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Objective To determinate the effects of sodium tanshinone ⅡA sulfonate(STS)on cardiomyocyte hypertrophy and explore the relative effects of STS on mitogen-activated protein kinase signal transduction system in rats with cardiomyocyte hypertrophy through constricting the thoracic aorta.Methods The models of cardiomyocyte hypertrophy were established in vivo,and the thoracic aorta was partially tied between the right innominate and the left common carotid arteries.The rats were randomly divided into 6 groups(n=8/group)as follows:①sham,②transverse aortic constriction(TAC),③TAC+low-dose Tan(TAC+LT)(5 mg/kg),④TAC+middle-dose Tan(TAC+MT)(10 mg/kg),⑤TAC+high-dose Tan(TAC+HT)(20 mg/kg),and ⑥ TAC+Val(10 mg/kg).After treatment for 8 weeks,echocardiography was performed to observe the changes in hypertrophy and heart function,and heart samples were cut into transverse sections and stained with hematoxylin and eosin(H&E).The MAPKs protein expression in the cardiomyocytes was detected by Western blot.Results The heart weight index(HWI),left ventricular mass index(LVMI)and cross-sectional diameter of cardiomyocytes(CD),left ventricular posterior wall thickness(LVWT),and interventricular septal thickness(IVS)were significantly increased in TAC group as compared with sham group.The relative parameters in STS groups and Val group were reduced as compared with those in TAC group.Western blot analysis revealed the p-ERK and p-p38 expression was significantly decreased in TAC group as compared with sham group(P＜0.01).The p-ERK expression was significantly decreased in STS groups and Val group as compared with TAC group(P＜0.05).The TAC+HT group,TAC+MT group and Val group had significantly higher p-p38 expression than TAC group(P＜0.05).Conclusion Tanshinone ⅡA could regulate the expression of protein in MAPK pathway to exert its inhibitory effects on hypertrophy of cardiomyocytes.
ABSTRACT
To investigate the molecular mechanism by which Tanshinone IIA (TSN IIA) prevents left ventricular hypertrophy (LVH), we examined the expression of AT1R, TGF-beta1 and Smads gene in the hypertrophic myocardium of hypertensive rats with abdominal aorta constriction. LVH model was established by creating abdominal aorta constriction. Four weeks later, animals were randomly divided into 4 groups with 8 animals in each. One group was used as model control, the other three groups were treated with TSN IIA (20 mg/kg), TSN IIA (10 mg/kg) and valsartan (10 mg/kg), respectively. Another 8 SD rats were subjected to sham surgery and served as blank control. After 8-week treatment, the caudal artery pressure of the animals was measured. The tissues of left ventricle were taken for the measurement of the left ventricular mass index (LVMI) and pathological sectioning and HE-staining were used for determining the myocardial fiber dimension (MFD). The mRNA expression of AT1R, protein expression of TGF-beta1 and activity of Smad-2, 4, 7 were detected by RT-PCR and Western blotting, respectively. Our results showed that (1) the blood pressure of rats treated with TSN IIA, either at high or low dose, was significantly higher than those in the control and valsartan-treated group (P<0.01, P<0.05); (2) LVMI and MFD in TSN IIA and valsartan-treated rats were higher than those in the control group (P<0.05) but significantly lower than those in the model control (P<0.01); (3) the high doses of TSN IIA and valsartan significantly down-regulated the mRNA expression of AT1R and protein expression of TGF-beta1 and Smad-3 in the hypertrophic myocardium (P<0.01), and TGF-beta1 in valsartan-treated animals was more significantly lower than that in rats treated with TSN IIA; (4) the two doses of TSN IIA and valsartan significantly up-regulated the protein expression of Smad-7 in the hypertrophic myocardium (P<0.01), and Smad-7 in the animals treated with high-dose TSN IIA was significantly higher than that in rats treated with valsartan. It is concluded that inhibition of myocardial hypertrophy induced by TSN IIA independent of blood pressure. The underlying mechanism might be the down-regulated expression of AT1R mRNA and Smad-3, increased production of Smad-7, and blocking effect of TSN IIA on TGF beta1/Smads signal pathway in local myocardium.
