| BackgroundAs estimated by World Health Organization (WHO), cardiovascular disease will be the leading cause of death by the year2020. Heart failure (HF) is the end-stage of many cardiovascular diseases, and ventricular remodeling is thought to be the internal reason for the occurrence and development of HF. In the situation that the stimulus are present, persistent of cardiac hypertrophy will be decompensated. This is associated with a significant increase in the risk for arrhythmia, sudden death or progression to heart failure. The pathological changes of ventricular remodeling are characterized by the expansion of the ventricular chamber, an increase in heart weight, enhanced cardiomyocyte hypertrophy and apoptosis, and a higher organization of the sarcomere. These changes in cellular phenotype are preceded and accompanied by the re-induction of the so-called fetal gene program. Although great progress has been made in drugs, the mortality of heart failure is still high, therefore, it is necessary to find new therapeutic targets aimed at improving ventricular remodeling.In1956, Dr. Denham Harman put forward the free radical theory for the first time, which states that the excess endogenous free radicals can cause accumulated damages to cellular DNA, proteins, lipids and cell components. However, a growing number of studies demonstrated the favorable biological effects of free radicals, such as regulation of vascular tone, sensing of oxygen tension and enhancement of membrane receptor signal transduction. Therefore, free radicals could be a double-edged sword, the balance of its generation and clearance maintains the stability of the environment. Oxidative stress usually occurs when there are more free radicals than antioxidants in the cell, which may lead to oxidative damage and a number of diseases. Oxidative stress plays a causative role in the pathogenesis of cardiovascular disease including atherosclerosis, cardiac hypertrophy and heart failure. Although, oxidative stress appears to be an important part of many human diseases, it has even been suggested that moderate levels of oxidative stress may activate endogenous protective system. Therefore, a novel strategy for the treatment of cardiovascular disease may be achievable by more specific targeting the endogenous antioxidant defense system. However, specific targets and approaches for the development of antioxidant therapeutic strategies remain to be established.NF-E2-related factors (Nrfs) is a member of the Cap 'n' Collar (CNC) family of basic leucine zipper (bZip) transcription factors that includes NF-E2, Nrf1-3, and Bach1-2. Nrfs include Nrfl, Nrf2and Nrf3, among which Nrf2retains the strongest transactivation activity. As so far, the mechanism of Nrf2activation has not yet been fully elucidated, which is mainly related to the dissociation of the Keapl-Nrf2complex. In addition, other mechanisms regulating Nrf2activity, such as phosphorylation, competitive inhibition and post-transcriptional modification are still being studied. Nrf2is ubiquitously expressed in the cardiovascular system. Nrf2regulates the intracellular redox balance by regulating the expression of antioxidant genes, and is an important regulatory factor for various cardiovascular diseases.According to Traditional Chinese Medicine (TCM) theory, the physiological and pathological changes of body are caused by the yin and yang change. When the balance is broken, disease occurs. Although there is no exact concept of "oxidative stress" in TCM theory, the foundation and core of TCM theory-Yin and Yang theory, has much in common with the theory of oxidative stress. For example, the balance is not static but a dynamic equilibrium; it will lead to aging or disease, if the dynamic equilibrium is broken; yin and yang, oxidation and reduction, both are in conflict but at the same time mutually dependent; both of them reflect the importance to maintain the stable environment of body from different angles. Nevertheless, the yin and yang is a summary for the opposite attributes in all objects and phenomena, which can not be equivalent to the oxidative stress theory, the connection between the two theories still need to be further explored.For studying the effects of antioxidant stress factor Nrf2on ventricular remodeling, we established transverse aortic constriction (TAC) model in Nrf2knockout mice and Nrf2transgenic mice respectively, observed the effects of Nrf2on ventricular remodeling, and further explored the possible mechanisms.Objectives(1) To observe ventricular remodeling in Nrf2knockout mice