Protective effects of scutellarin and breviscapine on brain and heart ischemia in rats

Scutellarin is an active molecule existing in Erigeron breviscapus (vant.) Hand-Mazz. The present work was designed to study the antiischemic effects of scutellarin and its mixture with another substance, breviscapine, in male Sprague-Dawley (SD) rats. Ligature of left anterior descending arteries was performed to induce acute myocardial infarction (MI), and the middle cerebral artery occlusion was created to induce focal cerebral ischemia. The MI size was significantly reduced by scutellarin (15 and 50 mg/kg) but not by breviscapine (5 to 50 mg/kg); the effect of scutellarin on the anti-MI was dose-dependent. Compared with control group, scutellarin (50 mg/kg) reduced the myocardium cell apoptosis in MI rats. The two drugs together (5 to 50 mg/kg) significantly reduced infarction size in focal brain ischemic rats (P < 0.05). There were no significant differences among the 3 dosages in breviscapine-treated rats, and the effect of scutellarin on the anticerebral ischemia was dose-dependent. The results demonstrate that the protective effects of scutellarin on cardiovascular and cerebrovascular ischemia were better than its mixture, breviscapine, in rats.     

Protective effects of ACE inhibitors on vascular endothelial dysfunction induced by exogenous advanced oxidation protein products in rats

To explore detrimental effects of advanced oxidation protein products-bovine serum albumin (BSA) on endothelial function and compare the favorable effects of angiotensin-converting enzyme (ACE) inhibitors: captopril and enalapril. Male Sprague-Dawley rats were randomly divided into groups: control, advanced oxidation protein products-BSA, captopril (10, 20 mg/kg/day), enalapril (15 mg/kg/day), and N(G)-nitro-l-arginine methyl ester (l-NAME, 300 mg/kg/day) plus captopril (20 mg/kg/day) groups. All animals were given advanced oxidation protein products-BSA (100 mg/kg/day, i.v.) except for control group (iv. equal volume of PBS). Rats in other groups were received different drugs intragastrically after advanced oxidation protein products-BSA administration. Endothelium-dependent relaxation of thoracic aorta was assayed. Content of nitrite/nitrate (NO), malondialdehyde (MDA), activities of glutathione peroxidase (GSH-Px), superoxide dismutase (SOD) and of ACE in Sera, as well as renal function index including blood urea nitrogen and creatinine were measured. After 30 days, the endothelium-dependent relaxation of blood vessels in received advanced oxidation protein products-BSA rats was significantly impaired compared with control rats. The impairment was accompanied by decreases of serum NO, activity of GSH-Px and SOD. Administration of captopril and enalapril not only decreased damage of endothelium-dependent relaxation, but also reverse the changes of MDA levels, NO content and activity of SOD. The protective effect of captopril was abolished by L-NAME. Blood urea nitrogen and creatinine had no significant differences between various groups. ACE activities were decreased in high captopril and enalapril groups, but did not significantly change in other groups. The results suggested that captopril and enalapril have similar effects on endothelial dysfunction induced by advanced oxidation protein products-BSA, which indicated that protective effects of captopril are not related to sulfhydryl group.     

Protective effects of quercetin against phenylhydrazine-induced vascular dysfunction and oxidative stress in rats.

Oxidative stress is a major contributor to the development of vascular dysfunction found in various pathological conditions. Quercetin, one of the potent antioxidant bioflavonoid compounds, has been shown to alleviate oxidative injury by modulation of gene expression leading to suppression of production of reactive oxygen and nitrogen species and conferring an antiapoptotic activity. The aim of the present study was to investigate the protective effects of quercetin in a model of phenylhydrazine (PHZ)-induced oxidant stress, vascular dysfunction and hemodynamic disturbance in rats. Male Sprague-Dawley rats were administered quercetin orally (25 or 50mg/kg/day) for 6 days. On day four, all animals except those in the normal control group, were administered PHZ intraperitoneally. The results showed that PHZ induced severe hemolysis. The mean arterial pressure and hindlimb vascular resistance of PHZ-control rats were markedly decreased compared to normal controls. Treatment with quercetin significantly improved arterial blood pressure and peripheral vascular resistance. Vascular responsiveness to bradykinin, acetylcholine, and phenylephrine in PHZ-control rats was dramatically suppressed and quercetin restored these responses in a dose-dependent manner. Quercetin partially protected blood glutathione, suppressed plasma malondialdehyde levels, and largely suppressed nitric oxide metabolites and superoxide anion production. These results provide the first evidence for the role of the flavonoid, quercetin, in the alleviation of vascular dysfunction in an animal model of PHZ-induced oxidant stress.     

