Stem cell mechanisms during left ventricular remodeling post-myocardial infarction:Repair and regeneration

Post-myocardial infarction(MI),the left ventricle(LV)undergoes a series of events collectively referred to as remodeling.As a result,damaged myocardium is replaced with fibrotic tissue consequently leading to contractile dysfunction and ultimately heart failure.LV remodeling post-MI includes inflammatory,fibrotic,and neovascularization responses that involve regulated cell recruitment and function.Stem cells(SCs)have been transplanted post-MI for treatment of LV remodeling and shown to improve LV function by reduction in scar tissue formation in humans and animal models of MI.The promising results obtained from the application of SCs post-MI have sparked a massive effort to identify the optimal SC for regeneration of cardiomyocytes and the paradigm for clinical applications.Although SC transplantations are generally associated with new tissue formation,SCs also secrete cytokines,chemokines and growth factors that robustly regulate cell behavior in a paracrine fashion during the remodeling process.In this review,the different types of SCs used for cardiomyogenesis,markers of differentiation,paracrine factor secretion,and strategies for cell recruitment and delivery are addressed.

Xinfuli Granule improves post-myocardial infarction ventricular remodelingand myocardial fibrosis in rats by regulating TGF-β/Smads signaling pathway

Background Recent clinical and experimental studies have confirmed the effects of Xinfuli Granule （XG）, a compound Chinesemedicine in the prevention and treatment of heart failure （HF）. This study aimed to investigate the effects and the mechanisms of XG onventricular reconstruction in rats with acute myocardial infarction （AMI）. Methods Sprague-Dawley rats were subjected to left anteriordescending branch ligation. The rats that survived 24 h were randomly assigned to five groups： medium-dose of XG group （MI＋XGM）,high-dose of XG group （MI＋XGH）, carvedilol group （MI＋C）, medium-dose of XG ＋ carvedilol group （MI＋C＋XGM）. Fourteen rats under-went identical surgical procedures without artery ligation, serving as sham controls. At 28 days, left ventricular weight to body weight（LVW/BW） and heart weight to body weight （HW/BW） were calculated; left ventricular ejection fraction （LVEF）, left ventricular shorteningfraction （LVFS）, left ventricular internal diameter at systole （LVIDS） were measured by ultrasound; HE staining, Masson staining, and Siriusred staining were used to assess the myocardial pathological and physiological changes as well as myocardial fibrosis area and non-infarctzone Ⅰ/Ⅲ collagen ratio. Expression of Smad3 were detected and analyzed by Western blot, immunohistochemistry and immunofluorescenceP-Smad3, Smad2 and Smad7 in the TGF-13/Smads signaling pathway were also analyzed by Western blot. Results The LVIDS （P 〈 0.01）,HW/BW （P 〈 0.05）, type UIII collagen ratio （P 〈 0.01） and myocardial collagen （P 〈 0.01） decreased significantly while the LVW/BW,LVFS （P 〈 0.05） increased significantly in MI＋XGM group as compared with those in other groups. The expression of key signal moleculesof the TGF-β/Smads signaling pathway, including Smad3, P-Smad3 and Smad2 protein were decreased, while the expression of Smad7 in-creased in both XG and carvedilol treatment groups as compared to those of the MI group （all P 〈 0.01）. Immunohistochemistry and im-munofluorescence further confirmed the down-regulated Smad3 expression. Conclusion XG can improve ventricular reconstruction andinhibit myocardial fibrosis in rats with AMI by regulating TGF-β/Smads signaling pathway.

Effects of Tribuli Saponins on Left Ventricular Remodeling after Acute Myocardial Infarction in Rats with Hyperlipidemia

Objective: To observe the effect of Tribuli saponins (TS) on left ventricular remodeling after acute myocardial infarction(AMI) in rats with hyperlipemia.Methods: A composite model of myocardial infarction and hyperlipemia was established and treated with TS to observe its effect on cardiac structure and function by echocardiography.Results: (1) Cardiac function: As compared with the model group, the fractional shortening (FS) and ejection fraction (EF) got increased, and the left ventricular end diastolic volume (LVEDV) and systolic volume (LVESV) got lower in the groups treated with high dose TS and simvastatin ( P<0.05 or P<0.01), but difference between the two treated groups was insignificant. (2) Cardiac structure: As compared with the model group, the left ventricular dimension end diastole (LVDd) and systole (LVDs) in the groups treated with high dose TS and simvastatin got lower (P<0.05 or P<0.01). No treatment showed any effect on the thickness of ventricular wall. (3)Ventricular weight index: Both high dose TS and simvastatin could decrease the left ventricular weight index (LVWI) (P<0.05).Conclusion: TS could attenuate the left ventricular remodeling after acute myocardial infarction to certain extent, and improve cardiac function in the early phase after AMI, thus playing an important role in controlling morbidity and mortality of cardiac events and long-term prognosis.