and Nrf2transgenic mice respectively after TAC;(2) To explore the possible protective mechanisms of Nrf2in ventricular remodeling.Materials and methods1. Animals and GroupsThe background of Nrf2knockout mice is ICR/SV129. Nrf2+/+and Nrf2-/-mice were generated according to the breeding procedures previously.52male Nrf2+/+and Nrf2-/-mice at8or9weeks of age were used in the present study. They were randomly divided into4groups:Nrf2+/+sham group(n=13), Nrf2+/+TAC group (n=13), Nrf2-/-sham group (n=13) and Nrf2-/-TAC group (n=13).The background of Nrf2transgenic mice is FVB/NJ,44male Nrf2wt and Nrf2tg mice at8to10weeks of age were used in the present study. They were randomly divided into4groups:Nrf2wt sham group (n=11), Nrf2wt TAC group (n=11), Nrf2tg sham group (n=11) and Nrf2tg TAC group (n=11).2. Genotyping for MiceAfter anesthetized by isoflurane, the mice were punched in ears and cut tails. DNA was extracted from tails using DNA extraction kit. Following amplification, the PCR products were identified by running gel electrophoresis.3. Echocardiographic AnalysisNrf2knockout mice:Echocardiography was performed on d0, d14, d21and d28 after TAC surgery.Nrf2transgenic mice:Echocardiography was performed on d0, d14and d28after TAC surgery.Echocardiography was performed on anesthetized mice, using the Vevo770High-Resolution Imaging System with a37.5-MHz high-frequency linear transducer. Two-dimensionally (2D) short-axis images of left ventricle were obtained. A2D guided M-mode echo cardiogram was recorded at level of the papillary muscles. Measurements were then performed to obtain the heart rate (HR), LV internal dimension (LVID) and LV posterior wall thickness (LVPW). LV percent fractional shortening FS (%) was calculated according to the following formula:LVFS=[(LVIDd-LVIDs)/LVIDd]×100%4. Establish TAC ModelAfter anesthetized by isoflurane, the mice of TAC groups were subjected to transverse aortic arch constriction (TAC). The use of a horizontal incision at the level of the suprasternal notch allows direct visualization of the transverse aorta without entering the pleural space and thus obviates the need for mechanical ventilation. The transverse aorta was banded between the right innominate and left carotid arteries to the diameter of a27-gauge needle using a7-0silk suture. Sham operations were only omitted the actual aortic banding and served as a control for all experimental groups.5. Preparation of SpecimensThe mice were executed4weeks after TAC. After infusion, the heart and lung were rapidly removed and weighed. The left tibia was separated and measured the length.6. Tissue StainingThe hearts were harvested for Masson staining, WGA staining.7. Immunohistochemical StainingThe hearts were harvested for TUNEL staining,4-HNE and8-OHdG immunofluorescent staining.8. Real-time RT-PCRThe mRNA expression of ANF, BNP, α-MHC, β-MHC, SERCA2a, NQO-1, HO-1, Txn-1and Txnrd-1in left ventricular was measured, and the housekeeper gene GAPDH was used as a reference.9. Statistical AnalysisAll data are expressed as x±SD, the differences between groups were compared using ANOVA analysis. SPSS statistical software was used for statistical analysis, and P<0.05was considered statistically significant.Results1. Genotyping for miceIn electrophoresis result of Nrf2knockout mice, the band for Nrf2+/+was about700bp, the band for Nrf2-/-mice was about400bp, and two bands for Nrf2+/-mice include700bp and400bp.In electrophoresis result of Nrf2transgenic mice, the band for Nrf2tg mice was about1058bp, and Nrf2wt mice have no bands.2. General state of the experimental animalsIn Nrf2knockout mice, no mice died after sham operation. After TAC, the survival rate of Nrf2+/+mice was84.62%(11/13), while the survival rate of Nrf2-/-mice was76.92%(10/13). There were47mice completing the experiment:13mice in Nrf2+/+sham group,11mice in Nrf2+/+TAC group,13mice in Nrf2-/-sham group and10mice in Nrf2-/-TAC group. There was no significant difference on body weight between groups.In Nrf2transgenic mice, no mice died after sham operation. After TAC, the survival rate of Nrf2wt mice was72.73%(8/11), while the survival rate of Nrf2tg mice was81.82%(9/11). There were39mice completing the experiment:11mice in Nrf2wt sham group,8mice in Nrf2wt TAC group,11mice in Nrf2tg sham group and9mice in Nrf2tg TAC group. There was no significant difference on body weight between groups.3. Cardiac function changes in miceIn Nrf2knockout mice, compared to sham group,14days after TAC, the Nrf2-/-and Nrf2+/+mice exhibited enhanced cardiac hypertrophy, including increases in LVPWd