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Effects of genistein on the proliferation of cardiac fibroblasts

Zhan GAO ; Miaozhang ZHU ; Shisheng ZHOU ; Shunyan LU ; Haitao GUO ; Feng GAO ; Xinliang MA

Chinese Journal of Pharmacology and Toxicology.2001;15(2):159-160.

To study the effect of genistein on the proliferation of cardiac fibroblasts(CF), CFs were cultured from neonatal rat hearts, DNA synthesis of the cells was determined by incorporation of ［3H］TdR into DNA, the cell cycle was measured by flow cytometric analysis. Genistein(0.5－50 μmol*L-1) attenuated 2.5% fetal calf serum-induced proliferation of CF in concentration-dependent manner. Genistein(50 μmol*L-1) arrested CF cell progression at G2/M phase. The results suggest that genistein be a potential substance for treatment of cardiac fibrosis.

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18 α-Glycyrrhizic acid down-regulated the activities and mRNA expression of cytochrome P450 isoenzymes in rat hepatocyte sandwich cultures

Jing YANG ; Renxiu PENG ; Jieping YU

Chinese Journal of Pharmacology and Toxicology.2001;15(2):155-158.

To study the effect and mechanisms of 18 α-glycyrrhizic acid (18 α-GA) on cytochrome P450 (CYP) enzymes, the expression of CYP1A1, CYP2E1 and CYP3A was determined in rat hepatocyte sandwich cultures by using enzyme assay and semi-quantitative reverse transcriptase-polymerase chain reaction(RT-PCR). The results showed that the activities of CYP1A1 (7-ethoxyresorufin O-deethylase, EROD), CYP2E1(aniline hydroxylase, ANH) and CYP3A (erythromycin N-demethylase, ERD) were decreased in concentration-dependent manner after treatment with 18 α-GA(50－400 mg*L-1), and at the concentration of 200 mg*L-1 inhibitory rate reached the maximum (the maximum inhibitory rate was 59.6%, 69.7% and 44.7%, respectively). The time course revealed that the inhibition reached plateau level at d 4 of culure. 18 α-GA Decreased CYP1A1, CYP2E1 and CYP3A1 mRNA expression in dose-dependent manner, the maximum inhibitory rate was 44.5% , 58.1% and 37.1%, respectively. The results suggest that 18 α-GA down-regulate CYP expression at the transcriptive levels.

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Effect of 1-(2,6-dimethylphenoxy)-2-(3,4-dimethoxyphenylethyl-amino) propanehydrochloride on cystometry and benign prostatic hyperplasia in rats

Heng ZHENG ; Jiaqing QIAN ; Chunli SHAO ; Lin XIA ; Peizhou NI

Chinese Journal of Pharmacology and Toxicology.2001;15(2):150-154.

1-(2,6-Dimethylphenoxy)-2-(3,4-dimethoxyphenylethylamino) propane hydrochloride(DDPH) caused parallel rightward shifts of the phenylephrine(Phe) concentration-contractile response curves and did not suppress the maximal contractile response to Phe (pA2=7.24) in isolated rabbit urinary bladder smooth muscle. DDPH decreased the parameters of cystometry in urethane-anesthetized rats. Thirty minutes after DDPH (25 and 50 mg*kg-1 ig) administration, bladder capacity, voiding pressure, voiding threshold pressure were significantly decreased. With the observation of light-microscope and electron-microscope technique, DDPH (25 and 50 mg*kg-1*d-1 ig for 4 weeks) also inhibited the development of testosterone propionate-induced benign prostatic hyperplasia in rats. The results indicate that DDPH may inhibit benign prostatic hyperplasia and improve the urinary flow.

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Depressive effect on proliferation of vascular smooth muscle cells by tetrandrine in hypertensive rats

Qingping LI ; Zean LU ; Manren RAO

Chinese Journal of Pharmacology and Toxicology.2001;15(2):145-149.