Therapeutic Mechanism of Yuxingeng Liquid(愈心梗液)on Early Ventricular Remodeling with Acute Myocardial Infarction in Rats

Objective:To examine the therapeutic mechanism of Yuxingeng liquid (愈心梗液,YXGL) on early ventricular remodeling in Wistar rats with acute myocardial infarction(AMI). Methods: Measuring the cardiac index (CI), left ventricular weight (LVW) and cardiac myocyte dimension and observing the concentration of endothelin (ET) and angiotensin E (Ang n ) in the plasma and myocardium. AMI models were established by ligature of left anterior descending coronary artery and the rats with AMI were randomly divided into 6 groups: the model group, sham-operation group, captopril group, high dosage YXGL group, middle dosage YXGL group and low dosage YXGL group. From the next day after modeling, the rats had been given YXGL through the gastric tube, which lasted for 4 weeks. And then, CI, LVW and concentration of ET and Ang II in the plasma and myocardium were tested. Results: Comparing with model control group, high dosage YXGL, middle dosage YXGL and captopril can all significantly reduce CI, LVW, cardiac cell dimension and content of ET and AngII in both plasma and myocardium (P< 0. 05 or P<0. 01). Conclusion: YXGL can remarkably reduce LVW, CI and concentration of ET and Ang II,and lowering the concentration of ET and Ang II is possibly one of the mechanisms intervening the pathological course of the early ventricular remodeling in rats with AMI.

Effect of Astragalus Injection on Left Ventricular Remodeling in Aged Patients with Acute Early-stage Myocardial Infarction

Objective: To observe the effect of Astragalus Injection (AI) on left ventricular remodeling in aged patients with acute myocardial infarction (AMI). Methods: Patients with AMI were randomly divided into the AI group (46 cases) treated with AI and the control group (46 cases) treated conventionally. Left ventricular end-diastolic volume index (LVEDVI), left ventricular end-systolic volume index (LVESVI), anterior endocardial segmental length (ASL) and posterior endocardial segmental length (PSL) were all assessed by echocardiogram after 1 week and 4 weeks treatment. The cardiac systolic and diastolic functions were detected by nuclide gating cardiac blood pool imaging at the 4th week. Results: After four weeks' treatment, no obvious change of LVEDVI, LVESVI and ASL in the AI group was found, but these indexes increased significantly in the control group, with significant difference shown between the two groups (P<0. 05). As compared with the control group, the left ventricular ejection fraction (LVEF), left ventricular peak ejecting rate (LVPER) and left ventricular peak filling rate (LVPFR) were heightened, the time for peak filling rate (LVTPFR) in the left ventricle was shortened in the AI group. Conclusion: AI is one of the effective drugs in reversing left ventricular remodeling in aged patients with AMI.

Comparative Proteomic Analysis in Left Ventricular Remodeling following Myocardial Infarction in Rats

Objective Left ventricular remodeling （LVR） following myocardial infarction （MI） is a key pathophysiological process in which MI develops into heart failure. The exact mechanism of LVR remains unclear. We performed differential proteomic analysis on the myocardia of rats with LVR after MI, to explore the mechanism of ventricular remodeling after MI. Methods In the LVR group （n=12）, after the anterior descending coronary artery was ligated, the rats were fed for four weeks before the LVR models were established. Rats in the sham-operated group （n=11） underwent thread-drawing without ligation. The hemodynamic parameters, pathological findings, and proteomics were compared between the two groups. Results In the LVR group, the left ventricular end-diastolic pressure increased, the maximal left ventricular pressure increase/decrease ratio decreased significantly, and the left ventricular systolic pressure decreased. H-E staining and Masson staining of cardiac muscle tissues of the LVR group showed myocytolysis, disarray, and collagen proliferation. Twenty-one differentially expressed proteins were detected by proteomic analysis. We validated two proteins using western blot analysis. The differentially expressed proteins could be divided into six categories： energy metabolism-related proteins, cytoskeletal proteins, protein synthesis-related proteins, channel proteins, anti-oxidation- related proteins, and immune-related proteins. Conclusion These differentially expressed proteins might play key roles in LVR following M