ABSTRACT
Background Left ventricular hypertrophy(LVH) is a cardiovascular risk factor independent of the blood pressure. JAK/STAT pathway has been confirmed to participate in cardiac hypertrophy and hyperplasia. Our previous reports have shown that sodium tanshinone ⅡA sulfonate(STS) reversed LVH,inhibited the myocardial cells Ca2+ influx,lowered left ventricular myocardial tumor necrosis factor-?(TNF-?)and the proto-oncogene c-fos,Bcl-2,and p53 protein expression. Objective To study the effect of sodium tanshinone ⅡA sulfonate(STS) on JAK/STAT pathway in left ventricular hypertrophy(LVH) induced by abdominal aorta stenosis in rats. Methods Twenty-four 9-weeks-old rats submitted to abdominal aorta constriction,were randomized to receive STS 10 mg/(kg?d)(n=8)or sterilized distilled water (1 mL/d)(n=8),or valsartan 10 mg/(kg?d) by gavage(n=8),with age and sex matched sham operated rats(n=8) as control. HE,VG and immunohistonchemical staining were used to evaluate the myocardial fiber dimension(MFD). Expressions of JAK1 and STAT3 were assessed by using Western blot. Results Compared with the control group,pressure loaded rats had higher SBP[(117.3?8.3) vs LVH: (186.5?13.5)mmHg,P
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BACKGROUND:Among the factors causing vascular endothelial cell injury,angiotensin Ⅱ(Ang Ⅱ) caused by renin-angiotensin system (RAS), especially by local RAS, plays an important patho-physiological role.OBJECTIVE: To observe the effect of tanshinone ⅡA on the vascular endothelial cells secreting nitric oxide (NO) and endothelial nitric oxide synthase (eNOS) gene expression as well as intracellular Ca2+ level induced by Ang Ⅱ, and investigate the protective effect of tanshinone ⅡA on vascular endothelial cells.DESIGN: Controlled observation experiment.SETTING: Department of Emergency, Tongji Hospital Affiliated to Tongji Medical College, Huazhong University of Science and Technology.MATERIALS: This experiment was carried out in the Experimental Center for Basic Medicine, Tongji Medical College,Huazhong University of Science and Technology from March 2006 to October 2006. Porcine aorta used in this experiment was provided by the Department of Pathophysiology of Tongji Medical College.METHODS: Nitric acid deoxidization method and reverse transcription-polymerase chain reaction (RT-PCR) were used to detect the effects of Ang Ⅱ of different concentrations (10-8 to 10-6 mol/L) on endothelial cells secreting NO and eNOS mRNA expression in cultured porcine aortic endothelial cells at different time points (1,6 and 24 hours) separately, then 50 mg/L tanshinone Ⅱ A was respectively added at different time point (0, 6 hours) when Ang Ⅱ was at 10-6 mol/L, and changes in NO production and eNOS gene expression were detected respectively at 1, 6 and 24 hours. Intracellular Ca2+ level was also detected with laser scanning confocal microscopy.MAIN OUTCOME MEASURES: ① NO content. ②eNOS mRNA expression. ③Intracellular Ca2+ level.RESULTS: ① NO production and eNOS mRNA expression were decreased with increase of Ang Ⅱ concentration and prolongation of time (P ＜ 0.01). ② NO production and eNOS mRNA expression in each tanshinone ⅡA-treated group were significantly higher than those in the Ang Ⅱ group. At 1 and 6 hours of tanshinone ⅡA treatment, production of NO and eNOS mRNA expression in the Ang Ⅱ + tanshinone ⅡA group were significantly higher than those in the Ang Ⅱ 6 hours + tanshinone ⅡA group (P ＜ 0.05); There were no significant differences in NO production and eNOS mRNA expression between two groups at 24 hours (P ＞ 0.05). ③Intracellular Ca2+ level in the Ang Ⅱ group was significantly higher than that of control group (P ＜ 0.01), and intracellular Ca2+ level in the tanshinone ⅡA + Ang Ⅱ was significantly lower than that in the Ang Ⅱ group (P ＜ 0.05).CONCLUSION: Tanshinone Ⅱ A has a protective effect on vascular endothelial cells and their functions by suppressing the inhibition of Ang Ⅱ on NO level and eNOS gene expression in cultured porcine aortic endothelial cells.