and LVIDs, FS was significantly decreased, demonstrating a worse pathological ventricular remodeling in TAC group mice. On the28th day, the cardiac dysfunction of Nrf2-/-TAC mice was worse than that of Nrf2+/+TAC mice. There was no significant difference between mice of sham groups.In Nrf2transgenic mice,14days after TAC, compared to sham groups, the Nrf2wt and Nrf2tg mice exhibited enhanced cardiac hypertrophy, including increases in LVPWd, LVIDd and LVIDs, FS was significantly decreased. On the28th day, the cardiac dysfunction of Nrf2tg TAC mice was better than that of Nrf2wt TAC mice. There was no significant difference between mice of sham groups.4. Heart weight, lung weight and myocyte size in miceIn Nrf2knockout mice, there was no significant difference on heart weight, lung weight and myocyte size between Nrf2+/+sham group and Nrf2-/-sham group.4weeks after TAC, adaptive hypertrophy was caused by progressive overload. The heart weight, lung weight and myocyte size of Nrf2-/-TAC group were all greater than that of Nrf2+/+TAC group, which suggested that the cardic function of Nrf2-/-TAC mice was worse than that of Nrf2+/+TAC mice.In Nrf2transgenic mice,4weeks after TAC, the heart weight, lung weight and myocyte size of Nrf2wt TAC group were all greater than that of Nrf2tg TAC group, and there was no significant difference between Nrf2wt sham group and Nrf2tg sham group. The result demonstrated that Nrf2over expression could inhibit hypertrophy caused by heart overload.5. Heart fibrosis in miceIn Nrf2knockout mice, the Masson staining in LV of sham groups was negative.4weeks after TAC, the fibrosis area of Nrf2+/+mice was13.05%, while the fibrosis area of Nrf2-/-mice was22.34%, which was similar to the fibrosis in IVS. The result suggested that Nrf2knockout induced LV fibrosis caused by pressure overload.In Nrf2transgenic mice,4weeks after TAC, the hearts were harvested and stained. The LV fibrosis area of Nrf2wt TAC mice was11.89%, while the LV fibrosis area of Nrf2tg TAC mice was8.96%. However, there was no significant difference on IVS fibrosis area between the two groups. The result suggested that Nrf2over expression could inhibit LV fibrosis caused by pressure overload. 5. Cardiomyocyte apoptosis in miceIn Nrf2knockout mice,4weeks after TAC, TUNEL-positive cells were increased compared with the sham-operated mice. In Nrf2++TAC group, TUNEL-positive cells were increased10-fold compared with the Nrf2+/+sham group. In Nrf2-/-hearts after TAC, the apoptotic cells were further increased by about14-fold compared with the sham-operation. These results indicated that Nrf2deficiency increased overall myocardial apoptosis after pressure overload.In Nrf2transgenic mice,4weeks after TAC, TUNEL-positive cells were increased compared with the sham-operated mice. However, there was no significant difference between Nrf2wt TAC mice and Nrf2tg TAC mice. The results indicated that Nrf2over expression could not inhibit overall myocardial apoptosis after pressure overload.6. Fetal gene induction in micePressure overload resulted in the activation of the fetal hypertrophic gene program including an upregulation of ANF, BNP, and β-MHC, as well as a downregulation of α-MHC and SERCA2a, in Nrf2tg TAC mice. TAC resulted in a further increase in the mRNAs of ANF, BNP, and β-MHC as well as a further decrease in the mRNAs of α-MHC and SERCA2a in Nrf2wt TAC mice. Therefore, Nrf2overexpression further decreased the ratio of α-MHC/(3-MHC in the heart, inhibited fetal gene expression and protected heart from ventricular remodeling.7. Cardiac oxidative stress in miceIn Nrf2knockout mice, myocardial levels of4-HNE and8-OHdG were significantly increased in mice4weeks after TAC. The TAC-induced oxidative stress was further exaggerated in the hearts of Nrf2-/-mice. These results demonstrate that Nrf2deficiency leads to increased oxidative stress in the heart secondary to pathological pressure overload.In Nrf2transgenic mice, there were no apparent differences of4-HNE and8-OHdG levels in the hearts of sham operated mice.4-HNE and8-OHdG were significantly increased in mice4weeks after TAC. The TAC-induced oxidative stress was alleviated in the hearts of Nrf2tg mice. These results demonstrate that Nrf2over expression leads to decreased oxidative stress in the heart secondary to pathological pressure overload.8. The expression of Nrf2downstream genes in miceIn Nrf2knockout mice, there were no apparent differences of Nrf2downstream genes mRNA expression in the hearts of sham operated mice.4weeks after TAC, the mRNA expression of Nrf2downstream genes