Influence of Transplantation of Allogenic Bone Marrow Mononuclear Cells on the Left Ventricular Remodeling of Rat after Acute Myocardial Infarction

To probe into the influence of transplantation of allogenic bone marrow mononuclear cells （BM-MNCs） on the left ventricular remodeling of rat after acute myocardial infarction （AMI）, 60 male Wistar rats were evenly divided into three groups at random： control group 1, control group 2 and transplantation group. In control group 1, chest was opened without ligation of coronary artery; in control group 2 and transplantation group, the left anterior descending branch of coronary artery was ligated to establish AMI model. Prepared culture medium and allogenic BM-MNCs suspension were respectively implanted the surrounding area of infracted cardiac muscle via epicardium of control group 2 and transplantation group. Four weeks after the operation, the osteopontin gene （OPN mRNA, P〈0.01）, type Ⅰ collagen （P〈0.01） and angiotensin Ⅱ （AngⅡ, P〈0.01） content in the left ventricular non-infracted myocardium, and the Ang Ⅱ density in blood plasma （P〈0.05） of transplantation group and control group 2 were all significantly higher than that of control group Ⅰ. In the transplantation group, the myocardial OPN InRNA, type Ⅰ collagen and Ang Ⅱ content of non-infracted zone in left ventricle, and the Ang Ⅱ concentration in blood plasma were all significantly lower than those of control group 2 （P〈0.05 for all）. It is concluded that allogenic BM-MNCs transplantation may ease left ventricular remodeling after AMI by inhibiting the synthesis of type Ⅰ collagen in the cardiac muscle and down-regulating the expression of Ang Ⅱ and OPN gene.

COMPARISON OF THE EFFECTS OF LOSARTAN,ENALAPRIL AND THEIR COMBINATION IN THE PREVENTION OF LEFT VENTRICULAR REMODELING AFTER ACUTE MYOCARDIAL INFARCTION IN THE RAT

Objectives. To compare the effects of losartan, enalapril and their combination in the prevention ofleft ventricular remodeling (LVRM) after acute myocardial infarction (AMI) in the rat. Methods. AMI model was induced in female SD rats by ligating left coronary artery. Forty-eight hours after the procedure, 83 surviving rats were randomized into one of the following 4 groups: 1 ) AMI control group (n =19), 2) losartan group (n= 22, 3 mg @ kg - 1 @ d - 1 ), 3 ) enalapril group (n = 20, 1 mg @ kg - 1 @ d - 1 ), 4) losartan - enalapril combinative group (n = 22, 3 and 1 mg @ kg- 1 @ d - 1 respectively). 5 ) sham-operated group ( n =10) and 6) normal rats group (n = 10) were selected randomly to serve as non-infarction controls. Losartan and enalapril were delivered by direct gastric gavage. After 4 weeks of medical therapy, hemodynamic studies were performed in each group, then the rat hearts were fixed with 10% formalin and pathologic analysis on them was performed. Complete experimental data was obtained in 56 rats, comprising 1 ) AMI controls (n = 11 ), 2) losartan group (n = 10), 3 ) enalapril group (n = 10), 4) the combination of losartan and enalapril group (n = 11 ),5) sham - operated group (n = 6) and 6) normal controls (n=8). Results. There were no significant differences among the 4 AMI groups in MI size (41.7% ～ 43.4%, all P＞ 0.05). Compared with sham group, the left ventricular (LV) end diastolic pressure (LVEDP), volume (LVV), long and short axis length (L and D), as well as LV absolute and relative weight (LVAW and LVRW)in AMI group were all significantly increased ( P ＜0.05 ～ 0. 001 ); whereas the maximum left ventricular pressure rising and droping rates ( + dp/dt) and their corrected values by LV systolic pressure ( + dp/dt/LVSP)were significantly reduced (all P ＜0.001 ), indicating LVRM occurred and LV systolic and diastolic function impaired after AMI. Compared with AMI group , LVEDP, LVV, LVAW and LVRW were all significantly decreased (P ＜0.05～0.001 ); while + dp/dt/LVSP were significantly enhanced in all 3 treatment groups (P ＜0.05～0.001 ) except -dp/dt/LVSP in losartan group (P＞ 0. 05 ). There were no significant differences in the above indices among the 3 treatment groups (all P＞ 0.05). Conclusion. Both losartan and enalapril can prevent from LVRM after AMI in the rat and improve LV function with equivalent effects. There seems no additive effect when the 2 drugs are used in combination.

