双龙方配伍配比对大鼠急性心肌缺血模型的影响

目的:验证中药双龙方配伍的合理性和科学性.方法:通过盐酸异丙肾上腺素造成大鼠的急性心肌缺血模型,从生理层面(心电图)、病理层面(心肌梗死面积)和细胞分子层面(细胞酶学指标CK,LDH,SOD,MDA含量变化),观察单方以及双龙方不同配比预防给药对心肌缺血的拮抗作用.结果:各给药组均能改善心电图缺血指标、降低血清中CK,LDH,SOD,MDA含量及减少心肌梗死面积,但双龙方配伍高剂量组比其他组具有更好的效果,其中以3:7高剂量组效果最优.结论:药效学筛选结果表明,按照双龙方配比3:7高剂量对防治大鼠急性心肌梗死效果最优.     

Isoproterenol-induced FKBP12.6/12 downregulation is modulated by ETA and ETB receptors and reversed by argirhein, a derivative of rhein

Aim:

To investigate which endothelin receptors mediated isoproterenol (ISO)-induced downregulation of FKBP12.6/12 in cardiomyocytes and study whether argirhein, a novel compound containing rhein and L-arginine that has anti-inflammatory activity, could reverse the downregulation of FKBP12.6/12 induced by ISO.

Methods:

Neonatal rat cardiomyocytes were incubated with ISO to downregulate FKBP12.6/12. Then the cells were treated with a selective ET_A blocker (PD156707) and a ET_B blocker (IRL1038), a dual ET_A/ET_B antagonist (CPU0213), and argirhein, respectively. FKBP12.6/12 expression was assayed by RT-PCR, Western blot, and immunocytochemistry.

Results:

The expression of FKBP12.6 mRNA was reduced by 37.7% (P<0.01) and 28.9% (P<0.05) relative to the control by ISO 1 and 0.1 μmol/L, respectively, but no response to ISO 0.01 μmol/L was observed in vitro. FKBP12.6/12 protein expression was reduced by 47.2% (P<0.01) and 37.8% (P<0.05) by ISO 1 and 0.1 μmol/L, respectively. This decrease was reversed significantly by PD156707, or IRL1038, and CPU0213. CPU0213 was more potent than either PD156707 or IRL-1038. Argirhein 10 μmol/L blunted the downregulation of FKBP12.6/12 by ISO, as demonstrated by the rising mRNA and protein levels and by the fluorescent density of the ISO-incubated cardiomyocytes.

Conclusion:

In cardiomyocytes, the ISO induced downregulation of FKBP12.6/12 is modulated by both ET_A and ET_B. A new compound, argirein, reversed the down-regulation of FKBP12.6/12 expression in myocardial cells stimulated with ISO.     

Ablation of p21-activated kinase-1 in mice promotes isoproterenol-induced cardiac hypertrophy in association with activation of Erk1/2 and inhibition of protein phosphatase 2A

Earlier investigations in our lab indicated an anti-adrenergic effect induced by activation of p21-activated kinase (Pak-1) and protein phosphatase 2A (PP2A). Our objective was to test the hypothesis that Pak-1/PP2A is a signaling cascade controlling stress-induced cardiac growth. We determined the effects of ablation of the Pak-1 gene on the response of the myocardium to chronic stress of isoproterenol (ISO) administration. Wild-type (WT) and Pak-1-knockout (Pak-1-KO) mice were randomized into six groups to receive either ISO, saline (CTRL), or ISO and FR180204, a selective inhibitor of Erk1/2. Echocardiography revealed that hearts of the Pak-1-KO/ISO group had increased LV fractional shortening, reduced LV chamber volume in diastole and systole, increased cardiac hypertrophy, and enhanced transmitral early filling deceleration time, compared to all other groups. The changes were associated with an increase in relative Erk1/2 activation in Pak-1-KO/ISO mice versus all other groups. ISO-induced cardiac hypertrophy and Erk1/2 activation in Pak-1-KO/ISO were attenuated when the selective Erk1/2 inhibitor FR180204 was administered. Immunoprecipitation showed an association between Pak-1, PP2A, and Erk1/2. Cardiac myocytes infected with an adenoviral vector expressing constitutively active Pak-1 showed a repression of Erk1/2 activation. p38 MAPK phosphorylation was decreased in Pak-1-KO/ISO and Pak-1-KO/CTRL mice compared to WT. Levels of phosphorylated PP2A were increased in ISO-treated Pak-1-KO mice, indicating reduced phosphatase activity. Maximum Ca²⁺-activated tension in detergent-extracted bundles of papillary fibers from ISO-treated Pak-1-KO mice was higher than in all other groups. Analysis of cTnI phosphorylation indicated that compared to WT, ISO-induced phosphorylation of cTnI was blunted in Pak-1-KO mice. Active Pak-1 is a natural inhibitor of Erk1/2 and a novel anti-hypertrophic signaling molecule upstream of PP2A.     

