To investigate the molecular mechanism by which Tanshinone Ⅱ A （TSN Ⅱ A） prevents left ventricular hypertrophy （LVH）, we examined the expression of AT1R, TGF-β1 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-betal 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 Ⅱ A, 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 Ⅱ A 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 Ⅱ A and valsartan significantly down-regulated the mRNA expression of AT 1R and protein expression of TGF-beta l and Smad-3 in the hypertrophic myocardium （P〈0.01）, and TGF-betal in valsartan-treated animals was more significantly lower than that in rats treated with TSN Ⅱ A; （4） the two doses of TSN Ⅱ A 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
Objective： To study the effect of tanshinone ⅡA 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-Gsk3β 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-Gsk3β 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-Gsk3β 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 HE A can prevent myocardial hypertrophy by its action on the protein kinase B （Akt） signaling pathway.
Objective： To investigate the effects of sodium tanshinone Ⅱ A sulfonate （STS） on the hypertrophy induced by angiotensin Ⅱ（Ang Ⅱ） in primary cultured neonatal rat cardiac myocytes. Methods： The effect of STS on cytotoxicity was evaluated using the 3-（4,5-dimethylthiazol-2-yl）-3,5- phenytetrazoliumromide （MTT） assay. As indexes for cardiocyte hypertrophy, cell size was determined by phase contrast microscopy and protein synthesis rate was measured by 3H-leucine incorporation. The proto-oncogene c-fos mRNA expression of cardiocytes was assessed using reverse transcription polymerase chain reaction （RT-PCR）. Results： STS could inhibit cardiocyte hypertrophy, increase the protein synthesis rate and enhance proto-oncogene c-fos mRNA expression in cardiocytes induced by Ang Ⅱ（P〈0.01）, with an effect similar to that of Valsartan, the Ang Ⅱ receptor antagonist. Conclusion： STS can prevent the hypertrophy of cardiac myocytes induced by Ang Ⅱ, which may be related to its inhibition of the expression of proto-oncogene c-fos mRNA.