L-精氨酸对糖尿病患者血管内皮功能的保护作用

目的研究L-精氨酸对糖尿病引起的血管内皮功能损伤的保护作用和意义。方法将60例糖尿病患者随机分为安慰剂对照组（n=30）和L-精氨酸治疗组（n=30）。L-精氨酸对照组给予口服精氨酸7g每天。两组治疗28d后再过7d的药物洗脱期。在治疗前和治疗后测定两组患者血浆一氧化氮（NO）、内皮素（ET）、血管性血友病因子（vWF）浓度及检测肱动脉血流介导的扩张反应（FMD）,并进行分析。结果L精氨酸治疗组较安慰剂对照组,血浆NO浓度升高,vWF和ET水平下降,差异有统计学意义（P〈0．05）。同时L精氨酸治疗的FMD较对照组明显升高（P〈0．05）。结论L-精氨酸可影响血管内皮活性物质,影响血管内皮的收缩舒张作用,从而对高血糖伴随的血管损伤有保护作用。     

丁基苯酞对血管性痴呆大鼠的保护作用

目的 研究丁基苯酞(butylphthalide,DBT)对血管性痴呆大鼠学习记忆、核因子-κB(nuclear factor-κB,NF-κB)及环氧合酶-2(cyclooxygenase-2.COX-2)的影响,探讨DBT对血管性痴呆的干预疗效.方法 大鼠随机分为假手术组(SOG)、模型组(MG)、丁基苯酞大剂量治疗组(DBT1)、丁基苯酞小剂量治疗组(DBT2)、丁基苯酞预防组(DBT3),用药1月,采用HE染色,观察海马CA1区锥体细胞的改变,免疫组化方法检测海马CA1区NF-κBp65、COX-2蛋白的表达.结果 与模型组比较,DBT不同剂量治疗1月后,学习记忆能力改善,海马CA1区神经元变性、坏死不同程度减轻;NF-κBp65、COX-2阳性细胞数表达减少(P<0.01),且不同剂量组间亦有差异(P<0.01).结论 丁基苯酞改善实验大鼠的学习记忆能力,减少实验大鼠海马CA1区神经细胞的丢失,降低血管性痴呆大鼠海马CA1区NF-κB、COX-2表达,可能具有预防和治疗血管性痴呆的作用.     

Protective effects of breviscapine on ischemic vascular dementia in rats

Breviscapine, a traditional Chinese medicine, is extensively used in clinic to treat cardiovascular diseases and cerebrovascular injury. In this study, we demonstrated the effects of breviscapine on vascular dementia (VD) rats, which were mimicked by permanent occlusion of bilateral common carotid arteries. Breviscapine (2 mg/kg for 14 d) improved the performance of learning and memory of VD rats in Morris water maze, decreased the level of lipid peroxidation and free radicals, and attenuated the pathological alterations, such as nuclear shrink, cellular edema and irregular arrangement of pyramidal layer in the hippocampal CA(1) area. In vitro experiment, breviscapine (50 microg/l) protected cortical neuron from injury and decreased intracellular calcium overloading induced by H2O2 (10 mM). The results suggest that breviscapine has therapeutic effect on cerebral ischemia and vascular dementia.     

