[Effects of Tanshinone II A on the myocardial apoptosis and the miR-133 levels in rats with heart failure].

OBJECTIVE: To explore the effects of Tanshinone II A (Tan II A) on the myocardial apoptosis in rats with heart failure and its mechanisms for regulating the miR- 133 levels. METHODS: The heart failure rat model was established by thoracic aorta constriction (TAC). Tan II A Injection was applied for 12 successive weeks. Meanwhile, partial heart failure rats were subcutaneously implanted with osmotic pump of antagonist to observe its inhibition on the miR-133 level. Twelve weeks later, the hemodynamic conditions, the myocardial apoptosis (using TUENL method), myocardial pro-apoptotic genes (Bax and Caspase-3), and the expressions of anti-apoptosis genes (Bcl-2) (using Western blot and RT-PCR method) were analyzed. RESULTS: Compared with the sham-operation group, TAC operation could deteriorate the heart function (except the mean arterial pressure), elevate the myocardial apoptosis level, increase the protein and mRNA levels of Bax and Caspase-3, and down-regulate the protein and mRNA levels of miR-133 and Bcl-2. TAC rats treated by Tan II A could significantly improve all indices with statistical difference except the heart rate. Subcutaneously pumping of antagonist could partially abolish the anti-apoptosis effect of Tan II A. CONCLUSION: Tan II A could decrease the myocardial apoptosis level of heart failure rats, which was possibly realized by up-regulating the miR-133 level.

Effects of tanshinone II A on the myocardial hypertrophy signal transduction system protein kinase B in rats.

OBJECTIVE: To study the effect of tanshinone II A on the cell signal transduction system protein kinase B (Akt) in rats with hypertrophy of the myocardium induced by partial constriction of the thoracic aorta. METHODS: Rat models of myocardial hypertrophy were established by the thoracic aorta partial constriction method. Forty-eight rats were randomly divided into the sham-operative group, the model group, the valsartan treatment group, and the low-, medium-, and high-dose tanshinone treatment groups. The heart mass index (HMI), left ventricular mass index (LVMI), ejection fraction (EF), left ventricular posterior wall (LVPW), and interventricular septal thickness (IVS) were detected by high-frequency ultrasonography. The myocardial fiber diameter (MFD) was detected by HE staining, and the contents of p-Akt and p-Gsk3beta in the myocardium were detected by Western blot. RESULTS: Compared with the sham-operative group, the levels of HMI, LVMI, LVPW, IVS, and MFD were increased respectively in the other groups (P<0.05); the contents of p-Akt and p-Gsk3beta were also increased in the other groups. Compared with the model group, the levels of HMI, LVMI, LVPW, IVS, and MFD were decreased respectively in all treatment groups (P<0.05); the contents of p-Akt and p-Gsk3beta were decreased in all treatment groups as well. There was no significant difference, however, among the low-, medium-, and high-dose tanshinone treatment groups and the valsartan treatment group (P>0.05). CONCLUSION: Tanshinone II A can prevent myocardial hypertrophy by its action on the protein kinase B (Akt) signaling pathway.

Sodium tanshinone IIA sulfonate attenuates angiotensin II-induced collagen type I expression in cardiac fibroblasts in vitro.

Cardiac fibrosis occurs after pathological stimuli to the cardiovascular system. One of the most important factors that contribute to cardiac fibrosis is angiotensin II (AngII). Accumulating studies have suggested that reactive oxygen species (ROS) plays an important role in cardiac fibrosis and sodium tanshinone IIA sulfonate (STS) possesses antioxidant action. We therefore examined whether STS depresses Ang II-induced collagen type I expression in cardiac fibroblasts. In this study, Ang II significantly enhanced collagen type I expression and collagen synthesis. Meanwhile, Ang II depressed matrix metalloproteinase-1 (MMP-1) expression and activity. These responses were attenuated by STS. Furthermore, STS depressed the intracellular generation of ROS, NADPH oxidase activity and subunit p47(phox) expression. In addition, N-acetylcysteine the ROS scavenger, depressed effects of Ang II in a manner similar to STS. In conclusion, the current studies demonstrate that anti-fibrotic effects of STS are mediated by interfering with the modulation of ROS.