Hypoxia training attenuates left ventricular remodeling in rabbit with myocardial infarction

ObjectivePrevious 研究证明组织缺氧 preconditioning 能保护心脏的功能免于随后的心肌的梗塞损害。然而，在在心肌的梗塞以后室的左的组织缺氧的效果仍然是不清楚的。这研究因此试图调查在在兔子柱子的左室的改变上训练的组织缺氧的效果心肌的 infarction.MethodsAdult 男性兔子随机被划分成三个组：那么组织(假冒操作) ，组 MI (心肌的梗塞仅仅) 并且组 MI-HT (加组织缺氧训练的心肌的梗塞) 。心肌的梗塞被左室的分支结扎导致。训练的组织缺氧在一个比重低於脑脊髓液的房间被执行(在 4000 m 的高度有相等的状况， F i 为 1 h/day 的 O 214.9%) ，为四个星期的 5 天 / 星期。在端点，在血浆的脉管的 endothelial 生长因素(VEGF ) 被测量。梗塞尺寸和毛状的密度被组织学检测。左室的改变和功能被 echocardiography.ResultsAfter 估计 4 星期的实验，与这个组相比那么，在组 MI 的血浆 VEGF 层次(130.27 ±；18.58 pg/mL， P <；0.01 ) 并且 MI-HT (181.93 ±；20.29 pg/mL， P <；0.01 ) 显著地被增加。在组 MI-HT 的梗塞尺寸(29.67%±；7.73%) 显著地被死亡，当时它的毛状的密度(816.0 ±；122.2/mm 2) 显著地被增加。为组 MI 和 MI-HT，而左室的喷射部分被减少，左室的结束心脏舒张、结束收缩的尺寸被增加。与组 MI 相比，然而，组 MI-HT 减少了留给室结束心脏舒张(15.86 ±；1.09 公里， P <；0.05 ) 并且结束收缩的尺寸(12.10 ±；1.20 公里， P <；0.01 ) 显著地并且改进左室的喷射部分(54.39 ±；12.74 公里， P <；0.05 ) 训练可以改进的 .ConclusionHypoxia 让室的功能和还原剂与 MI 在兔子经由 angiogenesis 改变。

Effect of exercise training on left ventricular remodeling in patients with myocardial infarction and possible mechanisms

BACKGROUND A growing amount of evidence provides support for the hypothesis that acute myocardial infarction(AMI)patients should go through cardiopulmonary exercise testing(CPET)about 3-5 d after AMI is diagnosed,make reasonable exercising prescription,and conduct exercise training under guidance.AIM To investigate the effect of exercise training(ET)on left ventricular systolic function and left ventricular remodeling(LVRM)and to study the possible mechanisms of LVRM by the changes of matrix metallopeptidase 9(MMP-9)and tissue inhibitor of metalloproteinases 1(TIMP-1)in patients with acute STsegment elevation myocardial infarction(STEMI).METHODS Sixty patients with first STEMI undergoing direct percutaneous coronary intervention from February 2008 to October 2008 were randomly assigned to an exercise group(n=30)and a control group(n=30).The levels of MMP-9 and TIMP-1 were measured in all patients at 1 d,10-14 d,30 d,and 6 mo after admission.Two-dimensional echocardiography and cardiopulmonary exercise testing were done in patients at 10-14 d and 6 mo after admission.RESULTS There was no significant difference in CPET at baseline between the exercise group and the control group.At 6 mo,the time of exercise,peak and anaerobic threshold values of O2 uptake,and metabolic equivalents increased in both groups,but markedly increased in the exercise group.At baseline,there were no significant differences in left ventricular ejection fraction(LVEF)between the two groups.At 6 mo,LVEF increased in the exercise group,but not in the control group.At 6 mo,the percentage of patients with positive result of LVRM was 26.6%in the exercise group and 52.6%in the control group(P<0.05).The levels of plasma MMP-9 and TIMP-1 and the ratio of MMP-9 to TIMP-1 in both groups had no significant difference at 1 d and 10-14 d after AMI,but at 30 d and 6 mo,the levels of plasma MMP-9 and TIMP-1 in the exercise group were significantly lower than those in the control group;the ratio of MMP-9 to TIMP-1 in the exercise group was significantly higher than that in the control group.CONCLUSION ET under supervision based on home condition in early and recovery stage of AMI can improve exercise cardiopulmonary function and prevent the LVRM.Therefore,it may reduce unfavorable remodeling response by decreasing the levels of plasma MMP-9 and TIMP-1 and adjusting the ratio of MMP-9 to TIMP-1 hereafter.

