Tongxinluo protects against pressure overload-induced heart failure in mice involving VEGF/Akt/eNOS pathway activation.

BACKGROUND: It has been demonstrated that Tongxinluo (TXL), a traditional Chinese medicine compound, improves ischemic heart disease in animal models via vascular endothelial growth factor (VEGF) and endothelial nitric oxide synthase (eNOS). The present study aimed to investigate whether TXL protects against pressure overload-induced heart failure in mice and explore the possible mechanism of action. METHODS AND RESULTS: Transverse aortic constriction (TAC) surgery was performed in mice to induce heart failure. Cardiac function was evaluated by echocardiography. Myocardial pathology was detected using hematoxylin and eosin or Masson trichrome staining. We investigated cardiomyocyte ultrastructure using transmission electron microscopy. Angiogenesis and oxidative stress levels were determined using CD31 and 8-hydroxydeoxyguanosine immunostaining and malondialdehyde assay, respectively. Fetal gene expression was measured using real-time PCR. Protein expression of VEGF, phosphorylated (p)-VEGF receptor 2 (VEGFR2), p-phosphatidylinositol 3-kinase (PI3K), p-Akt, p-eNOS, heme oxygenase-1 (HO-1), and NADPH oxidase 4 (Nox4) were measured with western blotting. Twelve-week low- and high-dose TXL treatment following TAC improved cardiac systolic and diastolic function and ameliorated left ventricular hypertrophy, fibrosis, and myocardial ultrastructure derangement. Importantly, TXL increased myocardial capillary density significantly and attenuated oxidative stress injury in failing hearts. Moreover, TXL upregulated cardiac nitrite content and the protein expression of VEGF, p-VEGFR2, p-PI3K, p-Akt, p-eNOS, and HO-1, but decreased Nox4 expression in mouse heart following TAC. CONCLUSION: Our findings indicate that TXL protects against pressure overload-induced heart failure in mice. Activation of the VEGF/Akt/eNOS signaling pathway might be involved in TXL improvement of the failing heart.

Tongxinluo Improves Cardiac Function and Ameliorates Ventricular Remodeling in Mice Model of Myocardial Infarction through Enhancing Angiogenesis.

Background. Myocardial infarction (MI) is a major cause of morbidity and mortality in the world. Tongxinluo (TXL) is a traditional Chinese compound prescription which has cardioprotective functions. The present study was aimed to determine the effect of TXL on postischemic cardiac dysfunction and cardiac remodeling and to elucidate the underlying mechanisms. Methods and Results. MI was performed by ligation of left anterior descending coronary artery (LAD) in male adult mice. Mice were randomly divided into four groups: (1) sham group (Sham); (2) MI-control group (Control); (3) MI-low dose TXL group (TXL-L); and (4) MI-high dose TXL (TXL-H) group. Compared with the control group, TXL treatment restored cardiac function, increased revascularization, attenuated cardiomyocyte apoptosis, and reduced interstitial fibrosis. TXL treatment increased the phosphorylation of Akt, extracellular signal regulated kinase (ERK), and endothelial nitric oxide synthase (eNOS); the expression of phosphatidylinositol3-kinase (PI3K), hypoxia-inducible factors 1 α (HIF-1 α ), and vascular endothelial growth factor (VEGF); and the DNA binding activity of HIF-1 α after MI. Conclusion. TXL may improve cardiac function and ameliorate cardiac remodeling by increasing neovascularization through enhancing the phosphorylation of Akt and ERK, the expression and activity of HIF-1 α , and the protein level of VEGF and p-eNOS.

Rehmannia glutinosa extract activates endothelial progenitor cells in a rat model of myocardial infarction through a SDF-1 α/CXCR4 cascade.

OBJECTIVES: Endothelial progenitor cells (EPCs) can be used to repair tissues after myocardial infarction (MI) but EPC activators have adverse reactions. Rehmannia glutinosa is a herb used in traditional Chinese medicine, which can promote bone-marrow proliferation and protect the ischemic myocardium. We investigated the effects of Rehmannia glutinosa extract (RGE) on EPCs in a rat model of MI. METHODS: A total of 120 male Wistar rats were randomized to 2 groups (n=60 each) for treatment: high-dose RGE (1.5 g·kg(-1)·day(-1) orally) for 8 weeks, then left anterior descending coronary artery ligation, mock surgery or no treatment, then RGE orally for 4 weeks; or normal saline (NS) as the above protocol. The infarct region of the left ventricle was assessed by serial sectioning and morphology. EPCs were evaluated by number and function. Protein and mRNA levels of CD133, vascular endothelial growth factor receptor 2 (VEGFR2), chemokine C-X-C motif receptor 4 (CXCR4), stromal cell-derived factor-1α (SDF-1α) were measured by immunohistochemistry, Western blot and quantitative PCR analysis. RESULTS: RGE significantly improved left ventricular function, decreased the ischemic area and the apoptotic index in the infarct myocardium, also decreased the concentration of serum cardiac troponin T and brain natriuretic peptide at the chronic stage after MI (from week 2 to week 4). RGE increased EPC number, proliferation, migration and tube-formation capacity. It was able to up-regulate the expression of angiogenesis-associated ligand/receptor, including CD133, VEGFR2 and SDF-1α/CXCR4. In vitro, the effect of RGE on SDF-1α/CXCR4 cascade was reversed by the CXCR4 specific antagonist AMD3100. CONCLUSION: RGE may enhance the mobilization, migration and therapeutic angiogenesis of EPCs after MI by activating the SDF-1α/CXCR4 cascade.