Shou-Bao Wang

Cardioprotective effect of salvianolic acid A on isoproterenol-induced myocardial infarction in rats.

The present study was designed to evaluate the cardioprotective potential of salvianolic acid A on isoproterenol-induced myocardial infarction in rats. Hemodynamic parameters and lead II electrocardiograph were monitored and recorded continuously. Cardiac marker enzymes and antioxidative parameters in serum and heart tissues were measured. Assay for mitochondrial respiratory function and histopathological examination of heart tissues were performed. Isoproterenol-treated rats showed significant increases in the levels of lactate dehydrogenase, aspartate transaminase, creatine kinase and malondialdehyde and significant decreases in the activities of superoxide dismutase, catalase and glutathione peroxidase in serum and heart. These rats also showed declines in left ventricular systolic pressure, maximum and minimum rate of developed left ventricular pressure, and elevation of left ventricular end-diastolic pressure and ST-segment. In addition, mitochondrial respiratory dysfunction characterized by decreased respiratory control ratio and ADP/O was observed in isoproterenol-treated rats. Administration of salvianolic acid A for a period of 8 days significantly attenuated isoproterenol-induced cardiac dysfunction and myocardial injury and improved mitochondrial respiratory function. The protective role of salvianolic acid A against isoproterenol-induced myocardial damage was further confirmed by histopathological examination. The results of our study suggest that salvianolic acid A possessing antioxidant activity has a significant protective effect against isoproterenol-induced myocardial infarction.

Coptisine protects rat heart against myocardial ischemia/reperfusion injury by suppressing myocardial apoptosis and inflammation

OBJECTIVE Protecting the heart from myocardial ischemia and reperfusion (I/R) damage is the focus of intense research. Coptisine is an isoquinoline alkaloid isolated from Coptidis Rhizoma. The present study investigated the potential effect of coptisine on myocardial I/R damage in rats and the underlying mechanisms. METHODS AND RESULTS Electrocardiogram examination showed that the administration of coptisine 10 min before ischemia significantly decreased I/R-induced arrhythmia after 30 min ischemia followed by 3 h reperfusion. The release of cardiac markers was also limited. Echocardiography was performed before ischemia and 24 h post-I/R, separately. The M-mode records showed that the reductions of ejection fraction (EF) and fractional shortening (FS) were attenuated in coptisine-treated rats compared with the I/R rats. Similar results were obtained with Evans Blue/triphenyl tetrazolium chloride (TTC) staining, in which coptisine notably reduced infarct size. Moreover, terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) assay demonstrated coptisine suppressed myocardial apoptosis, which may be related to the upregulation of Bcl-2 protein and inhibition of caspase-3 activation. Coptisine treatment also attenuated the proinflammatory cytokines including interleukin (IL)-1β, IL-6, and tumor necrosis factor-α in heart tissue. Additionally, Western blot and immunohistochemical analysis showed that coptisine markedly reduced Rho, Rho-kinase 1 (ROCK1), and ROCK2 expression and attenuated the phosphorylation of myosin phosphatase targeting subunit-1, a downstream target of ROCK. CONCLUSIONS Coptisine exerts pronounced cardioprotection in rats subjected to myocardial I/R likely through suppressing myocardial apoptosis and inflammation by inhibiting the Rho/ROCK pathway.

Coptisine exert cardioprotective effect through anti-oxidative and inhibition of RhoA/Rho kinase pathway on isoproterenol-induced myocardial infarction in rats

OBJECTIVE Because myocardial infarction is a major cause of morbidity and mortality worldwide, protecting the heart from the ischemia is the focus of intense research. Coptisine is an isoquinoline alkaloid extracted form Coptidis Rhizoma. This study aims to elucidate if coptisine is responsible for cardioprotection using myocardial infarction (MI) rat models and investigate its potential mechanism of action. METHODS Myocardial infarction was produced in rats with 85 mgkg(-1) isoproterenol administered subcutaneously twice at an interval of 24 h. The rats were randomized into 7 groups: (I) Normal; (II) ISO; (III) ISO+fasudil; (IV) ISO+isosorbide dinitrate (ISDN) and (V-VII) ISO+coptisine (25, 50 and 100 mgkg(-1)). Cardiac function and markers of cardiac ischemic were assessed after MI. RESULTS Rats pretreated with coptisine (25, 50 and 100 mgkg(-1)) for 21 days and received subcutaneously injected with ISO (85 mgkg(-1)) on the 20th and 21st day at an interval of 24 h. The results suggested that coptisine has strong antioxidant activity, and it can maintain cell membrane integrity, ameliorate mitochondrial respiratory dysfunction, reduce myocardial cells apoptosis, inhibit RhoA/ROCK expression induced by high-dose isoproterenol administration. CONCLUSIONS Coptisine provided cardioprotection in a model of myocardial infarction, and therefore should be considered as a novel adjunctive therapy for attenuating myocardial damage.

Effect of salvianolic acid A on vascular reactivity of streptozotocin-induced diabetic rats.

