| Ventricular remodeling is the basis for the development of heart failure. How to control, delay and reverse ventricular remodeling is critical for the treatment of heart failure. Danshensu (DSS) is a water-soluble phenolic aromatic acid, mainly derived from the roots of Danshen and Salvia. As a natural bioactive product, Danshensu is capable of oxygen free radicals elimination, peroxide degradation and antioxidation. Its antioxidant activity is stronger than Vitamin C. It is reported that Danshensu inhibits isoproterenol-induced cardiac hypertrophy through its antioxidant and cardioprotective effect, reducing the heart weight body weight ratio (HW/BW) and left ventricular weight body weight ratio (LVW/BW) significantly. Although these findings strongly suggest its cardioprotective effect, the role of Danshensu in ventricular remodeling after pressure overload has not been investigated. In this study, the model of ventricular remodeling was established by transverse aortic constriction (TAC). We aim to test the effect of Danshensu on cardiac function and ventricular remodeling after pressure overload and to explore its possible mechanism.Part I Effects of Danshensu on cardiac function and ventricular remodeling in the pressure-overload miceObjective To explore the effects of Danshensu on cardiac function and ventricular remodeling in the mice model of transverse aortic constriction.Methods C57BL/6 male mice were randomly divided into four groups:Sham-Saline, Sham-Danshensu, TAC-Saline and TAC-Danshensu. Mice ventricular remodeling model were established by transverse aortic constriction operation. The mice were fed with Danshensu or Saline for 8 weeks. Cardiac structure and function were examined by echocardiography. After echocardiographic evaluation, mice were sacrificed and the heart tissue samples were harvested. We measured heart rate (HR), body weight (BW), lung weight body weight ratio (LW/BW), heart weight body weight ratio (HW/BW) and heart weight tibia length ratio (HW/TL). RT-PCR was used to detect the expressions of atrial natriuretic peptide (ANP), B-type natriuretic peptide (BNP), a-myosin heavy chain (a-MHC) and P-myosin heavy chain (P-MHC). The heart volume and cardiomyocyte cross-sectional area were observed by HE staining.Results (1) There was no statistical significance regarding the difference in HR and BW among the four groups (p>0.05). (2) LW/BW, HW/BW and HW/TL of TAC-Saline group were higher than those of Sham-Saline group and TAC-Danshensu group (p<0.05). (3) Compared with Sham-Saline group, the cardiac function and ventricular chamber of TAC-Saline group were significantly impaired and large (p<0.05), respectively; TAC-Danshensu mice showed improved cardiac function indices compared to TAC-Saline mice as measured by echocardiography (p<0.05). (4) RT-PCR indicated that compared to Sham-Saline group, the mRNA expressions of ANP, BNP and ?-MHC was significantly increased (p<0.05), while the a-MHC mRNA level was decreased in TAC-Saline group (p<0.05); However, there was a decrease in the mRNA level of ANP, BNP and ?-MHC (p<0.05) as well as an increase in a-MHC mRNA level (p<0.05) in the TAC-Danshensu group compared with the TAC-Saline group. (5) The HE staining indicated an enlargement in heart volume and cardiomyocyte cross-sectional area after TAC, which could be ameliorated by Danshensu.Conclusions Danshensu intervention could improve cardiac function and ventricular remodeling in mice after pressure overload.Part II The effects of Danshensu on oxidative stress, myocardial apoptosis and fibrosis in ventricular remodeling after pressure overload and its mechanismObjective To explore the effects of Danshensu on oxidative stress, myocardial apoptosis and fibrosis in the mice model of transverse aortic constriction and its mechanism.Methods C57BL/6 male mice were randomly divided into four groups:Sham-Saline, Sham-Danshensu, TAC-Saline and TAC-Danshensu. Mice ventricular remodeling model were established by transverse aortic constriction operation. The mice were fed with Danshensu or Saline for 8 weeks. After echocardiographic evaluation, mice were sacrificed and the heart tissue samples were harvested. (1) Cardiomyocyte apoptosis was examined by TUNEL staining, and the intracellular ROS production was measured by DCFA-DA assay. Western blot was used to detect the expressions of apoptosis-related protein, including Caspase-3, Bax and Bcl-2. (2) The protein expressions of Nrf2, HO-1, NQO-1, y-GCS were tested by Western blot. (3) RT-PCR analysis of the mRNA content of connective tissue growth factor (CTGF), transforming growth factor-?1(TGF-?1), and type I and III collagen was performed. (4) The expression of TGF-?1/Smad signaling pathway related protein was detected by Western blot analysis. (5) Masson staining was used to determine the myocardial fibrosis.Results (1) TUNEL staining showed that the cardiomyocyte apoptosis was significantly increased in the TAC-Saline group in comparison either to the Sham-Saline group or to the TAC-Danshensu group (p<0.05); Compared to the Sham-Saline group, the ROS production was higher in the TAC-Saline group (p<0.05). However, TAC-Danshensu mice manifested a lower ROS level than TAC-Saline mice (p<0.05); The protein expressions of Bax and Caspase-3 were higher (p<0.05) in the TAC-Saline group than those in the Sham-Saline group. The TAC-Danshensu mice, however, had a lower level of Bax and Caspase-3 (p<0.05) compared with the TAC-Saline mice. There was no significant difference in terms of Bcl-2 expression across the four groups. (2) Compared to the Sham-Saline group, the Nrf2 and HO-1 protein expressions were significantly increased (p<0.05), and the NQO-1 and ?-GCS levels were dramatically decreased (p<0.05) in the TAC-Saline group. All of these proteins were higher in the TAC-Danshensu group than in the TAC-Saline group (p<0.05). (3) Compared with Sham-Saline group, the mRNA content of CTGF, TGF-?1, and type ? and ? collagen were significantly increased (p<0.05) in the TAC-Saline group. These mRNA expressions were lower in the TAC-Danshensu group than in the TAC-Saline group (p<0.05). (4) In addition to a reduction in the Smad7 protein expression, an increase in the phosphorylation of Smad2 and Smad3 and the protein level of TGF-?1 were also observed in the TAC-Saline group as compared to the Sham-Saline group (p<0.05); Compared with TAC-Saline group, the TAC-Danshensu group showed a reduced phosphorylation of Smad2 and Smad3, a decreased protein level of TGF-?1 and an increased expression of Smad7 (p<0.05). (5) Masson staining demonstrated that the myocardial fibrosis was increased after TAC (p<0.05), which could be mitigated by Danshensu intervention.Conclusions Danshensu could mitigate the oxidative stress, myocardial apoptosis and fibrosis that were induced by pressure overload. |
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