灯盏花乙素对超氧阴离子引起的大鼠脑突触体氧化应激的保护作用

目的：研究灯盏花乙素对超氧阴离子引起的大鼠脑突触体氧化应激的保护作用．方法：采用与黄嘌呤(0．3mmol／L)和黄嘌呤氧化酶(0．02U)体系在37℃下孵育30min,建立大鼠脑突触体超氧阴离子氧化损伤模型．通过测定脂质过氧化产物丙二醛评价脂质过氧化程度．通过脂溶性荧光探针DPH的各向异性判断突触体膜的流动性．胞内钙离子的测定采用荧光光度法,以Fura2-AM为荧光探针．测定ATP酶解释放的无机磷确定Na~ ／K~ -ATP酶的活性．结果：超氧阴离子使大鼠脑突触体的脂质过氧化产物丙二醛及胞内钙离子浓度显著上升,突触体的膜流动性和Na~ ／K~ -ATP酶的活性则显著下降,预先加入灯盏花乙素(25-100μmol／L)则能显著缓解超氧阴离子引起的氧化性损伤,表现为丙二醛的水平和胞内钙离子浓度下降,膜流动性增加及Na~ ／K~ -ATP酶活性的恢复．结论：灯盏花乙素对超氧阴离子引起的大鼠脑突触体氧化应激具有良好的保护作用．     

如意珍宝片对血管性痴呆模型大鼠的保护作用

目的 研究如意珍宝片对血管性痴呆(VD)大鼠的保护作用。方法 采用改良双侧颈总动脉永久性结扎法制备大鼠VD模型,以Y迷宫为学习记忆评价指标,并测定VD大鼠脑内多巴胺(DA)、去甲肾上腺素(NE)、5-羟色胺(5-HT)3种单胺类神经递质水平。结果 如意珍宝片能显著的增加Y迷宫的正确次数和提高脑内3种单胺类神经递质水平。结论 如意珍宝片能提高VD大鼠学习记忆能力,升高脑内单胺类神经递质水平,从而改善大脑皮层的兴奋性,激活脑损伤后的学习记忆过程。     

Protective effects of Astragalus polysaccharides against endothelial dysfunction in hypertrophic rats induced by isoproterenol

Astragalus polysaccharide (APS) is an important bioactive component extracted from Chinese herb Astragalus membranaceus. It has been widely used in treatment of cardiovascular diseases. We have previously reported that APS could inhibit isoproterenol-induced cardiac hypertrophy. The present study was designed to evaluate the protective effect of APS on vascular endothelia in cardiac hypertrophy rats induced by isoproterenol (ISO). ISO (10 mg × kg^− 1) was intraperitoneally injected once daily for 2 weeks to induce cardiac hypertrophy. APS (400 and 800 mg × kg^− 1) was intragastrically injected once daily along with ISO. The results showed that combination with APS significantly ameliorates the endothelial dysfunction while attenuates cardiac hypertrophy induced by ISO. We found that administration with APS could attenuate the increase in number of circulating endothelial cell (CEC). APS also decreases the superoxide anion generation and the protein expression of p65 and the levels of TNF-α and IL-6; while increases the cGMP levels, an activity marker for nitric oxide (NO) in aortas. In addition, APS improves the relaxation dysfunction in isolated aortic rings and increases the protein expression of IκBα and Cu/Zn-SOD in aortas. In conclusion, our results suggested that APS had a protective effect against endothelial dysfunction in hypertrophic rats induced by ISO. The underlining mechanisms may be contributed to the anti-inflammatory effects and the improvement of the imbalance between reactive oxygen species (ROS) and NO.     

Protective effects of sinapic acid on lysosomal dysfunction in isoproterenol induced myocardial infarcted rats

In the pathology of myocardial infarction, lysosomal lipid peroxidation and resulting enzyme release play an important role. We evaluated the protective effects of sinapic acid on lysosomal dysfunction in isoproterenol induced myocardial infarcted rats. Male Wistar rats were treated with sinapic acid (12 mg/kg body weight) orally daily for 10 days and isoproterenol (100 mg/kg body weight) was injected twice at an interval of 24 h (9th and 10th day). Then, lysosomal lipid peroxidation, lysosomal enzymes in serum, heart homogenate, lysosomal fraction and myocardial infarct size were measured. Isoproterenol induced myocardial infarcted rats showed a significant increase in serum creatine kinase-MB and lysosomal lipid peroxidation. The activities of β-glucuronidase, β-galactosidase, cathepsin-B and D were significantly increased in serum, heart and the activities of β-glucuronidase and cathepsin-D were significantly decreased in lysosomal fraction of myocardial infarcted rats. Pre-and-co-treatment with sinapic acid normalized all the biochemical parameters and reduced myocardial infarct size in myocardial infarcted rats. In vitro studies confirmed the free radical scavenging effects of sinapic acid. The possible mechanisms for the observed effects are attributed to sinapic acid’s free radical scavenging and membrane stabilizing properties. Thus, sinapic acid has protective effects on lysosomal dysfunction in isoproterenol induced myocardial infarcted rats.     