Effects of Perindopril on Left Ventricular Remodeling and Osteopontin Expression in Rats With Myocardial Infarction

Objectives To observe the effects of perindopril on left ventricular remodeling and myocardial osteopontin expression in rats with myocardial infarction. Methods In this study male adult SD rats were randomly divided into 3 groups: sham-operation group, MI-saline group and MI-perindopril group. Left anterior descending artery was ligated to generate myocardial infarction. Perindopril (2 mg/kg body weight/day) was administered from the next day of MI. Four weeks later, left ventricular diameter (LVEDD and LVESD) and left ventricular ejection fraction was estimated with echocardiography, LVSP, LVEDP and±dp/dtmax was detected with hemodynamic measurement, cardiomyocyte diameter and interstitial fibrosis infiltration were evaluated with histological methods, and myocardium osteopontin protein expression level was detected with western blot. Results ①Compared with the sham-operation group, all rats with MI developed significant systolic and diastolic dysfunction, as was indicated by decreased LVEF, LVSP and±dp/dtmax, as well as increased LVEDP. ②Rats with MI showed significantly dilated left ventricles and higher ventricular weight / body weight ratio, significantly increased cardiomyocyte diameter and marked interstitial fibrosis in the non-infarction area. ③Perindopril treatment partly prevented cardiac dysfunction and left ventricular remodeling as indicated by the parameters mentioned above. ④No osteopontin protein was detected in myocardium of sham-operation rats. In rats with MI, high level osteopontin protein expression was significantly inhibited by perindopril treatment. Conclusions In rats with MI, perindopril treatment significantly prevented left ventricular remodeling and myocardium osteopontin protein expression.

The effect of Rhodiolae treating chronic myocardial infarction with heart failure on left ventricular remodeling and serum inflammatory factors

Objective:To explore the effect of rhodiolae treating chronic myocardial infarction with heart failure on left ventricular remodeling and serum inflammatory factors.Methods:A total of 100 cases of chronic myocardial infarction with heart failure were selected and randomly divided into treatment group and control group with 50 cases in each group, the control group was treated with strong heart, dehydration, nutrition myocardium, infection prevention and western comprehensive treatment, the treatment group was given rhodiola treatment based on the western medicine treatment, compared the changes of left ventricular remodeling indexes and serum inflammatory factors of two group patients before treatment (T0), 1 months of treatment (T1), 3 months of treatment (T2).Results: (1) There was statistical significance difference at different time points LVEF, LVEDD, LVESD, LVSTD, LVPWTD. LVEF, LVSTD, LVPWTD: T2 > T1 > T0, LVEDD, LVESD: T2 < T1 < T0;In treatment group LVEF, LVSTD and LVPWTD increased, and the decline rate of LVEDD and LVESD was higher than that of control group;(2) There was statistically significant difference in different time points of IL-6, hs-CRP, and NT-proBNP, serum IL-6, hsCRP and NT-proBNP levels: T2 < T1 < T0;The serum IL-6, hs-CRP and NT-proBNP levels of treatment group decreased more than control group.Conclusion: Rhodiolae is helpful to improve the left ventricular remodeling and serum inflammatory factors in patients with chronic myocardial infarction and heart failure.