AIMS The present study aims to evaluate the beneficial effect of salvianolic acid A (SAA) on the alterations in vascular reactivity of streptozotocin (STZ)-induced diabetic rats. MAIN METHODS Diabetes was induced by a single intraperitoneal injection of STZ (60 mg/kg). Following 16 weeks of SAA treatment (1 mg/kg/day), thoracic aortic rings of rats were mounted in organ baths. Contractile responses to noradrenaline (NA) and KCl and relaxant responses to acetylcholine (ACh) and sodium nitroprusside (SNP) were assessed. KEY FINDINGS Loss of weight, hyperglycemia, elevated content of malondialdehyde (MDA) and decline of total antioxidant capacity (TAC) were observed in diabetic rats. SAA could reverse these metabolic and biochemical abnormalities. Compared to the control, the maximum contraction (E(max)) to NA, but not sensitivity (pD(2)), increased significantly in diabetic aortas, which was prevented by SAA treatment. However, the response of rat aortas to KCl (E(max) and pD(2)) was not altered either in diabetic group or SAA treatment compared with that of normal control group. We also observed the significant decrease in relaxation to ACh rather than SNP in diabetic group compared with controls, and SAA treatment could revert the ACh response. SIGNIFICANCE It is concluded that oral administration of SAA can significantly improve glucose metabolism and inhibit oxidative injury as well as protect against impaired vascular responsiveness in STZ-induced diabetic rats.

Inhibitory Effects of Brazilin on the Vascular Smooth Muscle Cell Proliferation and Migration Induced by PDGF-BB

Abnormal vascular smooth muscle cell (VSMC) proliferation and migration contribute to the pathogenesis of vascular diseases including atherosclerosis and restenosis. Brazilin isolated from the heartwood of Caesalpinia sappan L. has been reported to exhibit various biological activities, such as anti-platelet aggregation, anti-inflammation, vasorelaxation and pro-apoptosis. However, the functional effects of Brazilin on VSMCs remain unexplored. The present study investigated the potential effects of Brazilin on platelet-derived growth factor (PDGF)-BB induced VSMC proliferation and migration as well as the underlying mechanism of action. VSMC proliferation and migration were measured by Crystal Violet Staining, wound-healing and Boyden chamber assays, respectively. Cell cycle was analyzed by flow cytometry. Enzymatic action of matrix metalloproteinase-9 (MMP-9) was carried out by gelatin zymography. Expression of adhesion molecules, cell cycle regulatory proteins, the phosphorylated levels of PDGF receptor β (PDGF-Rβ), Src, extracellular signal regulated kinase (ERK) and Akt were tested by immunoblotting. The present study demonstrated that pretreatment with Brazilin dose-dependently inhibited PDGF-BB stimulated VSMC proliferation and migration, which were associated with a cell-cycle arrest at G0/G1 phase, a reduction in the adhesion molecule expression and MMP-9 activation in VSMCs. Furthermore, the increase in PDGF-Rβ, Src, ERK1/2 and Akt phosphorylation induced by PDGF-BB were suppressed by Brazilin. These findings indicate that Brazilin inhibits PDGF-BB induced VSMC proliferation and migration, and the inhibitory effects of Brazilin may be associated with the blockade of PDGF-Rβ - ERK1/2 and Akt signaling pathways. In conclusion, the present study implicates that Brazilin may be useful as an anti-proliferative agent for the treatment of vascular diseases.

Salvianolic acid A protects against vascular endothelial dysfunction in high-fat diet fed and streptozotocin-induced diabetic rats

Salvianolic acid A (SalA) is one of the main active ingredients of Salvia miltiorrhizae. The objective of this study was to evaluate the effect of SalA on the diabetic vascular endothelial dysfunction (VED). The rats were given a high-fat and high-sucrose diet for 1 month followed by intraperitoneal injection of streptozotocin (30 mg/kg). The diabetic rats were treated with SalA (1 mg/kg, 90% purity) orally for 10 weeks after modeling, and were given a high-fat diet. Contractile and relaxant responses of aorta rings as well as the serum indications were measured. Our results indicated that SalA treatment decreased the level of serum Von Willebrand factor and ameliorated acetylcholine-induced relaxation and KCl-induced contraction in aorta rings of the diabetic rats. SalA treatment also reduced the serum malondialdehyde, the content of aortic advanced glycation end products (AGEs), and the nitric oxide synthase (NOS) activity as well as the expression of endothelial NOS protein in the rat aorta. Exposure of EA.hy926 cells to AGEs decreased the cell viability and changed the cell morphology, whereas SalA had protective effect on AGEs-induced cellular vitality. Our data suggested that SalA could protect against vascular VED in diabetes, which might attribute to its suppressive effect on oxidative stress and AGEs-induced endothelial dysfunction.