Protective effects of luteolin-7-glucoside against liver injury caused by carbon tetrachloride in rats

Ixeris chinensis (Thunb.) Nakai has been used as a Chinese folk medicine; the information on the physiological and biochemical functions of the compounds extracted from I. chinensis is still scanty. We investigated the effects of luteolin -7-glucoside (LUTG) isolated from I. chinensis against liver injury caused by carbon tetrachloride (CCl4). CCl4 significantly increased the enzyme activities of glutamic pyruvic transaminase (GPT) and glutamic oxaloacetic transaminase (GOT) in blood serum, as well as the level of malondialdehyde (MDA) and 8-hydroxydeoxyguanosine (8-OHdG) in liver tissue, and decreased the levels of reduced glutathione (GSH). Pretreatment with LUTG was not only able to suppress the elevation of GPT, GOT, MDA and 8-OHdG, and inhibit the reduction of GSH in a dose-dependent manner in vivo, but also reduce the damage of hepatocytes in vitro. On the other hand, we also found LUTG has strong antioxidant activity against reactive oxygen species (ROS) in vitro in a concentration-dependent manner. The hepatoprotective activity of LUTG was possibly due to its antioxidant properties, acting as scavengers of ROS. These results obtained in vivo and in vitro suggest that LUTG had protective effects against hepatic oxidative injury induced by chemicals. Further studies on the pharmaceutical functions and immunological responses of LUTG may help in the development of a clinical application.     

Protective effects of nebivolol and reversal of endothelial dysfunction in diabetes associated with hypertension

This study aims to decipher the potential effects of nebivolol in prevention and/or regression of renal artery dysfunction in diabetes associated with hypertension. Renal arteries were isolated from 80 male mice divided into four experimental groups: (i) group D: diabetics, at 2 months since streptozotocin injection; (ii) group Din: mice that at the initiation of streptozotocin diabetes were treated with 10 mg/kg b.w./day nebivolol for 2 months, to test for the potential prevention of vascular dysfunction; (iii) group Dfin: mice that after 2 months of diabetes were treated daily with 10 mg/kg b.w./day nebivolol for additional 2 months, in order to follow the possible regression of the dysfunction, and (iv) controls (C), age-matched healthy animals. The following measurements were performed: arterial blood pressure, plasma glucose concentration, and the vascular reactivity of the renal arteries in response to noradrenaline (10(-4) M), acetylcholine (10(-4) M) and sodium nitroprusside (10(-4) M). To assess the molecular mechanisms involved in the reactivity of the renal artery, the contribution of mitogen-activated protein kinase (MAP kinase) pathway and of L-type voltage gated Ca(2+) channels (in the contractile response to noradrenaline), of nitric oxide (NO) and Ca(2+) activated K(+) channels (in the endothelium-dependent vasodilator response), and of cGMP (in the endothelium-independent vasodilator response) was examined by exposing the arteries to corresponding inhibitors, and by using myograph and patch-clamp techniques, immunoblotting and NO assays. Results showed that, group D was characterized by hyperglycemia (blood glucose concentration: 136.66 +/- 4.96 mg/dl, a value approximately 65% increased compared to group C) and hypertension (systolic blood pressure: 145.66 +/- 5.96 mm Hg, a value approximately 34% increased compared to group C). Compared to group D, group Din was characterized by diminished blood glucose concentration ( approximately 1.6 fold), reduced systolic and diastolic blood pressure ( approximately 1.3 fold) and heart rate ( approximately 1.6 fold), as well as by increased contractile response of the renal artery to noradrenaline ( approximately 1.84 fold) and of the impeded vasodilator response to acetylcholine ( approximately 1.81 fold) and sodium nitroprusside ( approximately 1.42 fold). Together, these effects demonstrate that administration of 10 mg/kg b.w./day nebivolol at the moment of diabetes induction has preventive effects, ameliorating diabetes dysfunctions. Compared to group D, group Dfin was characterized by diminished glucose concentration ( approximately 1.3 fold), reduced systolic and diastolic blood pressure and heart rate (both approximately 1.2 fold), and by augmentation of contractile response of the renal artery to noradrenaline ( approximately 1.62 fold) and of vasodilator response to acetylcholine ( approximately 1.13 fold) and sodium nitroprusside ( approximately 1.19 fold). These effects assess that administration of 10 mg/kg b.w./day nebivolol after 2 months of diabetes contributes to regression of diabetes-associated dysfunctionalies. Nebivolol influenced the molecular mechanisms involved in renal artery reactivity in diabetic and hypertensive mice: it increased the NO production and endothelial NO synthase (eNOS) protein expression, decreased the expression of proportional, variant protein in L-type calcium channels and Ca(2+) activated K(+) channels, and diminished the MAP kinase activity. The reported data suggest that nebivolol may offer additional vascular protection for treating diabetes associated with hypertension.     