不同中医治法对异丙肾上腺素致大鼠心肌肥大的比较研究

目的观察不同中医治法对异丙肾上腺素致大鼠心肌肥大的干预作用。方法以异丙肾上腺素20 mg/kg1、0 mg/kg、5mg/kg递减皮下注射,3 mg/kg维持7 d制备大鼠心肌肥大模型,给予金匮肾气丸、真武汤、补阳还五汤及生脉饮5周,观察大鼠血流动力学指标、心输出量、心脏指数、左心室指数以及血清心房利钠肽(ANP)、脑钠肽(BNP)、血管紧张素Ⅱ(AngⅡ)及去甲肾上腺素(NE)含量的变化。结果异丙肾上腺素造模5周后,模型组大鼠血流动力学处于代偿状态,与正常组比较差异无统计学意义(P>0.05);但心输出量明显降低,血清ANP、BNP含量显著升高,心脏指数及左心室指数增加(P<0.05)。与模型组比较,补阳还五汤组及金匮肾气丸组能够有效提高心输出量,降低血清ANP、BNP水平,降低心脏指数(P<0.05)。生脉饮组和真武汤组能够降低血清ANP含量,对于模型大鼠心脏指数及血清BNP含量均无明显作用(P>0.05),但是有降低心输出量及心肌收缩功能的作用。结论益气活血法和温补肾阳法能够有效改善异丙肾上腺素致大鼠心肌肥大的血流动力学状况,改善过度激活的神经体液水平。     

Beta-adrenergic receptor activation induces long-lasting potentiation in burst-spiking but not regular-spiking cells at CA1-subiculum synapses

The hippocampus plays a central role in memory formation in the mammalian brain. The subiculum is the principal target of CA1 pyramidal cells and thus serves as the major relay station for the outgoing hippocampal information. Pyramidal cells in the subiculum have been classified as burst-spiking (BS) and regular-spiking (RS) cells. In this study we demonstrate that application of the β-adrenergic agonist isoproterenol (2 μM) induces a chemical form of long-term potentiation (LTP) of responses to alvear stimulation in (BS) but not in (RS) cells. This effect is prevented by the β-adrenergic receptor antagonist propranolol (2 μM). The isoproterenol-induced LTP in (BS) cells does not depend on postsynaptic Ca²⁺-signaling, as 1,2-bis(2-aminophenoxy)ethane-N,N,N′,N′-tetraacetic acid (BAPTA) does not prevent its induction. Furthermore, paired-pulse facilitation (PPF) and coefficient of variation (CV) analysis indicate the site of the LTP expression to be presynaptic. Our findings show that activation of β-adrenergic receptors (β-ARs) at CA1-subiculum synapses induces a cell-type-specific form of chemical LTP in subicular (BS) cells that may allow a target-specific trafficking of hippocampal output.     

Role of NO in the systemic hemodynamic response to β2-adrenoceptor stimulation

Blockade of NO synthesis in most narcotized rats was followed by an increase in depressor effects (by 45%) and decrease in total peripheral resistance (by 63%) upon treatment with isopropyl norepinephrine (isoproterenol). Our results indicate that NO secretion in the endothelium modulates the systemic hemodynamic response to β₂-adrenoceptor stimulation. __________ Translated from Byulleten’ Eksperimental’noi Biologii i Meditsiny, Vol. 142, No. 8, pp. 128–131, August, 2006     

Cardioprotective effect of water and ethanol extract of Salvia miltiorrhiza in an experimental model of myocardial infarction

Ethnopharmacological relevance

Salvia miltiorrhiza has long been used in the traditional Chinese formulations for the treatment of heart ischemic diseases.

Aim of the study

We investigated the cardioprotective effect of purified Salvia miltiorrhiza extract (SME) in an experimental model of acute myocardial infarction.

Materials and methods

Following induction of acute myocardial infarction in rats by adminstration of isoproterenol, hemodynamic and electrocardiographic parameters were monitored and recorded continuously, cardiac enzymes and parameters of oxidative stress were measured, and histopathological examination of heart tissue was performed. Experiments were performed in rats treated with SME or vehicle, as well as in those treated with Fufang Danshen Tablet (FDT) as a positive control which has previously been shown to prevent myocardial ischemia.