To analyse the effect of tetrandrine(Tet) on proliferation of aortic vascular smooth muscle cells ( AVSMC), AVSMC were isolated and cultured from sham-operated rats(Sham), renovascular hypertensive rats〔RHR, 18 weeks after two kidney one clip(2K1C) operation〕, and Tet (50 mg*kg-1*d-1 po for 9 weeks from week 9 after 2K1C operation)treated RHR. The proliferation of AVSMC was detected by MTT method, and the DNA synthesis was evaluated by ［3H］-thymidine incorporation. The results showed that ①The ultrastructure of aorta suggested that AVSMC in RHR had transferred from contractile phenotype to synthetic phenotype; ②Compared to Sham, AVSMC from RHR showed a higher proliferative property with a higher cell number and an increased growth rate stimulated by norepinephrine(NE) or angiotensinⅡ(AngⅡ); ③Compared to untreated RHR, AVSMC from Tet treated RHR showed a reduced reactivity to NE- or AngⅡ-stimulated proliferation and growth rate; ④Tet(0.1－10 μmol*L-1) treated in vitro induced a concentration-dependent depression in ［3H］ thymidine-incorporation stimulated by NE or AngⅡ in AVSMC from either RHR or Sham. This study provides an evidence of increased reactivity to NE or AngⅡ in AVSMC of RHR. Tet inhibits the proliferation and DNA synthesis in AVSMC, depresses the susceptibility of AVSMC to AngⅡ and NE, both contribute to the regression effect on hypertensive vascular remodeling.

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Effects of preconditioning and praeruptorine C on intracellular free calcium level and NO content in hypertrophied vascular smooth muscle cells with hypoxia

Manren RAO ; Wanbing LIU ; Xiaowen ZHANG

Chinese Journal of Pharmacology and Toxicology.2001;15(2):141-144.

Effects of preconditioning(PC) and praeruptorine C(Pra-C) on intracellular free calcium level(［Ca2+］i) and NO content in hypertrophied vascular smooth muscle cells (VSMC) with hypoxia were studied. ①The aorta VSMC of rats with renovascular hypertension induced by two-kidney-one-clip(2K1C) were isolated and cultured. Fura-2/AM was as a calcium fluorescent indicator. It was seen that Pra-C(20 mg*kg-1*d-1，ig, for 9 weeks from week 9 after 2K1C) and PC (3 cycles of 5 min pure N2 and 5 min 95%O2+5%CO2) antagonisted the elevated activities(higher ［Ca2+］i) induced by KCl and norepinephrine in VSMC with hypo- xia (30 min pure N2). ② In hypertrophied VSMC stimulated by angiotensinⅡ, combination of Pra-C(10 μmol*L-1 for 24 h) and PC enhanced NO content to the normal level in hypertrophied VSMC with hypo- xia. The results suggest that combination of Pra-C and PC have cooperative protection for hypertrophied VSMC with hypoxia injury.

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Protective effects of 1-(2,6-dimethylphenoxy)-2-(3,4-dimethoxy-phenylethylamino) propane hydrochloride on brain ischemia and reperfusion injury in mice

Weiting WANG ; Lianjun GUO ; Ling QU ; Fang WANG ; Qing LU ; Jiaqing QIAN

Chinese Journal of Pharmacology and Toxicology.2001;15(2):137-140.

By using decapitating, intravenous injection of saturated MgCl2 and legation of bilateral carotid arteries with vagi, the effects of 1-(2,6-dimethylphenoxy)-2-(3,4-dimethoxyphenylethyl- amino) propane hydrochloride(DDPH) on survival time in mice were studied. With the model of cerebral ischemia for 20 min and reperfusion for 10 min, effects of DDPH on the superoxide dismutases(SOD) activity and malondialdehyde (MDA) content in brain tissue and pathological changes were studied. The results indicated that DDPH at dosages of 3,6,12,24 mg*kg-1 ip 30 min before ischemia prolonged the survival time significantly. Meanwhile, DDPH was found to increase the activity of SOD and reduce the content of MDA, as well as mitigate pathological damage of neuron after cerebral ischemia and reperfusion in mice. The results suggest that DDPH has protective effects on brain ischemia.

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Comparison of ATP and thrombin-induced Ca2+ entry in vascular endothelial cells

Wenli WEI ; Yongyuan GUAN ; Hua HE ; Guanlei WANG ; Hongmei RUAN ; Jiajun SUN

Chinese Journal of Pharmacology and Toxicology.2001;15(2):131-136.

The effects of drugs on intracellular calcium concentration(［Ca2+］i) were investigated with fura-2 fluorescence technique to investigate ATP and thrombin-induced Ca2+ entry in bovine aortic endothelial cells(BAEC). It was found that application of ATP and thrombin gave rise to biphasic ［Ca2+］i elevation. ATP or thrombin only triggered a fraction of cyclopiazonic acid(CPA)-sensitive Ca2+ store, which was enough to activate Ca2+ entry. The Ca2+ release induced by thrombin resulted from the activation of phospholipase C(PLC), whereas the PLC-independent mechanism was involved in ATP-induced Ca2+ release. Nifedipine had no effect on ATP and thrombin- induced Ca2+ entry. SK&F 96365 and ginsenoside-2A inhibited both ATP and CPA-induced Ca2+ entry, however no effect of them on thrombin-induced Ca2+ entry was found. The inhibitory effects of SK&F 96365 and ginsenoside-2A on CPA-induced Ca2+ entry were less than that on ATP-induced Ca2+ entry. The Ca2+ influx sensitive to SK&F 96365 was not the same as that to ginsenoside-2A. These observations suggest that both ATP and thrombin evoke Ca2+ release and Ca2+ influx by activation of different receptor. However their mechanisms appear different.