including HO-1, NQO-1, Txn-1and Txnrd-1, were further increased in Nrf2tg TAC mice compared with those in Nrf2wt TAC mice. These results indicate that endogenous Nrf2coordinates a group of its downstream antioxidant genes to suppress cardiac oxidative stress in the heart in response to pathological pressure overload.ConclusionsTranscription factor Nrf2could inhibit overload-induced cardiac myocyte hypertrophy, apoptosis and fibrosis; induce the mRNA expression of its downstream antioxidant factors (HO-1, NQO-1, Txn-1and Txnrd-1); regulate the normal expression of fetal genes (a-MHC, P-MHC, ANF and BNP); maintain redox equilibrium. Nrf2is a critical regulator in regulation of cardiac contraction and relaxation, inhibition of ventricular remodeling and cardiac function improvement. BackgroudIn recent years, the morbidity and mortality of cardiovascular diseases are increasing, which diminish quality of human life and health. Ventricular remodeling, involved in many cardiovascular disease development, is an important risk factor for myocardial ischemia, arrhythmia and sudden cardiac death. Therefore, it is important to increase myocardial cell activity and inhibit myocardial cell hypertrophy, which will provide new perspectives for the prevention and treatment of various cardiovascular diseases.Underlying pathologic stimulus, such as ischemia, myocardial infarction and increased pressure overload, the heart will occur compensatory response characterized by ventricular remodeling, including cardiomyocyte hypertrophy, increased protein synthesis, the formation of new sarcomeres, increased ventricular wall thickness and myocardial contractility, eventually leading to cardiac dysfunction. Therefore, abnormal myocardial cells is an important part of the development and progression of ventricular remodeling.Recent studies show that oxidative stress is an important factor leading to abnormalities of the cardiovascular system, which is related to hypertension, atherosclerosis, myocardial infarction, cardiomyopathy and many other cardiovascular diseases. Oxidative stress occurs when the rate of ROS production outstrips the capacity of antioxidant systems to detoxify them. Excess ROS will attack cell and further cause cell dysfunction, such as lipid oxidation and DNA mutations, leading to irreversible cell damage or death. One of the most important cellular defense mechanisms against oxidative stress is mediated by the transcription factor Nuclear factor E2-related factor2(Nrf2). It is improtant for cell to protect ingagainst the adverse effects of exogenous injury factors and to maintain celluar steady-state redox.Nrf2is ubiquitously expressed in the cardiovascular system. Increasing studies show that Nrf2is closely related to the activity of myocardial cells. In our previous experiment, after transverse aortic constriction, Nrf2knockout mice shew reduced cardiomyocyte hypertrophy and apoptosis, and severe fibrosis cardiac function, which were improved in Nrf2transgenic mice. Therefore, Nrf2can protect the normal biological functions of myocardial cells by regulating the intracellular redox balance and maintaining homeostasis.Angiotensin-converting enzyme inhibitors (ACEI) and beta blockers, relieving heart failure by inhibiting oxidative stress, are the clinical basic drugs for the treatment of heart failure and other cardiovascular diseases. Pharmacological studies find that American ginseng has a wide regulation on nervous system, endocrine system and cardiovascular system, among them, the relationship between American ginseng and oxidative stress injury is a field worthy of study.The long-term use of American ginseng can increase the antioxidant capacity of the myocardium, however, the cellular mechanism of multidirectional protective effects on cardiovascular mediated by American ginseng is still unclear. Nrf2is an important regulator of cellular oxidative stress. It needs further study whether myocardial protective effects of American ginseng are related to its regulation of Nrf2. In the present study, using H9C2cell, we induced hypertrophy by phenylephrine (PE) and oxidative damage by hydrogen peroxide (H2O2) in vitro, respectively, and observed the effects of American ginseng extract on cell activity, hypertrophy and oxidative stress, and further explored if the possible protective mechanism was related to Nrf2. Objectives(1) To establish hypertrophy and oxidative damage model invitro;(2) To observe the effects of American ginseng extract on cell activity, hypertrophy and oxidative stress, and further explore the possible