EflFect of hepatocyte growth factor on left ventricular remodeling after acute myocardial infarction in canine

Background and objectives To investigate the effect of hepatocyte growth factor (HGF) on left ventricular (LV) remodeling after acute myocardial infarction (AMI). Methods AMI was produced by ligation of proximal left anterior descending coronary artery(LAD) in 12 mongrel canines. These animals were randomized into 2 groups. In HGF group (n=6), canines were injected with pcDNA3-HGF lml (about 300ug) at the margin of infarcted myocardium; in control group (n=6) canines were injected with equal volume of normal saline. Cardiac function and left ventricular remodeling were evaluated with echocardiography at 1, 4, 8 weeks after MI. LV myocardium specimens were obtained at 8 weeks and stained with hematoxylin and eosin for histological examination or with sirius red to assess the collagen content. Results Compared with control group, LVEF in HGF group was significantly higher at 4 weeks (49.61+6.66 vs 39.84+6.39; P＜0.05) and at 8 weeks (51.57+8.53 vs 40.61+7.67; P＜0.05) after AMI, while LVESV was significantly lower in HGF group than that in control group at 8 weeks after AMI (18.98+3.47 vs 25.66+5.86; P＜0.05). Posterior left ventricular wall thickness decreased significantly from 1 wk to 8 wks after AMI in control group, while remained unchanged in HGF group. Compared with control group, histological examination showed more neovascularization and less scar, and sirius red staining indicated higher volume of type Ⅲ collagen (7.10±4.06% vs 3.77±1.09%; P＜0.05) and lower collagen Ⅰ/Ⅲ ratio value (1.11±0.52 vs 2.94±2.48; P＜0.05)in HGF group. Conclusion HGF gene transfer might improve cardiac function and LV remodeling after acute myocardial infarction by stimulating angiogenesis, reducing fibrosis, and reducing myocardial scarring.

Effect of angiotensin receptor neprilysin inhibitor on ventricular remodeling after myocardial infarction in rats

Objective:To investigate the effect of Angiotensin Receptor Neprilysin Inhibitor(ARNI)on ventricular remodeling after AMI in rats.Methods:Sixty male SD rats were randomly divided into Control group,AMI group,AMI-valsartan group,AMI-ARNI group,15 rats in each group,ligating the left coronary anterior descending artery to establish the rat model of AMI.Valsartan group and ARNI group were treated with valsartan(34mg/kg/day)and ARNi(68mg/kg/day)for 6 weeks,the Control group and AMI group were given the same amount of normal saline.LVIDd,LVIDs,EF were measured by color doppler echocardiography before and 6 weeks after treatment.After 6 weeks,the rats were sacrificed,the hearts were weighed,then myocardial tissue Masson staining was performed to calculate the collagen volume fraction(CVF).Results:compared with the control group,LVIDs increased significantly with the reduction of EF in the AMI group,valsartan group and ARNI group(P<0.05).After 6 weeks of treatment,compared with the AMI group,LVIDd and LVIDs both reduced significantly with the increase of EF in the ARNI group(P<0.05).Compared with the control group,the left ventricular weight,right ventricular weight and atrial weight all increased significantly in the AMI group,valsartan group,and ARNI group(P<0.05);compared with the AMI group,the left ventricular weight,right ventricular weight,atrial weight and CVF reduced significantly in the valsartan group and ARNI group(P<0.05);compared with the valsartan group,the left ventricular weight and CVF further reduced in the ARNI group.(P<0.05).Conclusions:ARNI has the effect of reversing ventricular remodeling after AMI in rats,which can reduce left ventricular volume,increase myocardial contractility,and inhibit myocardial cell hypertrophy and fibrosis.

Yiqi Huoxue traditional Chinese decoction affect ventricular remodeling in rats with heart failure after myocardial infarction by regulating osteopontin expression