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Effects of tetrandrine on hydroxyproline content and myosin ATPase activity of hypertrophied myocardium in renovascular hypertensive rats

Zean LU ; Qingping LI ; Manren RAO ; Xiyong YU ; Shuguang LIN

Chinese Journal of Pharmacology and Toxicology.2001;15(2):121-124.

To study the effects of tetrandrine (Tet) on hypertrophied myocardial hydroxyproline content and myosin ATPase activity, left ventricular hypertrophy(LVH) was induced by renovascular hypertension (two-kidney, one-clip) in rats. Eight weeks after operation Tet 50 mg*kg-1*d-1 and enalapril(Ena) 6 mg*kg-1*d-1 were given by gavage for 8 weeks. The results showed that hydroxyproline content in LVH group was much higher than that of sham-operated one 〔(5.9±0.3) vs (3.6±0.4) mg*g-1 dry weight〕, and was decreased by 28.2% and 39.0% in Tet and Ena groups, respectively. Myosin ATPase activity in LVH group was much lower than that of sham-operated group 〔(0.43±0.09) vs (0.97±0.06) mmol Pi*min-1*g-1 protein, P<0.01〕. In Tet and Ena groups they were 60.5% and 118.6% higher than that of LVH group, respectively. The results suggest that Tet or Ena partially reduce the hydroxyproline content and elevate myosin ATPase activity of hypertrophied myocardium in renovascular hypertensive rats.

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Effect of daurisoline on monophasic action potential of rabbit hearts in vivo

Zhen LI ; Xianming LIN ; Jingsheng XIA ; Xiaoyan YANG ; Peili GONG ; Fandian ZENG

Chinese Journal of Pharmacology and Toxicology.2001;15(2):116-120.

The use-dependent characteristics of daurisoline on monophasic action potentials (MAP) of the left ventricle of the rabbit heart in situ were recorded with MAP recording technique. The results showed that daurisoline decreased monophasic action potential amplitude (MAPA) and prolonged monophasic action potential duration at the 50% and 90% (MAPD50, MAPD90), effective refractory period (ERP), ERP/MAPD90 at the steady-state cycle lengths of 240, 210, 180 ms. The percent of prolongation of MAPD50 was 12.8±2.9, 9.5±2.6, 9.0±1.6, that of MAPD90 was 10.9±2.6, 7.5±2.4, 6.5±2.7, that of ERP was 25.7±4.3, 18.5±4.1, 24.2±7.2, and that of ERP/MAPD90 was 13.7±4.5, 10.2±2.2, 16.1±5.1, respectively. Its effect showed no relation to frequency (n=6, P>0.05). The effects of sotalol on MAP were similar to that of daurisoline, but it prolonged MAPD90 and ERP in a reverse use-dependent manner (P<0.05). It is concluded that daurisoline has no use-dependent effects on MAP of rabbit hearts.

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Angiotensin-(1-7) dilates guinea-pig coronary arteries via nitric oxide

Yuan ZHOU ; Hanwu DENG ; Yuanjian LI

Chinese Journal of Pharmacology and Toxicology.2001;15(2):111-115.

The objective of the present study was to examine the effect of angiotensin-(1-7) 〔Ang-(1-7)〕 on coronary flow and cardiac function in isolated guinea-pig hearts. The isolated guinea-pig heart was perfused in a Langendorff mode. Coronary flow, heart rate, left ventricular pressure and its first derivatives (±dp/dtmax) were recorded. Results showed that Ang-(1-7) (100 or 300 nmol*L-1) caused an increase in coronary flow and an impairment in cardiac function in isolated guinea-pig hearts. Indomethacin, a cyclooxygenase inhibitor, did not affect the effect of Ang-(1-7). However, the increased coronary flow by Ang-(1-7) was abolished by pretreatment of Nω-nitro-L-arginine-methyl-ester, a nitric oxide(NO) synthase inhibitor. These results suggest that Ang-(1-7) increases coronary flow and reduces cardiac function, and that the vasodilating action is related to stimulation of NO release.

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