protective mechanisms.Materials and methods1. Culture H9C2cell and do the following experiments.2. Cell viability measured by MTS.3. Cell hypertrophy measured by [3H]-Leucine incorporation.4. Intracellular ROS detected by dihydroethidium.5. Preparation of DH5a competent cell.6. Cell transformation.7. Plasmid amplification and extraction.8. Transcriptional activity of Nrf2detected by Dual-Luciferase(?) Reporter Assay System.9. Nrf2protein expression detected by western blot.10. Statistical Analysis.All data are expressed as x±SD, the differences between groups were compared using ANOVA analysis. SPSS statistical software was used for statistical analysis, and P<0.05was considered statistically significant.Results1. The effects of American ginseng extract on cell viability50μg/ml,100μg/ml and500μg/ml of American ginseng extract could promote the proliferation and viability of H9C2cell, however, cell viability was decreased in the concentration of1000μg/ml and2000μg/ml. Therefore,50μg/ml,100μg/ml and500μg/ml of American ginseng extract were used in subsequent trials for further study.2. The effects of American ginseng extract on cell hypertrophy induced by PEUsing [3H]-Leucine incorporation to measure bacterial protein synthesis rates, cardiomyocyte hypertrophy was induced PE, which was inhibited after the addition of American ginseng extract (500μg/ml). There was no significant difference between the control group and American ginseng extract treatment group. The results suggested that American ginseng extract inhibited PE-induced myocardialcell hypertrophy.3. The effects of American ginseng extract on cellular oxidative stress induced by H2O2Compared with H2O2(100μM) treatment group, the intracellular ROS generation was significantly decreased by American ginseng extract (500μg/m)+H2O2treatment, indicating that American ginseng extract inhibited the H2O2-induced oxidative damage in H9C2cell.4. The effects of American ginseng extract on transcriptional activity of Nrf2The value of fluorescence was increasing with the increasing concentration of American ginseng extract, and reached the maximum at500μg/ml, which demonstrated that American ginseng extract could promote the transcriptional activity of Nrf2in H9C2cells.5. The effects of American ginseng extract on Nrf2protein expressionAfter the cells were incubated with American ginseng extract of different concentrations (50μg/ml,100μg/ml and500μg/ml) for12h, Nrf2protein expression was increased in a concentration dependent manner. This suggests that American ginseng extract could promote the protein expression of Nrf2in H9C2cells.Conclusions(1) American ginseng extract inhibits cell hypertrophy induced by PE;(2) American ginseng extract inhibits cell oxidative damage induced by H2O2;(3) The protective effects of American ginseng extract is related to promote the transcriptional activity and protein expression of Nrf2. BackgroudCardiovascular disease continues to be the leading cause of morbidity and mortality in the world, and heart failure is a final stage of many cardiovascular diseases. The progression to terminal decompensated heart failure (HF) is characterized by pathological remodeling of the left ventricle (LV), therefore, prevention of ventricular remodeling is an important for the treatment of cardiac failure.With the stimulation of the neurohormonal factors, hypertension, myocardial injury or pressure overload, the cardiac compensatory response will occur to pump enough blood to meet the body's demands. However, persistent stress will result in ventricular remodeling, which is characterized by changes in heart size, shape, myocardial cell number, fibrosis and myocardial structure, and ultimately stroke, cardiac failure and sudden death caused by the deterioration of heart function. Some studies found that oxidative stress played an important role in the development of cardiac hypertrophy and heart failure. However, the large-scale clinical study found that it was ineffective or even harmful to remove the reactive oxygen species by long-term use of vitamin in the treatment of cardiovascular disease. Because moderate levels of oxidative stress may activate endogenous protective system, excessive free radical scavenging not only inhibits the beneficial biological effects of free radicals, but also disrupts the redox system balance. Therefore, a novel strategy for the treatment of cardiovascular disease may be achievable by more specific targeting the endogenous antioxidant defense system. NF-E2-related factor2(Nrf2) is a transcription factor initiating endogenous