Objective:To investigate the mechanism of Yiqi Huoxue traditional Chinese medicine affecting the osteopontin(OPN)level in myocardial tissue and improving ventricular remodeling in heart failure rats after myocardial infarction.Methods:Forty SPF-grade SD male rats were prepared,and 10 rats were reserved as blank controls.The remaining rats were prepared by anterior descending coronary artery ligation combined with reduced diet and exhausted swimming to prepare a rat model of heart failure after myocardial infarction.The rats in the blank group and the model group were orally administered with distilled water,the Chinese medicine group was administered with Yiqi Huoxue Chinese medicine decoction,and the western medicine group was administered with captopril.After 6 weeks of treatment,small animal ultrasound was used to detect changes in ventricular structure and function in rats.Kill all the rats,and take myocardial tissue,observe the morphological changes of myocardial tissu under a light microscope.Use real-time quantitative PCR to detect the expression of OPN mRNA in rat myocardial tissue,and use immunohistochemical method to detect the expression of OPN protein in myocardial tissue.Results:Compared with the blank group,the left ventricular ejection fraction(EF),left ventricular short axis shortening fraction(FS)of the model group were significantly reduced,and the left ventricular end-diastolic diameter(LVEDD)and left ventricular end-systolic diameter(LVESD)were significantly increased,OPN mRNA and protein expression were significantly up-regulated(P<0.01),and myocardial structure disorder was seen under light microscope.Compared with the model group,the EF and FS of the Chinese medicine group and the Western medicine group were both significantly increased,the LVEDD and LVESD were significantly reduced,the expressions of OPN mRNA and protein were significantly reduced(P<0.01),and the myocardial structure was significantly improved under light microscopy.There was no statistically significant difference between the western medicine group and the traditional Chinese medicine group(P>0.05).Conclusion:Yiqi Huoxue Chinese medicine may reduce the expression of OPN in myocardial tissue,improve ventricular remodeling,improve cardiac function and prevent heart failure after myocardial infarction.

Effects of astragalus polysaccharides on ventricular remodeling and miRNA-21 in rats with acute myocardial infarction

Objective:To investigate the effect of Astragalus polysaccharides(APS)on myocardial remodeling and expression of miR-21 after myocardial infarction.Methods:Sixty SPF grade healthy male rats were divided into the sham operation group,the model group,astragalus polysaccharide low,medium and high dose groups and atorvastatin group randomly with 10 rats in each group.The left anterior descending coronary artery(LAD)was ligated to establish myocardial infarction model in rats,and the corresponding drug intervention was given for 4 weeks.The changes of myocardial morphology and collagen were observed by HE and Masson staining.The levels of IL-1β,IL-6,TNF-αand IL-10 were detected by ELISA.The mRNA expressions of miR-21,MMP2,TIMP-2,Col-I,and Col-III was detected by RT-PCR.The protein expressions of TLR4,MyD88 and NF-κB p65 were detected by Western blot.Results:Compared with the model group,APS could improve the pathological morphology of myocardial tissue,increase the level of IL-10 in myocardial tissue,reduce the staining area of collagen and the contents of IL-1β,IL-6 and TNF-α(P<0.05).At the same time,APS could decreased the expression of MMP2,Col-I and Col-ⅢmRNA and the ratio of MMP2/TIMP-2,and increased the expression of TIMP-2 mRNA and miR-21 significantly(P<0.05).Furthermore,APS could significantly reduce the expression of TLR4,p-NF-κB p65 and MyD88 protein in myocardial tissue of rats with myocardial infarction,and the differences were statistically significant when compared with the model group(P<0.05).Conclusion:APS can inhibit the activation of TLR4/MyD88/NF-κB signaling pathway by upregulating the expression of miR-21,which plays a therapeutic role in ventricular remodeling after acute myocardial infarction.

Effect of carvedilol on cardiac function and left ventricular remodeling in rats after acute myocardial infarction

Objective: To observe the effect of carvedilol injection on left ventricular function and collagen remodeling in rat with myocardial infarction. Methods: Sixty rats with a model of myocardial infarction were randomly divided into nine groups. The rats of therapeutical group were treated with carvedilol injection (2 mg/d intraperitoneal injection) and/or captopil (2 g/L drinking water). Acute myocardial infarction (AMI) group did not receive drug treatment. The animals were sacrificed at 4 weeks and 8 weeks after coronary artery ligation. The levels of plasma angiotensin Ⅱ and plasma aldosterone and left ventricle function were determined at different time. The collagen content and the ratio of type I and Ⅲ collagen of noninfarcted area were also assessed. Results: Compared with AMI group, the levels of plasma and myocardium angiotensin Ⅱ and plasma aldosterone in both carvedilol and captopil group decreased at the eighth week (P<0.05). In addition, carvedilol improved systolic and diastolic function (P<0.05). Compared with sham group, both collagen content and the ratio of type Ⅰ/Ⅲ collagen of noninfarcted area increased in AMI4 and AMI8 group (P<0.05). The hydroxyproline levels and the ratio of type Ⅰ/Ⅲ collagen significantly decreased after carvedilol and/or captopil treatment , compared with AMI group at 4 or 8 week (P<0.05). Conclusion: Carvedilol can improve cardiac function after myocardial infarction and has beneficial effect on left ventricular remodeling.