Results

Isoproterenol-treated rats showed reductions in left ventricular systolic pressure as well as in maximum and minimum rate of developed left ventricular pressure, together with an increase in left ventricular end-diastolic pressure. They also demonstrated ST-segment elevation, together with increases in serum levels of lactate dehydrogenase, glutamic oxalacetic transaminase, creatine kinase and malondialdehyde, as well as decreases in serum activities of glutathione peroxidase and superoxide dismutase. Oral administration of SME (29.76 or 59.52 mg/kg) blunted all of the hemodynamic and biochemical changes induced by isoproterenol, as did FDT (1210 mg/kg). The protective effect of SME on isoproterenol-induced myocardial damage was further confirmed by histopathological examination.

Conclusions

Our results suggest that SME affords protection against isoproterenol-induced myocardial infarction.     

金匮肾气丸对异丙肾上腺素致心室重构大鼠神经体液因子的调节

目的:研究金匮肾气丸对异丙肾上腺素致大鼠心室重构相关神经体液因子和形态学的改变.方法:异丙肾上腺素连续3 d以20,10,5 mg· kg-1递减皮下注射,3 mg· kg-1维持7d制备大鼠心室重构模型,造模成功后分别用依那普利(2 mg·kg-1),金匮肾气丸(7.5 g·kg-1)ig给药5周及15周,从血浆中神经内分泌因子和形态学进行疗效比较研究.结果:血浆中神经内分泌因子的检测:5,15周时模型组血浆中心房钠尿肽(ANP)含量均高于正常组;5周时与模型组比较,金匮肾气丸组的ANP含量均较低(P＜0.05);15周时,金匮肾气丸组的ANP、脑尿钠肽(BNP)含量均降低(P＜0.05).5周模型组的血清去甲肾上腺素(NE)浓度高于正常组,但无显著性差异,15周模型组的NE显著高于正常组(P＜0.05);5,15周时,依那普利组和金匮肾气丸组的NE与模型组比较均无显著性差异.5,15周,模型组的血清血管紧张素Ⅱ(AngⅡ)浓度与正常组比较均无显著性差异.心肌病理形态学观测结果:5周时,模型组有较多成纤维细胞和新生毛细血管,肉芽组织较明显,15周时,模型组呈现广泛纤维化,形成疤痕组织;5,15周时,金匮肾气丸组的心肌细胞均有一定程度的病理变化,但较模型组而言均有改善.结论:金匮肾气丸能够改善异丙肾上腺素致大鼠心室重构过度激活的神经体液水平,但这种改善作用在晚期时较为明显.     

Dietary Phenolic Acids of Macrotyloma uniflorum (Horse Gram) Protect the Rat Heart Against Isoproterenol‐Induced Myocardial Infarction

The present study investigates the cardioprotective activity of the Macrotyloma uniflorum seed extract (MUSE) and its phenolic acids (p‐coumaric acid and ferulic acid) in isoproterenol (ISO)‐induced myocardial infarction in rats. The previously mentioned phenolic acids were isolated and quantified from MUSE by HPLC. Pretreatment of gemfibrozil (reference standard), MUSE (250 and 500 mg/kg) and the phenolic acids for 30 days to rats treated with ISO (85 mg/kg) on the last 2 days resulted in a significant attenuation of the ISO‐elevated levels of serum marker enzymes (aspartate aminotransferase, lactate dehydrogenase and creatine phosphokinase MB), total cholesterol, triglycerides, uric acid, C‐reactive protein and malondialdehyde and a restoration of the levels of the ISO‐depleted marker enzymes, reduced glutathione and the antioxidant enzymes—superoxide dismutase, catalase, glutathione peroxidase and glutathione reductase in heart. Restoration of the ISO‐altered electrocardiogram pattern and haemodynamic parameters (left ventricular end diastolic pressure, heart rate, systolic, diastolic and mean arterial pressure) was also brought about by treatment with MUSE and the phenolic acids. It may be concluded that MUSE treatment to ISO‐challenged rats exhibits a significant cardioprotective effect probably because of the potent antioxidant activity of its phenolic acids that salvage the myocardium from the deleterious effects of ISO. Copyright © 2016 John Wiley & Sons, Ltd.     

Altered β-adrenergic response in mice lacking myotonic dystrophy protein kinase

The protein kinase product of the gene mutated in myotonic dystrophy 1 (DMPK) is reported to play a role in cardiac pathophysiology. To gain insight into the molecular mechanisms modulated by DMPK, we characterize the impact of DMPK ablation in the context of cardiac β-adrenergic function. Our data demonstrate that DMPK knockout mice present altered β-agonist-induced responses and suggest that this is due, at least in part, to a reduced density of β(1)-adrenergic receptors in cardiac plasma membranes.