[Effect of tashinone on nitric oxide synthase in hypertrophic cardiomyocyte of rats suffered abdominal aorta constriction].

OBJECTIVE: To explore the molecular biological mechanism for tanshinone II A reversing left ventricular hypertrophy, it would be studying the effect of tashinone on the endothelial nitric oxide synthase (eNOS) and protein kinase C (PKC) in the hypertrophic cadiocyte of rats suffered abdominal aorta constriction. METHOD: SD rats were operated with abdominal aorta constriction and 8 rats were done with sham surgery. After 4 weeks, all rats were divided into 4 groups: myocardial hypertrophy group, low dose tanshinone II A group (10 mg x kg(-1) x d(-1)), high dose tanshinone II A group (20 mg x kg(-1) x d(-1)) and valsartan group (10 mg x kg(-1) d(-1) intragastric administration). 8 weeks later, the rats were used to measure the left ventricular mass index (LVMI) with the tissue of left ventricle and myocardial fiber dimension (MFD) by pathological section and HE stain, to detect the nitric oxide content by nitrate reductase, to detect the genic expression of eNOS by RT-PCR and to detect the activity of protein kinase C (PKC) by Western blotting. RESULT: 1) The blood pressure in group myocardial hypertrophy [(186 +/- 13) mmHg] and tansginone II A [low and high dose (188 +/- 11,187 +/- 14) mmHg] was obviously higher than that in group sham surgery and valsartan group [vs (117 +/- 8, 136 +/- 15) mmHg, P < 0.01]. But there was no difference between group myocardial hypertrophy and group tanshinone II A (low and high dose). 2) The LVMI and MFD were obviously higher in group tanshinone II A low and high dose) and group valsartan than those in group sham surgery (P < 0.05), and lower than those in group myocardial hypertrophy (P < 0.01). 3) The NO level was obviously higher in group tanshinone II A (low and high dose) and group valsartan than that in group myocardial hypertrophy (12.78 +/- 1.66, 11.95 +/- 1.39, 12.26 +/- 2.08 vs 5.83 +/- 1.06) micromol x L(-1), (P < 0.01 ), and lower than that in group sham surgery (vs 19.35 +/- 1.47) micromol x L(-1), (P < 0.05). 4) The expressive level of eNOS mRNA and protein in myocardial hypertrophy group was less than that in other groups (P < 0.01). And valsartan group was less than tanshinone II A groups and sham surgery group (P < 0.05), but there were no difference among the two tanshinone II A groups and sham surgery group. 5) The level of PKC protein in group myocardial hypertrophy was obviously higher than that in all the other groups (1.291 +/- 0.117 vs 0.563 +/- 0.094, 0.605 +/- 0.051, 0.519 +/- 0.062, 0.827 +/- 0.086, P < 0.01), and the level in group valsartan was higher than that in group sham operation and group tanshinone II A (low and high dose). CONCLUSION: NO/NOS system in local myocardium has close relationship with the pathological process for myocardial hypertrophy. Tanshinone II A can produce the pharmacological action to reverse myocardial hypertrophy by inhibiting the activity of PKC and promoting the genic expression of eNOS in local myocardium and the production of endogenous NO.

Effect of sodium tanshinone II A sulfonate on phosphorylation of extracellular signal-regulated kinase 1/2 in angiotensin II-induced hypertrophy of myocardial cells.