Total flavonoids of bugloss limits left ventricular remodeling after myocardial infarction in mice

OBJECTIVE To investigate the effects of total flavonoids of bugloss(TFB) on left ventricular(LV) remodeling after myocardial infarction(MI),LV size and function was compared in mice subjected to left anterior descending coronary artery ligation.METHODS 28 d after MI,the infarcted fraction of the LV and LV mass,systolic and diastolic function were measured.Capillary density and myocyte width in the nonischemic portion of the LV were also determined.RESULTS 28 d after MI,both groups had dilated LVs with decreased fractional shortening and lower ejection fractions.Although the infarcted size of the LV was similar in both groups,LV end-diastolic internal diameter,end-diastolic volume,and mass were lower,but fractional shortening,ejection fraction,and the maximum rate of developed LV pressure(dp/dtmax) were greater in TFB treated mice than in control mice.Impairment of diastolic func.tion,as measured by the time constant of isovolumic relaxation(t) and the maximum rate of LV pres.sure decay(dp/dtmin),was more marked in control mice than in TFB treated mice.Mortality after MI was greater in control mice than in TFB treated mice.In control mice,capillary density and myocyte width in the nonischemic portion of the LV did not differ before and 28 days after MI,whereas in TFB treated mice,capillary density increased and myocyte width declined after MI.CONCLUSION These results suggest that the presence of TFB limits LV dysfunction and remodeling in a murine model of MI in part by decreasing myocyte hypertrophy in the remote myocardium.

Preparation of Acute Myocardial Infarction Model for SD Rats and Ventricular Remodeling

[Objectives] To prepare an acute myocardial infarction model for SD rats and conduct ventricular remodeling. [Methods] 45 male Sprague-Dawley( SD) rats were randomly selected in 60 male rats as the model group and the rest rats were sham operation group. For the model group,the left anterior descending coronary artery was ligated,while the sham operation group was not ligated. 4 weeks after the operation,hemodynamics was used to measure the cardiac function of both groups. HE staining and Masson staining were used to observe the changes in myocardial histopathology and myocardial fibrosis of both groups. [Results] Compared with the sham operation group,the model group rats showed significant decrease in the left ventricular systolic pressure( LVSP) and left ventricular pressure maximum rising and dropping rate( ± d_p/d_(tmax)) and significant increase in the left ventricular end-diastolic pressure( LVEDP). HE staining showed that a large number of myocardial cell necrosis occured in the model group,while the morphology of myocardial cells of rats in the sham operation group was normal. Masson staining showed that myocardial collagen fibers in the model group were significantly increased compared with those in the sham operation group. Collagen fibers were scattered in the sham operation group. [Conclusions] It can be concluded that cardiac function of rats changed and ventricular remodeling occurred in 4 weeks after myocardial infarction.

Cardiac remodeling and physical training post myocardial infarction

After myocardial infarction(MI), the heart undergoes extensive myocardial remodeling through the accumulation of fibrous tissue in both the infarcted and noninfarcted myocardium, which distorts tissue structure, increases tissue stiffness, and accounts for ventricular dysfunction. There is growing clinical consensus that exercise training may beneficially alter the course of post-MI myocardial remodeling and improve cardiac function. This review summarizes the present state of knowledge regarding the effect of post-MI exercise training on infarcted hearts. Due to the degree of difficulty to study a viable human heart at both protein and molecular levels, most of the detailed studies have been performed by using animal models. Although there are some negative reports indicating that post-MI exercise may further cause deterioration of the wounded hearts, a growing body of research from both human and animal experiments demonstrates that post-MI exercise may beneficially alter the course of wound healing and improve cardiac function. Furthermore, the improved function is likely due to exercise training-induced mitigation of reninangiotensin-aldosterone system, improved balance between matrix metalloproteinase-1 and tissue inhibitor of matrix metalloproteinase-1, favorable myosin heavy chain isoform switch, diminished oxidative stress, enhanced antioxidant capacity, improved mitochondrial calcium handling, and boosted myocardial angiogenesis. Additionally, meta-analyses revealed that exercise-based cardiac rehabilitation has proven to be effective, and remains one of the least expensive therapies for both the prevention and treatment of cardiovascular disease, and prevents re-infarction.