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Cardiomyocyte hypertrophy is a major cause of morbidity and mortality worldwide. The aim of this study is to determine the effects of sodium tanshinone IIA sulfonate (STS) on cardiomyocyte hypertrophy induced by angiotensin II (Ang II) in vivo and in vitro. In long-term treatment, adult Wistar rats were infused with Ang II for three weeks via osmotic mini-pumps and some of them were given intragastrically of STS. Left ventricle was isolated; the ratio of left ventricular weight to body weight and systolic blood pressure (SBP) were determined and heart morphometry was assessed after hematoxylin and eosin staining. Results indicated STS inhibited Ang II-induced increases in myocyte diameter and decreased the LVW/BW ratio independent of decreasing systolic blood pressure. In vitro, treatment of cultured cardiomyocytes with STS inhibited Ang II-induced increase in cell size, protein synthesis, ANP expression, activation of extracellular signal-regulated kinase (ERK) and ERK kinase (MEK). Then we reexamined the mechanism of STS-induced anti-hypertrophic effects. Results revealed MEK inhibitor U0126 (20 microM) markedly enhanced STS-induced depressions in [3H]leucine incorporation and ANP expression. In conclusion, MEK/ERK pathway plays a significant role in the anti-hypertrophic effects of STS.
Subject(s)
Rats , Animals , Rats, Wistar , Phenanthrenes/chemistry , Myocytes, Cardiac/drug effects , Molecular Structure , Mitogen-Activated Protein Kinase Kinases/metabolism , MAP Kinase Signaling System/drug effects , Extracellular Signal-Regulated MAP Kinases/metabolism , Enzyme Activation/drug effects , Cardiomegaly/chemically induced , Angiotensin II/antagonists & inhibitorsABSTRACT
The differences of arrhythmias among distinct left ventricular geometric patterns in the patients with essential hypertension were studied. 179 patients with essential hypertension received 24 h dynamic ECG recording, ambulatory blood pressure monitoring, echocardiography examination, etc. According to the examinations, left ventricular geometric patterns and arrhythmias were identified. The comparison of morbidity of arrhythmias between the left ventricular remodeling group and the normal geometric pattern group was performed. The multiple stepwise regression analysis was carried out to identify the independent determinants of arrhythmias. After these predictors were controlled or adjusted, the severity of arrhythmias among different left ventricular geometric patterns was compared. It was found that the morbidity of atrial arrhythmia, ventricular arrhythmia and complex ventricular arrhythmias in the left ventricular remodeling group was significantly higher than in the normal geometric pattern group respectively. There were many independent factors influencing on arrhythmias in essential hypertension. Of all these factors, some indices of left ventricular anatomic structure, grade of hypertension, left atrial inner dimension, E/A, diastolic blood pressure load value at night and day average heart rate and so on were very important. After the above-mentioned factors were adjusted, the differences of the orders of arrhythmias between partial geometric patterns were reserved, which resulted from the differences of the geometric patterns. Many factors contributed to arrhythmias of essential hypertension, such as grade of hypertension, LVMI, LA, PWT and so on. The severity of arrhythmias was different in different left ventricular geometric patterns.
ABSTRACT
The differences of arrhythmias among distinct left ventricular geometric patterns in the patients with essential hypertension were studied. 179 patients with essential hypertension received 24 h dynamic ECG recording, ambulatory blood pressure monitoring, echocardiography examination, etc. According to the examinations, left ventricular geometric patterns and arrhythmias were identified. The comparison of morbidity of arrhythmias between the left ventricular remodeling group and the normal geometric pattern group was performed. The multiple stepwise regression analysis was carried out to identify the independent determinants of arrhythmias. After these predictors were controlled or adjusted, the severity of arrhythmias among different left ventricular geometric patterns was compared. It was found that the morbidity of atrial arrhythmia, ventricular arrhythmia and complex ventricular arrhythmias in the left ventricular remodeling group was significantly higher than in the normal geometric pattern group respectively. There were many independent factors influencing on arrhythmias in essential hypertension. Of all these factors, some indices of left ventricular anatomic structure, grade of hypertension, left atrial inner dimension, E/A, diastolic blood pressure load value at night and day average heart rate and so on were very important. After the above-mentioned factors were adjusted, the differences of the orders of arrhythmias between partial geometric patterns were reserved, which resulted from the differences of the geometric patterns. Many factors contributed to arrhythmias of essential hypertension, such as grade of hypertension, LVMI, LA, PWT and so on. The severity of arrhythmias was different in different left ventricular geometric patterns.