高血压致认知功能障碍机制进展

随着社会、经济和医学的发展,人们的寿命得以延长,与老龄化相关的巨大挑战是脑血管病及认知功能损害两大疾病明显增多,给病人、家庭和社会带来负担。高血压是认知障碍的重要影响因素之一,高血压通过损害脑微循环的结构和功能完整性,破坏血脑屏障,引发神经炎症影响认知功能,以及长期高血压引起的脑小血管病包括白质高信号、腔隙性梗死和微出血,也会导致认知能力下降。目前多项研究表明适当的降压治疗在一定程度上能预防或延缓高血压病人的认知功能障碍。     

Protective effects of vasonatrin peptide against hypobaric hypoxia-induced pulmonary hypertension in rats

1. The aim of the present study was to investigate the in vivo effects of vasonatrin peptide (VNP) on hypoxia-induced pulmonary hypertension (HPH).
2. The HPH model was developed by subjecting rats to hypobaric hypoxia. The HPH rats were then treated with either VNP (50 μg/kg per day, i.p.) or saline (0.5 mL, i.p.) every day for 7 days. Haemodynamic indices, right ventricular hypertrophy (RVH) and remodelling of the pulmonary arteries were evaluated. In addition, plasma levels of atrial natriuretic peptide (ANP), endothelin (ET)-1 and angiotensin II (AngII) were determined, as was natriuretic peptide receptor-C (NPR-C) mRNA expression in the right ventricle.
3. Hypobaric hypoxia induced severe HPH compared with the normoxic control group. Treatment of HPH rats with VNP for 1 week significantly reduced mean pulmonary arterial pressure, pulmonary vascular resistance, RVH and muscularization of the pulmonary arteries, although pulmonary blood flow was increased in this group. In addition, significantly lower levels of plasma ET-1 and AngII and cardiac NPR-C mRNA expression were observed in VNP-treated compared with saline-treated HPH rats, whereas higher plasma concentrations of ANP were found in the former group. Acute intravenous administration of 50 μg/kg VNP significantly ameliorated pulmonary haemodynamics in HPH rats.
4. Taken together, the date indicate that VNP has certain preventative and therapeutic effects against HPH.     

Effects of ovariectomy on naloxone-modulated hypertension in spontaneously hypertensive rats (SHR)

Ovariectomy was performed at 4 weeks of age (W), and the rats were used when they were 33 and 75 W old. Systolic blood pressure (BP) was measured by the tail-cuff method. Naloxone (10 mg/kg) was given i.p. Catecholamines (CA) were determined with HPLC. Norepinephrine (NE) was not significantly altered in intact rats by naloxone; however, a significant increase in NE appeared in the plasma, hippocampus, thalamus plus mid-brain and hypothalamus in castrated rats following naloxone. With naloxone treatment, dopamine (DA) was significantly increased in the plasma and hypothalamus, but decreased in the cerebral cortex in intact rats; and with castrated rats, there was a tendency to see an increase in plasma DA and significantly increased levels of DA in the thalamus plus mid-brain and hypothalamus. This suggests that in female brain, lack of estrogen in the castrated rats leads to an increase in intrinsic opiate, and this in turn inhibits CA release. On the other hand, when naloxone was administered to castrated rats, intrinsic opiate was blocked, and, consequently, inhibition of CA release was lost and induction of CA release was enhanced.     