OBJECTIVE: To observe the effects of sodium tanshinone II A sulfonate (STS) on angiotensin II (Ang II)-induced hypertrophy of myocardial cells through the expression of phosphorylated extracellular signal-regulated kinase (p-ERK1/2). METHODS: In the primary culture of neonatal rat myocardial cells, the total protein content in myocardial cells was determined by coomassie brilliant blue and the protein synthesis rate was measured by [3H]-Leucine incorporation as indexes for hypertrophy of myocardial cells. The expression of p-ERK1/2 was determined using Western blot and immunofluorescence labeling. RESULTS: (1) The total protein and protein synthesis rate increased significantly in contrast to the control group after the myocardial cells were stimulated by Ang II (1 micromol/L) for 24 h; STS markedly inhibited the increment of the total protein level induced by Ang II and the syntheses of protein. (2) After pretreatment of myocardial cells with Ang II (1 micromol/L) for 5 min, the p-ERK1/2 protein expression was increased, with the most obvious effect shown at about 10 min; pretreatment of myocardial cells with STS at different doses (2, 10, 50 micromol/L) for 30 min resulted in obvious inhibition of the expression of p-ERK1/2 stimulated by Ang II in a dose-dependent manner. (3) After the myocardial cells were stimulated by Ang II (1 micromol/L), the immunofluorescence of ERK1/2 rapidly appeared in the nucleus. The activation and translocation process of ERK1/2 induced by Ang II was blocked distinctly by STS. CONCLUSION: STS inhibited the myocardial cell hypertrophy induced by Ang II, and the mechanism may be associated with the inhibition of p-ERK1/2 expression.

[Changes of c-fos, c-jun mRNA expressions in cardiomyocyte hypertrophy induced by angiotensin II and effects of tanshinone II A].

OBJECTIVE: To investigate the changes of proto-oncogene c-fos, c-jun mRNA expression in angiotensin II (Ang II)-induced hypertrophy and effects of tanshinone II A (Tan) in the primary culture of neonatal rat cardiomyocytes. METHOD: Twelve neonatal Wistar rats aged one day old of clean grade and both sexes were selected to isolate and culture cardiomyocytes. The cardiomyocytes were divided into: normal control group, Ang II (10(-6) mol x L(-1)) group, Ang II (10(-6) mol x L(-1)) +Tan (10(-8) g x L(-1)) group, Ang II (10(-6) mol x L(-1)) + valsartan (10(-6) mol x L(-1)) group, Tan (10(-8) g x L(-1)) group, valsartan (10(-6) mol x L(-1)) group. The cardiomyocyte size was determined by phase contrast microscope, the rate of protein synthesis in cardiomyocytes was measured by 3H-leucine incorporation. The c-fos, c-jun mRNA expression of cardiomyocytes were assessed using reverse transcription polymerase chain reaction (RT-PCR). RESULT: Ang II was added to the culture medium and 30 min later, the c-fos, c-jun mRNA expression of cardiomyocytes increased significantly (P < 0. 01). After Ang II took effect for 24 h, the rate of protein synthesis in Ang II group increased more prominently than that in normal control group (P < 0.01). After Ang II took effect for 7 days, the size of cardiomyocyte in Ang II group increased obviously (P < 0. 05). If tanshinone II or valsartan was added to the culture medium before Ang II, both of them could inhibit the increase of c-fos, c-jun mRNA expression (P < 0.01), cardiomyocyte protein synthesis rate (P < 0.01), and cardiomyocyte size (P < 0.05) induced by Ang II. CONCLUSION: Tanshinone II could ameliorate Ang II-induced cardiomyocytes hypertrophy by inhabiting c-fos, c-jun mRNA expression.

[Effect of tanshinone II A on angiotensin II induced nitric oxide production and endothelial nitric oxide synthase gene expression in cultured porcine aortic endothelial cells].

OBJECTIVE: To investigate the protective effect of tanshinone II A on porcine aortic endothelial cells (PAEC). METHODS: PAEC were stimulated with angiotensin II (Ang- II) for different acting time (1 h, 6 h and 24 h) and Tanshinone II A was added along with Ang- II stimulation (Group A) or 6 h after it (Group B). The nitric oxide (NO) level, the protein and mRNA expression of nitric oxide synthase (cNOS) in PAEC were measured by nitric acid deoxidizing assay, RT-PCR and immunohistochemical assay, respectively. RESULTS: With the prolongation of acting time of Ang- II, the level of NO and eNOS expression in PAEC sequentially decreased in a negative acting time dependent manner (P < 0.01), which could be inhibited by tanshinone II A treatment independent to the dosage used (P< 0.01). The inhibitory effect of tanshinone II A was better in Group A than that in Group B either at 1 h or at 6 h after treatment (P<0.05). However, 24 h later, no significant difference was found between the effect in the two groups (P >0.05). CONCLUSION: Tanshinone II A could inhibit the negative effect of Ang- II on NO production and eNOS expression in PAEC.