treatment in the monocrotaline (MCT)-induced PAH rat model. METHODS: Rats were categorized into control group (C), monocrotaline group (M) and ambrisentan group (Am). The M and Am were subcutaneously injected 60 mg/kg MCT at day 0, and in Am, ambrisentan was orally administered the day after MCT injection for 4 weeks. The right ventricle (RV) pressure was measured and pathological changes of the lung tissues were observed by Victoria blue staining. Protein expressions of ET-1, ERA, endothelial nitric oxide synthase (eNOS) and NOX4 were confirmed by western blot analysis. RESULTS: Ambrisentan treatment resulted in a recovery of the body weight and RV/left ventricle+septum at week 4. The RV pressure was lowered at weeks 2 and 4 after ambrisentan administration. Medial wall thickening of pulmonary arterioles and the number of intra-acinar arteries were also attenuated by ambrisentan at week 4. Protein expression levels of ET-1 and eNOS were recovered at weeks 2 and 4, and ERA levels recovered at week 4. CONCLUSIONS: Ambrisentan administration resulted in the recovery of ET-1, ERA and eNOS protein expression levels in the PAH model. However, the expression level of NOX4 remained unaffected after ambrisentan treatment.
Animals ; Arteries ; Arterioles ; Blotting, Western ; Body Weight ; Endothelin Receptor Antagonists ; Endothelins ; Gene Expression ; Heart Ventricles ; Humans ; Hypertension ; Hypertension, Pulmonary ; Lung ; Models, Animal ; Monocrotaline ; NADP ; NADPH Oxidase ; Nitric Oxide Synthase Type III ; Oxidoreductases ; Rats ; Receptors, Endothelin ; Victoria

OBJECTIVES: Elevated pulmonary pressure and right ventricular (RV) dysfunction are the hallmarks of pulmonary vascular disease in animal models and human patients with pulmonary arterial hypertension (PAH). Monocrotaline models of PAH are widely used to study the pathophysiology of PAH. The purpose of this study was to evaluate the severity of PAH rat model by tissue Doppler imaging (TDI). METHODS: PAH was induced in Sprague-Dawley rats by monocrotaline (M) group. The peak systolic (s'), early diastolic (e'), and late diastolic myocardial velocities (a') were measured using TDI at basal segments. Tricuspid annular plane systolic excursion (TAPSE) was measured in the 4-chamber view. Velocity of a tricuspid regurgitation (TR) jet was measured to estimate the pulmonary artery pressure to assess the severity of PAH. RESULTS: Decrease in the RV shortening fraction and ejection fraction were observed in the M group compared with the control (C) group. RV e' velocity and s' velocity were significantly lower in the M group compared with the C group. The TAPSE was significantly lower in the M group compared with the C group (1.26±0.22 mm vs. 2.83±0.34 mm). The TR velocity was significantly higher in the M group compared with the C group (4.48±0.34 m/sec vs. 1.23±0.02 m/sec). CONCLUSION: TAPSE is an easily obtainable, widely recognized and clinically useful echocardiographic parameter of global RV function in the PAH rat model. We recommend that TDI would be a helpful diagnostic tool to evaluate the RV function in PAH rat model.
Animals ; Echocardiography ; Humans ; Hypertension ; Hypertension, Pulmonary ; Models, Animal ; Monocrotaline ; Pulmonary Artery ; Rats ; Rats, Sprague-Dawley ; Tricuspid Valve Insufficiency ; Vascular Diseases ; Ventricular Dysfunction, Right ; Ventricular Function, Right