Protective effects of cariporide on endothelial dysfunction induced by high glucose

Aim: To explore the effects of cariporide, a selective sodium-hydrogen antiporter inhibitor, on endothelial dysfunction induced by high glucose. Methods: Acetylcholine (ACh)-induced endothelium-dependent relaxation (EDR), sodium nitroprusside (SNP)-induced endothelium-independent relaxation and biochemical parameters including malondialdehyde (MDA), superoxide dismutase (SOD), and nitric oxide (NO) were measured in rat isolated aorta. Results: A 6-h incubation of aortic rings with high glucose (44 mmol/L) resulted in a significant inhibition of EDR, but had no effects on endothelium-independent relaxation. After the 6-h incubation of aortic rings in the co-presence of cariporide (0.01, 0.1, and 1μmol/L) with high glucose, cariporide prevented the inhibition of EDR caused by high glucose in concentration-dependent manners. Similarly, high glucose decreased SOD activity and contents of NO, and increased MDA concentration in aortic tissue. Cariporide (1 μmol/L) significantly resisted the decrease of NO content and SOD activity, and elevation of MDA concentration caused by high glucose in aortic tissues. Mannitol (44 mmol/L) or cariporide (1μmol/L) alone had no effect on EDR, endothelium-independent relaxation and biochemical parameters. Conclusion: Cariporide significantly prevented endothelial dysfunction induced by high glucose. The mechanisms of endothelial dysfunction induced by high glucose may involve the activation of sodium-hydrogen antiporter and the generation of oxygen-free radicals, but it is not related to the change of osmolarity.     

Study on metabolism of scutellarin in rats by HPLC-MS and HPLC-NMR

Scutellarin is the major active constituent of Scutellaria barbata D. The metabolism of scutellarin has been investigated in rats. The solid-phase extraction and HPLC-DAD methods were established to separate and analyse metabolites. Five metabolites (M1–M5) were identified by enzymatic hydrolysis, HPLC-DAD, HPLC-MS and HPLC-NMR. M1 and M3 were conjugates of scutellarin with two sulfate groups, which have not been reported in natural plants. M2 was scutellarin; M4 was 6-methyl-scutellarin; and M5 was 6-methyl-scutellarein. The metabolic pathway was proposed.     

Study on metabolism of scutellarin in rats by HPLC-MS and HPLC-NMR

Scutellarin is the major active constituent of Scutellaria barbata D. The metabolism of scutellarin has been investigated in rats. The solid-phase extraction and HPLC-DAD methods were established to separate and analyse metabolites. Five metabolites (M1-M5) were identified by enzymatic hydrolysis, HPLC-DAD, HPLC-MS and HPLC-NMR. M1 and M3 were conjugates of scutellarin with two sulfate groups, which have not been reported in natural plants. M2 was scutellarin; M4 was 6-methyl-scutellarin; and M5 was 6-methyl-scutellarein. The metabolic pathway was proposed.     

山楂叶总黄酮对高脂血症大鼠血清SOD、MDA及PON1的影响

目的:探讨山楂叶总黄酮(hawthorn leaves flavonoids,HLF)对高脂血症大鼠抗氧化作用的影响及与PON1活性的关系。方法:采用维生素D3加脂肪乳剂造成大鼠高脂血症模型,并检测血清超氧化物歧化酶(SOD)、丙二醛(MDA)及对氧磷酶(PON1)含量。结果:1.HLF可明显降低血清总胆固醇(TC)、甘油三脂(TG)和低密度脂蛋白胆固醇(LDL-C)含量,提高高密度脂蛋白胆固醇(HDL-C)/TC比值。2.HLF可增强SOD及PON1活性,抑制高脂饮食所升高的MDA水平。结论:HLF具有较强的抗氧化作用,其抗AS作用可能与其增加PON1表达、继而增强HDL抗氧化能力有关。