antioxidant response, which is widely expressed in the cardiovascular system. In our previous experiments in vivo, using Nrf2knockout mice and Nrf2transgenic mice, we confirmed that Nrf2could inhibit cardiac myocyte hypertrophy, apoptosis, fibrosis and fetal gene expression by regulating the oxidative stress response in transverse aortic constriction (TAC)-induced ventricular remodeling, improve cardiac function, and inhibit the further development of ventricular remodeling.Currently, the effects of drugs for left ventricular remodeling including angiotensin-converting enzyme inhibitors (ACEI), beta-blockers and statins have been demonstrated in the occurrence and development of heart failure. However, some disadvantages, such as side effects, high price and short-term use, limit the use for some patients. There is a wealth of herbal medicine resources in China. American ginseng, which is widely used for the treatment of cardiovascular disease in clinic, has good effect on nourishing the heart. In our previous experiments in vitro, we found that American ginseng could inhibit phenylephrine-induced hypertrophy and H2O2-induced oxidative damage in H9C2cells. It's mechanism was related to the increase of Nrf2transcriptional activity and protein expression. Consideration of results of in vivo experement that Nrf2inhibited ventricular remodeling induced by pressure overload, we hypothesized that American ginseng could inhibit the ventricular remodeling induced by TAC model in mice.Therefore, with echocardiography, immunohistochemistry and molecular biology technology, we established TAC model in mice and observed the effects of American ginseng on ventricular remodeling and myocardial oxidative stress. The study can help development of new drugs for ventricular remodeling by regulating the redox balance and provide new evidence for the clinical application of American ginseng. Objectives(1) To observe the effects of American ginseng on ventricular remodeling induced by TAC in mice;(2) To observe the effects of American ginseng on myocardial oxidative stress in TAC model.Materials and methods1. Animals and Groups48ICR mice at8weeks of age were randomly divided into4groups:control sham goup (n=12), control TAC group (n=12), American ginseng sham group (n=12) and American ginseng TAC (n=12). The control group received gavage feed with0.5ml/d0.9%NaCl, and American ginseng group received50mg/kg/d American ginseng diluted by0.9%NaCl. All mice were sacrificed after4weeks.2. Echocardiographic AnalysisEchocardiography was performed on d0, d14and d28after TAC surgery using the Vevo770High-Resolution Imaging System with a37.5-MHz high-frequency linear transducer. Two-dimensionally (2D) short-axis images of left ventricle were obtained. A2D guided M-mode echocardiogram was recorded at level of the papillary muscles. Measurements were then performed to obtain the heart rate (HR), LV internal dimension (LVID) and LV posterior wall thickness (LVPW). LV percent fractional shortening FS (%) was calculated according to the following formula:LVFS=[(LVIDd-LVIDs)/LVIDd]×100%3. Establish TAC ModelAfter anesthetized by isoflurane, the mice of TAC groups were subjected to transverse aortic arch constriction (TAC). The use of a horizontal incision at the level of the suprasternal notch allows direct visualization of the transverse aorta without entering the pleural space and thus obviates the need for mechanical ventilation. The transverse aorta was banded between the right innominate and left carotid arteries to the diameter of a27-gauge needle using a7-0silk suture. Sham operations were only omitted the actual aortic banding and served as a control for all experimental groups. 4. Preparation of SpecimensThe mice were executed4weeks after TAC. After infusion, the heart and lung were rapidly removed and weighed. The left tibia was separated and measured the length.5. Tissue StainingThe hearts were harvested for Masson staining, WGA staining.6. Immunohistochemical StainingThe hearts were harvested for TUNEL staining,4-HNE and8-OHdG immunofluorescent staining.7. Real-time RT-PCRThe mRNA expression of ANF, BNP, α-MHC, β-MHC, Nrf2, HO-1, Txnrd-1and NQO-1in left ventricular was measured, and the housekeeper gene GAPDH was used as a reference.8. Western BlotThe protein expression of Nrf2in left ventricular was detected by western blot.9. Statistical AnalysisAll data are expressed as x±SD, the differences between groups were compared using ANOVA analysis. SPSS statistical software was used for statistical analysis, and P<0.05was considered statistically