Protection of salvianolic acid A on rat brain from ischemic damage via soluble epoxide hydrolase inhibition

Epoxyeicosatrienoic acids (EETs) and their regulating enzyme soluble epoxide hydrolase (sEH) have been associated with ischemic stroke. Salvianolic acid A (SAA) is proved to display potent cerebroprotection. However, little information is available about the link between them. This study aimed to investigate whether SAA exhibits its protective effects in rats subjected to middle cerebral artery occlusion (MCAO) through sEH and EETs. The results showed that SAA treatment ameliorated neurological deficits and reduced infarct volume. Notably, the beneficial effects of SAA were attenuated by co-administration of (14,15-epoxyeicosa-5(Z)-enoic acid (14,15-EEZE)), a putative selective EETs antagonist. Furthermore, SAA increased the 14,15-EET levels in the blood and brain of sham and MCAO rats. Assay for hydrolase activity showed that 1 and 3 mg/kg of SAA significantly diminished brain sEH activity of MCAO rats. A fluorescent assay in vitro indicated that SAA could inhibit recombinant human sEH activity in a concentration-dependent manner (IC50 = 1.62 μmol/l). Immunohistochemical analysis showed that SAA at the doses of 1 and 3 mg/kg significantly decreased sEH protein expression in hippocampus CA1 region of MCAO rats. In conclusion, cerebral protection of SAA is mediated, at least in part, via inhibiting sEH to increase EETs levels.

Salvianolic acid A protects human SH-SY5Y neuroblastoma cells against H2O2-induced injury by increasing stress tolerance ability

Salvianolic acid A (Sal A) is a polyphenol extracted from the root of the Salvia miltiorrhiza bunge. Hydrogen peroxide (H(2)O(2)) is a major reactive oxygen species (ROS), which has been implicated in stroke and other neurodegenerative diseases, including Alzheimers disease and Parkinsons disease. In this study, we investigated the neuroprotective effects of Sal A in human SH-SY5Y neuroblastoma cells against H(2)O(2)-induced injury. Our results showed that cells pretreated with Sal A exhibited enhanced neuronal survival and that this protection was associated with an increase in adenosine triphosphate (ATP) and the stabilization of mitochondrial membrane potential. In addition, Sal A markedly decreased the excessive activation AMP-activated protein kinase (AMPK) and the serine-threonine protein kinase, Akt, in SH-SY5Ycells induced by H(2)O(2). In conclusion, our results demonstrated that Sal A protects SH-SY5Y cells against H(2)O(2)-induced oxidative stress and these protective effects are related to stress tolerance and not energy depletion via inhibition of the AMPK and Akt signaling pathway.

A sensitive method for determination of salvianolic acid A in rat plasma using liquid chromatography/tandem mass spectrometry

Salvianolic acid A (SAA), a major effective constituent of Salvia miltiorrhizas, is widely used in traditional Chinese medicine. A sensitive rapid analytical method was established and validated for SAA in rat plasma, which was further applied to assess the pharmacokinetics of SAA in rats receiving a single oral dose of SAA. The method used liquid chromatography tandem mass spectrometry in multiple reaction monitoring mode with chloramphenicol as the internal standard. A simple liquid-liquid extraction based on ethyl acetate was employed. The combination of a simple sample cleanup and short chromatographic run time (3 min) increased the throughput of the method substantially. The method was validated over the range 1.4-1000 ng/mL with a correlation coefficient >0.99. The lower limit of quantification was 1.4 ng/mL for SAA in plasma. Intra- and inter-day accuracies for SAA were 95-113 and 98-107%, and the inter-day precision was less than 12%. This method is more sensitive and faster than previous methods. After a single oral dose of 100 mg/kg of SAA, the mean peak plasma concentration (Cmax) of SAA was 318 ng/mL at 0.5 h, the area under the plasma concentration-time curve (AUC0-12 h) was 698 +/- 129 ng.h/mL, and the elimination half-life (T1/2) was 3.29 h.

Vasorelaxant effect of formononetin in the rat thoracic aorta and its mechanisms

The purpose of the present study was to investigate the effect of formononetin and the related mechanisms on isolated rat thoracic aorta. Formononetin concentration dependently relaxed aortic rings precontracted with norepinephrine (NE, 1 μM) or KCl (80 mM). Pretreatment with formononetin noncompetitively inhibited contractile responses of aortas to NE and KCl. The vasorelaxant effect of formononetin partially relied on intact endothelia, which was significantly attenuated by incubation with Nω-nitro-l-arginine methyl ester (100 μM). In endothelium-denuded rings, glibenclamide (10 μM) and tetraethylammonium (5 mM) showed slight reduction in the vasorelaxant effect of formononetin. Moreover, formononetin reduced NE-induced transient contraction in Ca2+-free solution and inhibited the vasocontraction induced by increasing external calcium in medium plus 80 mM KCl. Our results suggested that formononetin induced relaxation in rat aortic rings through an endothelium-dependent manner via nitric oxide synthesis pathway, and also involving an endothelium-independent vasodilatation by the blockade of Ca2+ channels. The opening of K+ channels might also be one of the mechanisms of formononetin-induced vasorelaxation.