significant.Results1. General state of the experimental animalsDuring the experiment, no mice died in control sham group, and one mice died in gavage feedings in control American ginseng group. After TAC, the survival rate of control TAC group was75%(9/12), while the survival rate of American ginseng TAC group was83.3%(10/12). There were42mice completing the experiment:12mice in control sham goup,9mice in control TAC group,11mice in American ginseng sham group and10mice in American ginseng TAC group.2. The effects of American ginseng on cardiac function changes in miceAfter TAC operation, compared to the sham groups, the value of LVIDd, LVIDs and LVPWd were increased in both control TAC and American ginseng TAC group, while the LVFS was decreased. The value of LVIDs and LVPWd was lower in American ginseng TAC group than that in control TAC group, and LVFS was higher. There was no significant between control sham group and American ginseng sham group. The results demonstrated that American ginseng could improve cardiac dysfunction induced by overload pressure.3. The effects of American ginseng on heart weight, lung weight and myocyte size in miceAfter TAC operation, compared to the control TAC group, the heart weight, lung weight and myocyte size were decreased in American ginseng TAC group. There was no significant between control sham group and American ginseng sham group. The results suggested that American ginseng could inhibit hypertrophy.4. The effects of American ginseng on heart fibrosis in mice4weeks after TAC operation, the LV fibrosis area of control TAC group was13.00%, while the LV fibrosis area of American ginseng TAC group was9.89%, which was similar to the fibrosis in IVS. Although the RV fibrosis area of American ginseng TAC group was smaller than that of control TAC group, there was no significant difference between the two groups. The result suggested that Nrf2overexpression could inhibit LV and IVS fibrosis caused by pressure overload.。5. The effects of American ginseng on cardiomyocytes apoptosis in mice4weeks after TAC operation, TUNEL-positive cells were increased compared with the sham-operated mice. There was no significant difference between control sham group and American ginseng sham group. Compared to the control TAC group, the number apoptotic cells was decreased in American ginseng TAC group. These results indicated that could inhibit myocardial apoptosis induced by pressure overload.6. The effects of American ginseng on fetal gene mRNA expression in miceAfter TAC operation, there was an upregulation of ANF, BNP, and β-MHC, as well as a downregulation of α-MHC in the control TAC group. However, the expression of ANF, BNP, β-MHC and α-MHC was decreased and increased respectively in American ginseng TAC group. Therefore, American ginseng could regulate the ratio of a-MHC/(3-MHC in the heart, inhibit fetal gene expression and protect heart from Ventricular remodeling.7. The effects of American ginseng on cardiac oxidative stress in miceThe myocardial levels of4-HNE and8-OHdG were significantly increased in mice4weeks after TAC. The TAC-induced oxidative stress was decreased in the hearts of American ginseng TAC group, compared to the control TAC group. These results demonstrate that American ginseng could inhibit oxidative stress in the heart secondary to pathological pressure overload.8. The effects of American ginseng on Nrf2protein expressionThe protein expression of Nrf2was increased induced by TAC operation in control TAC group, however, there was no significant difference compared to control sham group, which was consistent with the results we observed in our other previous experiment. In American ginseng group, the was no significant difference between American ginseng sham group and control sham group, while the protein level of Nrf2was higher in American ginseng TAC group than that in control TAC group. This suggested that American ginseng could promote protein expression of Nrf2.9. The effects of American ginseng on mRNA expression of Nrf2and its downstream genes in miceAfter TAC operation, the mRNA expression of Nrf2was increased, which was further increased in American ginseng TAC group. In control group, there was no significant difference between sham group and TAC group. Compared to control TAC group, the expression of these genes, including HO-1, NQO-1and Txnrd-1were further increased in American ginseng TAC group. These results indicated that American ginseng could induce the mRNA expression of Nrf2and its downstream ant...
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